description
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
5 (SEE SECTION 10; RULE 13)
“TWO COMPONENT ION EXCHANGE RESINS”
Sr. No Name Nationality Address
1. ION EXCHANGE
(INDIA) LIMITED
INDIA ION HOUSE, DR. E. MOSES
ROAD, MAHALAXMI, MUMBAI
400 011, MAHARASHTRA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
10 AND THE MANNER IN WHICH IT IS TO BE PERFORMED
2
1. FIELD OF THE INVENTION
5
The present invention relates to ion exchange resins. More particularly it relates to two
component cross-linked copolymers in bead form and strong acid cation, strong base
anion, and weak acid cation exchange resins derived there from which find uses in water
and non-water applications like drug purification, sugar processing and catalysis etc.
10
2. BACKGROUND OF THE INVENTION
15 Ion exchange resins are solid matrices which carry exchangeable ions. The resins based
on their composition may be classified as strong acid cation, weak acid cation, strong
base anion, weak base anion and amphoteric resins. These resins find applications in
diverse industrial fields such as water treatment and purification, in pharmaceutical
industry, in the separation and purification of amino acids, antibiotics, vitamins and
20 hormones, in sugar processing, in the recovery of organic acids such as citric, ascorbic
and tartaric acids. They are also used as catalysts in a wide range of chemical reactions,
notably esterification and trans-esterification.
3
The ion exchange resins are generally prepared in two steps. In the first step the crosslinked polymer bead is prepared by the suspension polymerization technique. The
suspension polymerization techniques have been adequately described in “Polymer
Processes”, edited by Calvin E. Schildknecht, published in 1956 by Interscience
5 Publishers, Inc., New York, Chapter III, "Polymerization in Suspension” by E.
Trommsdoff and C. E. Schildknecht, wherein are listed various monomers which can be
used in the preparation of polymer beads. Suspension polymerization for the synthesis
of ion exchange resins has been in particularly described in US patent 4,224,415. It is
well known that the thermal and mechanical properties of the ion exchange resins are
10 primarily governed by the composition and properties of the cross-linked polymer beads
prepared in the first step. These beads are subsequently functionalized to yield either 1)
strong acid cation, 2) weak acid cation, 3) strong base anion, 4) weak base anion or 5)
amphoteric resins. The functionalization techniques used to obtain the ion exchange
resins from the cross-linked polymer beads are well-known in the art and have been
15 described in various US patents. Methods of synthesis of strong acid cation exchange
(SAC) resins are described in US patents 2,500,149; 2,631,127; 2,664,801; 2,764,564
and 3,266,007 which describe sulfonating reagents and reaction conditions. Methods of
synthesis of strong base anion exchange (SBA) resins are described in US patents
2,597,492; 2,597,493; 2,616,817; 2,642,417; 2,960,480 and 3,311,602 which describe
20 halo alkylating agents and conditions. US patents 2,616,877; 2,642,417; 2,632,000;
2,632,001and 2,992,544 describe aminating agents and aminating conditions. All of
these are incorporated herein fully by way of reference.
4
The performance of the ion exchange resins during a given application depends upon the
composition, morphology and properties of the cross-linked polymer beads prepared in
the first step and the type and extent of functionalization carried out during the second
step, which determines its total exchange capacity (TEC).
5
Ion exchange is a diffusion-controlled process, more particularly under typical operating
conditions it is controlled by pore diffusion rather than by film diffusion (See "Ion
Exchange,” F. Helfferich, McGraw-Hill Book Co. Inc., 1962). As a result, the ion
10 exchange sites buried within the resin bead are not readily accessible and the time for
these sites to affect ion exchange is uneconomically long for many applications. During
regeneration this often leads to long regeneration times, large regenerant volume
requirements, and ionic leakage. For the same reason such resins have to be regenerated
when only a fraction of their TEC has been utilised. Thus, useful operating exchange
15 capacity (OEC) of these resins to remove ions from a medium is lower than their TEC.
Regeneration of the ion exchange resins also leads to significant volume changes dueto
ionic concentration variation, which generates swelling induced stresses, resulting in
attrition of ion exchange beads causing reduction in the efficiency of the ion exchange
column and concomitantly the servicing costs incurred in replacing the damaged resin
20 beads.
Early attempts made to bring about uniform sulfonation and overcome swelling induced
breakage of ion exchange resins involved sulfonation of resin beads in the presence of
25 swelling solvents such as nitrobenzene. In efforts to eliminate the use of solvents during
sulfonation, US patent 4,500,652 claimed suspension polymerization of styrene and
5
divinylbenzene (DVB) in presence of monomers such as acrylic acid, methacrylic acid
and their lower alkyl esters.
5 An early solution to overcome the diffusional limitations in these gel type or
microporous resins was the use of macroporous or macroreticular resins. However, these
resins suffered from lower exchange capacities and poor mechanical properties.
10 One of the earliest solutions to this problem was to develop core shell graft copolymers
as described in US patents 3,489,699 and 3,565,833 wherein a copolymer grafted on an
inert core, formed a shell which was suitably functionalized to impart ion exchange
characteristics.
15
US patent 4,419,245 described a process for the synthesis of cross-linked ion exchange
copolymer particles wherein the seed particles were swollen by feeding monomer and
cross-linker mixture in the form of an aqueous emulsion and further polymerized.
Amongst advantages of using an emulsion were cited 1) control of distribution of feed,
20 1. improved physical contact between feed and seed, and 3) improved
kinetics of swelling of beads. The feed to seed ratio was typically 4, although a
broader range of 2 to 20, was cited. The seed contained generally 0.1% to 3%,
preferably 0.1% to 1.5%, and even more preferably 0.1% to 1% by weight of
divinylbenzene (DVB). The seeds were to be prepared in the absence of protective
25 colloids as they prevented seed from imbibing the monomer feed during
polymerization. The monomer and cross-linker mixture was fed to the seed as an
aqueous medium along with an emulsifier. The addition of protective colloid was
also to be avoided immediately after the feeding of the
6
monomer and cross-linker mixture as to avoid the creation of new population of droplets
which would lead to fines. The cross-linked copolymer beads formed were characterized
by a two-stage swelling separated by a plateau. The copolymer beads and ion exchange
resins obtained there from offered 1) good mechanical strength, 2) resistance to osmotic
5 stresses 3) resistance to external forces and 4) high fluid flow capability, which was
attributed to the core shell morphology of the cross-linked copolymer bead.
In an effort to develop ion exchange resins which exhibit improved osmotic shock
10 resistance and mechanical properties, US patent 4,564,644 and 5,068,255 described a
process comprising (a) forming a suspension of cross-linked free radical containing
polymeric matrices in a continuous phase, and (b) contacting the same with a monomer
feed comprising a monomer or monomer / cross-linker mixture which imbibed
polymeric matrices of stage (a), such that the polymerization of the fed mixture was
15 initiated by the radicals on the polymer matrix. To ensure that the polymerization of the
monomers in the monomer feed was initiated by the free radicals located on the
polymeric matrix, no initiators were added either to the monomer feed or the continuous
phase in the second stage. The copolymer beads formed exhibited core/shell morphology
such that the degree of cross-linking in the shell was lower than that in the core. The
20 copolymer beads were subsequently converted to ion exchange resins, which also
exhibited core shell morphology. The ion exchange resins exhibited resistance to
osmotic shocks as well as good mechanical strength. Applications of these resins in the
purification of power plant condensate was described in US patent 4,975,201.
Copolymer beads bearing core/shell morphology were used for the removal of the
25 alkaline earth metal and transition metal ions by incorporating (aminomethyl)
7
(hydroxymethyl) phosphinic acid groups. In an attempt to enhance the kinetics of
exchange, US patent 5,141,965 described cross-linked copolymer beads wherein weakbase exchange functionalities were substituted at haloalkylated sites most readily
accessible to diffusion. Strong base anion exchange functionalities were substituted at
5 sites least accessible to diffusion. The hydrophilicity imparted by the later, improved
overall exchange kinetics. Applications of partially sulfonated ion exchange resins in
sugar chromatography were described in EP 0,361,685.
10 The need to develop cross-linked copolymer beads containing core shell morphology
bearing even higher crosslink densities in the core as well as in the shell than those
described in US patents 5,278,193 was recognized and synthesis of such beads and ion
exchange resins derived there from was described in US patent 8,686,055.
15
1. SUMMARY OF THE INVENTION
Surprisingly it has been found that the ion exchange resins derived from the two
20 component cross-linked copolymers in bead form, wherein the cross-linked copolymer
of the first component has lower cross-linker content than the cross-linker content in the
cross-linked copolymer of the second component, exhibit an OEC/TEC ratio in the range
of 49% to 61%.
25
According to an embodiment of the present invention the weight ratio of the cross-linked
copolymer of the first component to that of the cross-linked copolymer of the second
8
component in the two component cross-linked copolymer in the bead form is in the range
of 1: 1.2 to 1:2.7.
5 According to an embodiment of the present invention the two component cross-linked
copolymers in the bead form do not exhibit core shell morphology prior to
functionalization. According to an embodiment of the present invention the two
component cross-linked copolymers in the bead form exhibit one stage swelling in
toluene wherein 100% swelling is achieved in 0.75 hrs to 24.0 hrs.
10
According to an embodiment of the present invention the monovinyl monomer for the
synthesis of the cross-linked copolymer of the first component is selected from styrene,
methyl methacrylate (MMA), methyl acrylate and methacrylic acid.
15
According to an embodiment of the present invention the monovinyl monomer for the
synthesis of the cross-linked copolymer of the second component is selected from
styrene, MMA, methyl acrylate, methacrylic acid and hydroxyl ethyl methacrylate
20 (HEMA).
According to an embodiment of the present invention the cross-linker content of the
cross-linked copolymer of the first component varies in the range of 1.8 to 3% w/w.
25 According to an embodiment of the present invention the cross-linker content of the
cross-linked copolymer of the second component varies in the range of 2 to 9% w/w.
9
According to an embodiment of the present invention the cross-linker for the crosslinked copolymer of the first component is selected from DVB, ethylene glycol
dimethacrylate (EGDMA), 1, 7-octadiene and trivinyl cyclohexane (TVCH).
5
According to an embodiment of the present invention the cross-linker for the crosslinked copolymer of the second component is selected from DVB, EGDMA, 1, 7-
octadiene and TVCH. According to an embodiment of the present invention the crosslinked copolymer of the first component is prepared by suspension copolymerization in
10 the presence of a protective colloid.
According to an embodiment of the present invention the cross-linked copolymer ofthe
second component is prepared by suspension copolymerization in the presence of a
15 protective colloid.
According to an embodiment of the present invention the monomer composition of the
cross-linked copolymer of the second component is imbibed in the cross-linked
20 copolymer composition of the first component prior to the copolymerization of the
monomer composition of the cross-linked copolymer of the second component.
According to an embodiment of the present invention the copolymerization of the
25 monomer composition of the cross-linked copolymer of the first component is completed
before the monomer composition of the cross-linked copolymer of the second
component isimbibed in the cross-linked copolymer composition of the first component.
10
According to an embodiment of the present invention the monomer composition of the
cross-linked copolymer of the first component as well as the monomer composition of
the cross-linked copolymer of the second component always contains a free radical
initiator.
5
According to an embodiment of the present invention the free radical initiator for the
monomer composition of the first component is selected from benzoyl peroxide (BPO),
dicumyl peroxide (DCP) and azobisisobutyronitrile (AIBN).
10
According to an embodiment of the present invention the free radical initiator for the
monomer composition of the cross-linked copolymer of the second component is
selected from BPO, DCP and AIBN.
15
According to an embodiment of the present invention the free radical initiator for the
monomer composition of the cross-linked copolymer of the first component and the free
radical initiator of the monomer composition of the cross-linked copolymer of the second
20 component is the same.
According to an embodiment of the present invention the free radical initiator for the
monomer composition of the cross-linked copolymer of the first component and the free
25 radical initiator of the monomer composition of the cross-linked copolymer of the second
component are different.
11
According to an embodiment of the present invention the free radical initiator for the
monomer composition of the cross-linked copolymer of the second component contains
more than one initiator.
5
According to an embodiment of the present invention, the ion exchange resin derived
from the two component cross-linked copolymer beads exhibits core shell morphology.
According to an embodiment of the present invention, the ion exchange resin derived
from the two component cross-linked copolymer beads does not exhibit core shell
10 morphology.
According to an embodiment of the present invention the ion exchange resin derived
from the two component cross-linked copolymers, is a strong acid cation exchange resin.
15 According to an embodiment of the present invention the strong acid cation exchange
resin is synthesized using a weight ratio of two component cross-linked styrene - DVB
copolymers in the bead form to sulfuric acid in the range of 1:3.6 to 1:7.2 w/w.
20 According to an embodiment of the present invention the sulfonation reaction is carried
out using sulfuric acid concentration in the range of 93 to 100% w/w.
According to an embodiment of the present invention the strong acid cation exchange
25 resin derived from the two component cross-linked copolymers in the bead form exhibits
an OEC/TEC ratio in the range of 49% to 61%.
12
According to an embodiment of the present invention the strong acid cation exchange
resin has TEC in the wet form in the range of 1.25 to 1.85 equivalents per litre (eq/L).
According to an embodiment of the present invention the strong acid cation exchange
resin has a crushing strength in the range of 500 to 1000 grams per bead (g/bead).
5
According to an embodiment of the present invention the strong acid cation exchange
resin of the present invention when subjected to osmotic shock resistance test retains a
whole bead count greater than 80%.
10
According to an embodiment of the present invention the strong acid cation exchange
resin of the present invention exhibits one or more of the following advantages during
regeneration a) better quality of treated water (i.e. low levels of ionic impurities as
15 compared to the water treated with conventional strong acid cation resins under identical
operating conditions) at lower regeneration level, b) higher regeneration efficiencies
than those for conventional resins and c) lower water requirement for washing of resin
after regeneration (water saving or less effluent).
20
According to an embodiment of the present invention the strong acid cation exchange
resin of the present invention exhibits advantages in one or more of the following
applications such as water treatment, condensate polishing unit, operations in non-water
applications like drug purification, sugar processing and catalysis etc.
25
According to an embodiment of the present invention the ion exchange resin derived
from the two component cross-linked copolymers, is a strong base anion exchange resin.
13
According to an embodiment of the present invention the strong base anion exchange
resin derived from the two component cross-linked copolymers in the bead form exhibits
an OEC/TEC ratio in the range of 55% to 57%.
5
According to an embodiment of the present invention the strong base anion exchange
resin is obtained by chloromethylation of the two component cross-linked copolymer
beads followed by amination.
10
According to an embodiment of the present invention the chloromethylation of the two
component cross-linked copolymer beads is carried out using reagents selected from
chloro methyl methyl ether (CMME), dimethoxy methane, methanol-formaldehyde
solution (MF solution) and chlorosulfonic acid (CSA).
15
According to an embodiment of the present invention the amination of chloromethylated
two component cross-linked copolymers in the bead form is carried out using aliphatic
amines selected from dimethyl ethanolamine, trimethylamine and triethylamine.
20
According to an embodiment of the present invention the strong base anion exchange
resin is synthesized using a weight ratio of two component cross-linked styrene - DVB
copolymers in the bead form to chloromethylating agent in the range of 0.93 to 2.25
25 w/w.
According to an embodiment of the present invention the strong base anion exchange
resin has TEC in the wet form in the range of 0.74 to 1.02 eq/L.
14
According to an embodiment of the present invention, the strong base anion exchange
resin exhibits core shell morphology.
5 According to an embodiment of the present invention, the strong base anion exchange
resin does not exhibit core shell morphology.
According to an embodiment of the present invention the strong base anion exchange
resin has a crushing strength in the range of 300 to 600 g/bead.
10
According to an embodiment of the present invention, the strong base anion exchange
resin when subjected to osmotic shock resistance test retains a whole bead count greater
than 80%.
15
According to an embodiment of the present invention strong base anion exchange resin
of the present invention exhibits one or more of the following advantages during
regeneration, a) better quality of treated water at lower regeneration level b) higher
regeneration efficiencies than those for conventional resins and c) lower water
20 requirement for washing of resin after regeneration (water saving or less effluent).
According to an embodiment of the present invention the strong base anion exchange
resin exhibits advantages in one or more of the following applications such as water
25 treatment, preparation of ultrapure water, condensate polishing, catalysis and sugar
processing etc.
15
According to an embodiment of the present invention the ion exchange resin derived
from the two component cross-linked copolymers, is a weak acid cation exchange
(WAC) resin.
5
According to an embodiment of the present invention the weak acid cation exchange
resin exhibits an OEC/TEC ratio in the range of 49% to 60%.
According to an embodiment of the present invention the weak acid cation exchange
resin has a TEC in the range of 1.95 to2.76 eq/L.
10
According to an embodiment of the present invention the weak acid cation exchange
resin does exhibit core shell morphology.
15
According to an embodiment of the present invention the weak acid cation exchange
resin does not exhibit core shell morphology.
20 According to an embodiment of the present invention the weak acid cation exchange
resin of the present invention exhibits advantages in one or more of the following
applications, like drug purification, water treatment and other process applications.
25 According to an embodiment of the present invention a wide range of ion exchange
resins varying in TEC, OEC/TEC ratio, moisture content and whole bead count can be
prepared by varying the composition of the cross-linked copolymer of the first
component formed in the first step, the composition of the cross-linked copolymer of the
second component formed in the second step, the weight ratio of cross-linked copolymer
16
of the first component formed in the first step to the cross-linked copolymer of the
second component formed in the second step and functionalization conditions.
5 2. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: Swelling behaviour of two component crosslinked polymer beads in toluene;
10 1. Example 1; 2) Example 14; 3) Example 16; 4) Example 15
Figure 2: Experimental set up for performance evaluation of ion exchange resins
15
Figure 3: X ray microtomography images of 1) cross-linked copolymer bead of Example
1; 2) strong acid cation exchange resin bead of Example 27; 3) strong acid cation
20 exchange resin bead of Example 40; 4) strong base anion exchange resin bead of
Example 52; 5) weak acid cation exchange resin bead of Example 53.
1. DETAILED DESCRIPTION OF THE INVENTION
25
The synthesis of ion exchange resins involves the synthesis of cross-linked polymer
beads by suspension polymerization technique, which is then appropriately
functionalized to obtain strong acid cation exchange resins, strong base anion exchange
30 resins, and weak acid cation exchange resins. The present invention involves synthesis
of two component cross-linked copolymers in the bead form wherein the cross-linked
copolymer of the first component formed in the first step has lower cross-linker content
17
than the cross-linker content in the cross-linked copolymer of the second component
incorporated in the second step, by suspension polymerization technique using
protective colloids in each step.
5
The monomer compositions used in the synthesis of cross-linked copolymers of the first
component in the bead form formed in the first step prepared by suspension
polymerization using protective colloids have cross-linker content in the range of 1.8%
to 3% w/w. These beads exhibit a limited swelling capacity in the range of 1:1.2 to 1:2.64
10 when swollen by the monomer composition constituting cross-linked copolymer of the
second component, which have cross-linker content in the range of 2% to 9% w/w.
Further the monomer composition constituting cross-linked copolymer of the second
component is absorbed in to the beads of the cross-linked copolymer of the first
component before the polymerization of monomer composition constituting cross-linked
15 copolymer of the second component is initiated. The polymerization of monomer
composition constituting cross-linked copolymer of the second component is initiated
by the initiator incorporated in the monomer composition. The two component crosslinked copolymers in the bead form so synthesized do not exhibit core shell morphology.
The beads so formed show single stage swelling behaviour in toluene, and complete
20 swelling is achieved in about twenty-four hours. These beads are further functionalized
to yield strong acid cation exchange resins, strong base anion exchange resins and weak
acid cation exchange resins. Depending upon the functionalization conditions employed,
the ion exchange resins formed may or may not exhibit core shell morphology. Ion
exchange resins so synthesized exhibit OEC to TEC ratio in the range of 49 to 61% and
25 also retain more than 80% of whole bead count when subject to osmotic shock resistance
18
test to simulate performance in repeated usage. A wide range of ion exchange resins
varying in TEC, OEC/TEC ratio, bearing good mechanical strength as reflected in the
Chatillon test and osmotic shock resistance can be prepared by the choice of the
composition of the two component cross-linked copolymers in the bead form and
5 functionalization conditions. These two component resins offer advantages in water
treatment viz. water softening and demineralization, condensate polishing, and in nonwater applications like drug purification, sugar processing and catalysis etc.
10 The invention is now illustrated by the examples below, which are representative only
and by no means limit the scope of the invention.
EXAMPLES
15
Synthesis of two component cross-linked copolymers in the bead form
20
Example 1
25
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe, a
water bath, a temperature controller and a condenser, 200 g of water was added, followed
by 0.3 g of hydroxy propyl methyl cellulose (HPMC) [Grade- viscosity of 2% aqueous
solution at 25°C is about 400 – 450 centipoises (cPs)] and 1 g of disodium phosphate
30 (DSP). The agitator speed was set at 200-300 revolutions per minute (rpm) after which
the contents were heated to 75°C over a period of 20 to 30 minutes then agitator speed
was adjusted to 60 to 70 rpm. After 15 minutes, the first monomer feed containing 94.73
19
g of styrene and 5.27g of commercially available technical grade DVB solution
containing 3 g of DVB and 0.4 g of BPO was added. The temperature was maintained
at 75°C. A sticky copolymer mass was formed after 45 minutes. At this stage the agitator
speed was increased in the range of 100 to 120 rpm, to avoid agglomeration of reaction
5 mass, and polymerization was continued for 3 hours. Then polymerization temperature
was raised to 85°C continued for 3hours and then at 95°C for 3 hours. The content of the
reaction kettle was cooled to room temperature and then aqueous portion (⁓180mL) was
siphoned out. The second monomer feed containing 147.63 g of styrene and 17.37 g of
commercially available technical grade DVB solution containing 9.9 g of DVB and 0.66
10 g of BPO was added to the cross-linked copolymer beads of the first component. Then,
monomer composition of the cross-linked copolymer of the second component was
allowed to imbibe in the cross-linked copolymer beads of first component over a period
of 2 hours. Then fresh aqueous phase consists of 540 mL of water, 0.81 g of HPMC and
2.7 g of DSP was charged to the kettle. The polymerization reaction was continued under
15 stirring (100 to 120 rpm) at 75°C for 3 hours and then at 85°C for 3 hours and further at
95°C for 3 hours. The content of the reaction kettle was then cooled to room temperature
and beads of two component cross-linked copolymer were filtered and washed until
water washings showed no foaming. The product was dried in an oven at 100°C for 8
hours. The yield of the two component cross-linked copolymer beads based on total
20 monomer charge was greater than 95%.
20
Example 2
5 The experiment was conducted as described in Example 1, except that the monomer
composition of the cross-linked copolymer of the second component did not contain
BPO. It was found that, the two component cross-linked copolymers beads obtained
were sticky, had styrene smell and the yield was 65%, which indicates second
component monomer conversion to polymer was incomplete.
10
Example 3
15
The experiment was conducted as described in Example 1, except that the monomer
composition of the cross-linked copolymer of the second component contained 0.165g
of BPO. The yield of the two component cross-linked copolymer beads was greater than
95%.
20
Example 4
25
The experiment was conducted as described in Example 1, except that the monomer
composition of the cross-linked copolymer of the second component contained 0.33 g
of BPO. The yield of the two component cross-linked copolymer beads was greater than
95%.
21
Example 5
5 The experiment was conducted as described in Example 1, except that the monomer
composition of the cross-linked copolymer of the second component contained 1.00 g
of BPO. The yield of the two component cross-linked copolymer beads was greater than
95%.
10
Example 6
15 The experiment was conducted as described in Example 1, except that the monomer
composition of the cross-linked copolymer of the second component contained 1.32 g
of BPO. The yield of the two component cross-linked copolymer beads was greater than
95%.
20
Example 7
25 The experiment was conducted as described in Example 1, except that monomer
composition of the cross-linked copolymer of the second component contained 1.65 g
of BPO. The yield of the two component cross-linked copolymer beads was greater than
95%.
22
Example 8
5 To a one litre, four-neck reaction kettle equipped with an agitator, a thermocouple probe,
a water bath, a temperature controller and a condenser, 200 g of water was added,
followed by 0.3 g of hydroxy propyl ethyl cellulose (HPEC) (Grade- viscosity of 1% aq.
solution at 25°C is about 300cPs) and 1 g of DSP. The agitator speed was set between
200 and 300 rpm after which the contents were heated to 75°C over a period of 20 to 30
10 minutes then agitator speed was adjusted to 60 to 70 rpm. After 15 minutes, the first
monomer feed containing 94.73 g of styrene and 5.27g of commercially available
technical grade DVB solution containing 3 g of DVB and 0.4 g of BPO was added. The
temperature was maintained at 75°C, a sticky copolymer mass was formed after 45
minutes. At this stage the agitator speed was increased in the range of 100 to 120 rpm,
15 to avoid agglomeration of reaction mass, and polymerization was continued at 75°C for
3 hours and at 85°C for 1 hour only. At this stage, the reaction mass was cooled to room
temperature then aqueous portion (⁓180mL) was siphoned out by vacuum filtration. The
second monomer feed containing 147.63 g of styrene and 17.37 g of commercially
available technical grade DVB solution which contains 9.9 g of DVB was added to the
20 cross-linked copolymer beads of the first component. Then, the monomer composition
of the cross-linked copolymer of the second component was allowed to imbibe in the
cross-linked copolymer beads of first component over a period of 2 hours. Then fresh
aqueous phase consisting of 540 mL of water, 0.81 g of HPEC and 2.7 g of DSP was
charged to the kettle. The polymerization reaction was continued under stirring (100 to
25 120 rpm) at 75°C for 3 hours then at 85°C for 3 hours and further at 95°C for 3 hours.
The content of the reaction kettle was then cooled to room temperature and beads of two
23
component cross-linked copolymer were washed until water washings showed no
foaming. The product was dried in an oven at 100°C for 8 hours. The yield of the two
component cross-linked copolymer beads based on total monomer charge was 68%
which indicates second component monomer conversion to polymer was incomplete.
5
Example 9
10
The experiment was carried out as described in Example 8, except that after the second
monomer feed was imbibed in the cross-linked copolymer beads already formed, the
polymerization was carried out at 75°C for 3 hours and then at 85°C for 3 hours. The
content of the reaction kettle was then cooled to room temperature. The two component
15 cross-linked copolymer beads was sticky in nature and had styrene smell. The beads
were washed with deionized water and dried in an oven at 100°C for 8 hours. The yield
of the two component cross-linked copolymers beads based on total monomer charge
was 70% indicating incomplete polymerization of the second monomer feed.
20
Example 10
25 The experiment was carried out as described in Example 8, except that after addition of
the monomer composition of first component followed by sticky stage, the
polymerization was carried out at 75°C for 1 hour and reaction was stopped, and aqueous
portion (⁓180mL) was siphoned out by vacuum filtration. Then second monomer
component containing 147.63 g of styrene and 17.37 g of commercially available
30 technical grade DVB solution containing 9.90 g of DVB and 0.165 g of BPO was added
24
and further continued reaction as mentioned in Example 8. The yield of the two
component cross-linked copolymers beads based on total monomer charge was greater
than 95%.
5
Example 11
10 The experiment was carried out as described in Example 8, except that after addition of
the monomer composition of first component followed by sticky stage, the
polymerization was carried out at 75°C for 3 hours and reaction was stopped, and
aqueous portion (⁓180mL) was siphoned out by vacuum filtration. Then monomer
composition of the second component containing 147.63 g of styrene and 17.37 g of
15 commercially available technical grade DVB solution containing 9.90 g of DVB and
0.165 g of BPO was added and further the reaction continued as mentioned in Example
8. The yield of the two component cross-linked copolymers beads based on total
monomer charge was greater than 95%.
20
Example 12
The experiment was conducted as described in Example 1, except that the protective
25 agent HPMC was replaced with HPEC in both first and second aqueous phase system.
The monomer composition of the second component was containing 134.2 g of styrene
and 15.8 g of commercially available technical grade DVB solution containing 9.006 g
of DVB and 0.6 g of BPO, polymerization reaction was continued as mentioned in
25
Example 1. The yield of the two component cross-linked copolymer beads was greater
than 95%.
Example 13
5
The experiment was conducted as described in Example 12, except that the second
monomer feed composition containing 214.7 g of styrene and 25.3 g of commercially
available technical grade DVB solution containing 14.42 g of DVB and 0.96 g of BPO
10 was added. Then, monomer composition of the cross-linked copolymer of the second
component was allowed to imbibe in the cross-linked copolymer beads of first
component over a period of 2 hours. Then fresh aqueous phase consisting of 840 mL of
water, 1.26 g of HPEC and 4.2 g of DSP was added to the reaction kettle. The
polymerization reaction was continued under stirring (100 to 120 rpm) at 75°C for 3
15 hours and then at 85°C for 3 hours and further at 95°C for 3 hours. The content of the
reaction kettle was then cooled to room temperature and beads of two component crosslinked copolymer were filtered and washed until water washings showed no foaming.
The product was dried in an oven at 100°C for 8 hours. The yield of the twocomponent
cross-linked copolymer beads based on total monomer charge was greater than 95%.
20
Example 14
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe, a
25 water bath, a temperature controller and a condenser, 600 g of water was added, followed
by 2.4 g of polyvinyl alcohol (PVA) (Grade: % Hydrolysis: 85 to 89 by weight and
26
viscosity 20 to 30 cPs at 20°C) 3 g of sodium lignosulfonate (SLS) (Grade: Viscosity of
50% w/v aqueous solution at 25°C about 15 to 25 cPs) and 18g of sodium chloride. The
agitator speed was set at 200-300 rpm after which the contents were heated to 75°C
over a period of 20 to 30 minutes then agitator speed was adjusted to 60 to 70 rpm. After
5 15 minutes, the first monomer feed containing 289.47 g of styrene and 10.53 g of
commercially available technical grade DVB solution containing 6.00 g of DVB and 1.2
g of BPO was added. The temperature was maintained at 75°C. A sticky copolymer mass
was formed after 45 minutes. At this stage to avoid agglomeration of reaction mass the
stirrer speed was increased to 100 – 120 rpm, and polymerization was continued for 3
10 hours. Then polymerization temperature was raised to 85°C continued for 3 hours and
then at 95°C for 3 hours. The reaction mass was cooled to room temperature then
aqueous portion was filtered and copolymer beads were washed and dried in an oven at
80 to 90°C until the moisture content of beads was less than 2%. 50 g of dried polymer
beads of first component were taken into reaction kettle, to this the second monomer
15 feed containing 85.96 g of styrene and 14.04 g of commercially available technical grade
DVB solution containing 8.00 g of DVB and 0.4 g of BPO was added. Then, monomer
composition of second component was allowed to imbibe in the cross-linked copolymer
beads of first component over a period of 2 hours. Then fresh aqueous phase consisting
of 300 mL of water, 1.2 g of PVA, 1.5 g of SLS and 9 g of sodium chloride was added
20 to the reaction kettle. The reaction mass was stirred at 100 - 120 rpm and polymerization
reaction continued at 75°C for 3 hours and then at 85°C for 3 hours and further at 95°C
for 3 hours. The contents of the reaction kettle were then cooled to room temperature.
The beads of two component cross-linked copolymer were washed with water until the
wash water did not show foaming. The product was dried in an oven at 100°C for 8
27
hours. The yield of the two component cross-linked copolymer beads based on total
monomer charge was greater than 95%.
5 Example 15
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe,a
10 water bath, a temperature controller and a condenser, 600g of water was added, followed
by 2.4 g of PVA, 3 g of SLS and 18 g of sodium chloride was added. The agitator speed
was set at 200-300 rpm after which the contents were heated to 75°C over a period of 20
to 30 minutes then agitator speed was adjusted to 60 to 70 rpm. After 15 minutes, the
first monomer feed containing 284.3g of styrene and 15.80 g of commercially available
15 technical grade DVB solution containing 9.006 g of DVB and 1.2 g of BPO was added.
The temperature was maintained at 75°C. A sticky copolymer mass was formed after 45
minutes. At this stage the stirrer speed was increased to 100 – 120 rpm, to avoid
agglomeration of reaction mass, and polymerization was continued for 3 hours. Then
polymerization temperature was raised to 85°C continued for 3 hours and then at 95°C
20 for 3 hours. The reaction mass was cooled to room temperature then aqueous portion
was filtered and copolymer beads were washed and dried in an oven at 80 to 90°C until
the moisture content of beads was less than 2%. 60 g dried polymer beads of first
component were taken into reaction kettle, to this the second monomer feed containing
99.36 g of styrene and 18.64 g of commercially available technical grade DVB solution
25 containing 10.625 g of DVB and 0.472 g of BPO was added. Then, monomer
composition of second component was allowed to imbibe in the cross-linked copolymer
28
beads of first component over a period of 2 hours. Then fresh aqueous phase consisting
of 400 mL of water, 1.6 g of PVA, 2 g of SLS and 12 g of sodium chloride was added
to the reaction kettle. The reaction mass was stirred at 100 - 120 rpm and polymerization
reaction continued at 75°C for 3 hours and then at 85°C for 3 hours and further at 95°C
5 for 3 hours. The contents of the reaction kettle were then cooled to room temperature.
The beads of two component cross-linked copolymer were washed with water until the
wash water did not show foaming. The product was dried in an oven at 100°C for 8
hours. The yield of the two component cross-linked copolymer beads based on total
monomer charge was greater than 95%.
10
Example 16
15
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe,a
water bath, a temperature controller and a condenser, 400 g of water was added, followed
by 0.6 g of HPEC and 2.0 g of DSP. The agitator speed was set at 200-300 rpm after
20 which the contents were heated to 75°C over a period of 20 to 30 minutes. Then agitator
speed was adjusted to 60 to 70 rpm. After 15 minutes, the first monomer feed containing
189.45 g of styrene and 10.55 g of commercially available technical grade DVB solution
containing 6.013 g of DVB and 0.8 g of BPO was added. The temperature was
maintained at 75°C. A sticky copolymer mass was formed after 45 minutes. At this stage
25 the stirrer speed was increased to 100 – 120 rpm, to avoid agglomeration of reaction
mass, and polymerization was continued for 3 hours. Then polymerization temperature
wasraised to 85°C continued for 3 hours and then at 95°C for 3 hours. The reaction mass
29
was cooled to room temperature then aqueous portion was filtered and copolymer beads
were washed and dried in an oven at 80 to 90°C until the moisture content of beads less
than 2%. 150 g of dried polymer beads of first component was taken into reaction kettle,
to this the second monomer feed containing 232.45 g of styrene and 32.55 g of
5 commercially available technical grade DVB solution containing 18.55 g of DVB and
1.06 g of BPO was added. Then, monomer composition of second component was
allowed to imbibe in the cross-linked copolymer beads of first component over a period
of 2 hours. Then fresh aqueous phase consisting of 1040 mL of water, 1.56 g of HPEC
and 5.2 g of DSP was added to the reaction kettle. The reaction mass was stirred at 100
10 - 120 rpm and polymerization reaction continued at 75°C for 3 hours and then at 85°C
for 3 hours and further at 95°C for 3 hours. The contents of the reaction kettle were then
cooled to room temperature. The beads of two component cross-linked copolymer were
washed with water until the wash water did not show foaming. The product was dried in
an oven at 100°C for 8 hours. The yield of the two component cross-linked copolymer
15 beads based on total monomer charge was greater than 95%.
Example 17
20
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe, a
water bath, a temperature controller and a condenser, 200 g of water was added, followed
by 0.35 g of HPEC, 1.65 g of tri sodium phosphate (TSP) and 0.47g of SLS. The agitator
25 speed was set at 200 - 300 rpm after which the contents were heated to 75°C over a
period of 20 to 30 minutes then agitator speed was adjusted to 60 to 70 rpm. After 15
minutes, the first monomer feed containing 111.44 g of styrene and 6.21g of
30
commercially available technical grade DVB solution containing 3.54 g of DVB and
0.47g of BPO was added. The temperature was maintained at 75°C. A sticky copolymer
mass was formed after 45 minutes. At this stage the stirrer speed was increased to 100 –
120 rpm, to avoid agglomeration of reaction mass, and polymerization was continued
5 for 3 hours. Then polymerization temperature was raised to 85°C continued for 3 hours
and then at 95°C for 3 hours. The content of the reaction kettle was cooled to room
temperature and then aqueous portion (⁓180mL) was siphoned out. The second
monomer feed containing 174.0 g of styrene and 20.5 g of commercially available
technical grade DVB solution containing 11.68 g of DVB and 0.78 g of BPO was added
10 to the cross-linked copolymer beads of the first component. Then, monomer composition
of the cross-linked copolymer of the second component was allowed to imbibe in the
cross-linked copolymer beads of first component over a period of 2 hours. Then fresh
aqueous phase consists of 510mL of water, 0.9 g of HPEC, 4.2 g of TSP and 1.2 g of
SLS was added to the reaction kettle. The reaction mass was stirred at 100-120 rpmand
15 polymerization reaction continued at 75°C for 3 hours and then at 85°C for 3 hours and
further at 95°C for 3 hours. The content of the reaction kettle was then cooled to room
temperature and beads of two component cross-linked copolymer were filtered and
washed until water washings showed no foaming. The product was dried in an oven at
100°C for 8 hours. The yield of the two component cross-linked copolymer beads based
20 on total monomer charge was greater than 95%.
Example 18
31
To a one litre, four-neck reaction kettle equipped with a stirrer, a thermocouple probe,a
water bath, a temperature controller and a condenser, 200 g of water was added, followed
by 0.35 g of HPEC and 1.18 g of DSP. The agitator speed was set at 200 - 300 rpm after
which the contents were heated to 75°C over a period of 20 to 30 minutes then agitator
5 speed was adjusted in the range of 60 to 70 rpm. After 15 minutes, the first monomer
feed containing 111.44 g of styrene and 6.21g of commercially available technical grade
DVB solution containing 3.54 g of DVB and 0.47g of BPO was added. The temperature
was maintained at 75°C. A sticky copolymer mass was formed after 45 minutes. At this
stage the stirrer speed was increased in the range of 100 to 120 rpm, to avoid
10 agglomeration of reaction mass, and polymerization was continued for 3 hours. Then
polymerization temperature was raised to 85°C continued for 3 hours and then at 95°C
for 3 hours. The content of the reaction kettle was cooled to room temperature and then
aqueous portion (⁓175 mL) was siphoned out. The second monomer feed containing
177.4 g of styrene and 17.1g of commercially available technical grade DVB solution
15 containing 9.75 g of DVB, 2.06 g of 1,7-octadiene and 0.78 g of BPO was added to the
cross-linked copolymer beads of first component. Then, monomer composition of the
cross-linked copolymer of the second component to was allowed to imbibe in the crosslinked copolymer beads of first component over a period of 2 hours. Then fresh aqueous
phase consisting of 505 mL of water, 0.9 g of HPEC and 2.98 g of DSP was added to
20 the reaction kettle. The reaction mass was stirred at 100-120 rpm and polymerization
reaction continued at 75°C for 3 hours and then at 85°C for 3 hours and further at 95°C
for 3 hours. The content of the reaction kettle was then cooled to room temperature and
beads of two component cross-linked copolymer were filtered and washed until water
washings showed no foaming. The product was dried in an oven at 100°C for 8 hours.
32
The yield of the two component cross-linked copolymer beads based on total monomer
charge was greater than 95%.
5 Example 19
The experiment was carried out as described in Example 18, except that the second
10 monomer feed was composed of 177.4 g of styrene and 17.1 g of commercially available
technical grade DVB solution containing 9.75 g of DVB, 2.06 g of trivinyl cyclohexane
(TVCH), 0.78 g of BPO and 0.1 g of dicumyl peroxide (DCP). After the polymerization
reaction, the contents of the reaction kettle were cooled to room temperature and the
beads of two component cross-linked copolymer were washed with water until water
15 washings showed no foaming. The product was dried in an oven at 100°C for 8 hours.
The yield of the two component cross-linked copolymer beads based on total monomer
charge was greater than 95%.
20 Example 20
To a two litre, four-neck reaction kettle, equipped with a stirrer, a thermocouple probe,
25 a water bath, a temperature controller and a condenser, 920 g of water was added,
followed by 0.75 g of HPEC and 5 g of DSP. The agitator speed was set at 200 - 300
rpm after which the reaction mass was heated to 75°C over a period of 20 to 30 minutes
then agitator speed was adjusted to 60 to 70 rpm. After 15 minutes, the first monomer
feed containing 484.2g of styrene and 15.8 g of commercially available technical grade
30 D V Bsolution containing 9 g of D V Band 2.0 g of BPO was added. The temperature
33
was maintained at 75°C. A sticky copolymer mass was formed after about 80 minutes.
At this stage the stirrer speed was increased to 100 - 120 rpm, to avoid agglomeration of
reaction mass, and polymerization was continued for 3 hours. Then polymerization
temperature was raised to 85°C continued for 3 hours and then at 95°C for 3 hours. The
5 reaction mass was then cooled to room temperature. The beads were filtered and washed
with water until the wash water did not show foaming. The beads were dried in oven
between 80 and 85°C, till moisture content was less than 2%. The yield of copolymer
beads based on total monomer charge was greater than 95%.
10
Example 21
15 Monomer feed composition of the second component consisting of 20.6g of styrene,
10.85g of commercially available technical grade DVB solution containing 6.2 g of
DVB, 174.55 g of methyl methacrylate (MMA) and 0.72 g of AIBN was added to 100 g
copolymer beads of Example 20. During next 2 hours the cross-linked copolymerbeads
already formed, fully imbibed the monomer composition of the second component. At
20 this point, the aqueous phase consisting of 800mL of water, 2.4 g of hydroxy
ethylcellulose (HEC) (Grade: Viscosity of 2% w/v aqueous solution at 25°C is about
5000 to 5800 cPs) and 2.4 g of carboxy methylcellulose (CMC) (Grade: Viscosity of 1%
w/v aqueous solution at 25°C about 40 to 60 cPs), 1.2 g of SLS and 40 g of sodium
chloride was charged in to the reaction kettle. The polymerization was continued at 75°C
25 for 3 hours and then at 85°C for 3 hours and further at 95°C for 3 hours. Then the reaction
mass was cooled to room temperature. The beads of two component cross-linked
copolymer were washed with water until the wash water did not show foaming. The
34
beads were dried in an oven at 85°C for 8 hours, resulting in greater than 95% yield
based on total monomer charge.
5 Example 22
Monomer feed composition of the second component consisting of 84 g of styrene, 12.6
10 g of commercially available technical grade DVB solution containing 7.2 g of DVB,
143.4 g of MMA and 0.84 g of AIBN was added to 100 g of cross-linked copolymer
beads obtained in Example 20. During next two hours the cross-linked copolymers beads
already formed, fully imbibed the monomer feed composition of the second component.
At this point, the aqueous phase consisting of 800 mL of water, 2.4g of HEC, 2.4 g of
15 CMC, 1.2 g of SLS and 40 g of sodium chloride was charged in to the reaction kettle.
The polymerization was continued at 75°C for 3 hours and then at 85°C for 3 hours and
further at 95°C for 3 hours. Then the reaction mass was cooled to room temperature. The
beads of two component cross-linked copolymer were washed with water until the wash
water did not show foaming. The beads were dried in an oven at 80-85°C for 8 hours,
20 resulting in yield of copolymer beads greater than 95% based on total monomer charge.
Example 23
25
Monomer feed composition of the second component consisting of 99 g of styrene, 11.58
g of commercially available technical grade DVB solution containing 6.6 g of DVB,
109.4 g of MMA and 0.76 g of AIBN was added to 100 g copolymer beads obtained in
30 Example 20. During next 2 hours these cross-linked copolymer beads already formed
35
fully imbibed the monomer feed composition of the second component. At this point,
the aqueous phase consisting of 800mL of water, 2.4 g of HEC, 2.4 g of CMC, 1.2 g of
SLS and 40 g of sodium chloride was added. The reaction mass was held at 75°C for 3
hours and then at 85°C for 3 hours and further at 95°C for 3 hours. Then the reaction
5 mass was cooled to room temperature. The beads of two component cross-linked
copolymer were washed with water until the wash water did not show foaming. The
beads were dried in an oven at 80-85°C for 8 hours, resulting in greater than 95% yield
based on total monomer charge.
10
Example 24
15 Monomer feed composition of the second component consisting of 120 g of styrene,
12.6 g of commercially available technical grade DVB solution containing 7.2 g of DVB,
107.4 g of MMA and 0.84 g of AIBN was added to 100 g of cross-linked copolymer
20 beads synthesized as described in Example 20. During next 2 hours the cross-linked
beads already formed fully imbibed the monomer feed composition of the second
component. At this point, the aqueous phase consisting of 800 mL of water, 2.4 g of
HEC, 2.4 g of CMC, 1.2 g of SLS and 40 g of sodium chloride was added. The
polymerization was carried out at 75°C for 3 hours and then temperature was raised to
25 85°C and maintained for 3 hours. Further temperature was raised to 95°C and maintained
for 3 hours. Then the reaction mass was cooled to room temperature. The beads of two
component cross-linked copolymer were washed with water until the wash water did not
show foaming. The beads were dried in an oven at 85°C for 8 hours, resulting in greater
than 95% yield based on total monomer charge.
36
Example 25
5 Soxhlet extraction of two component cross-linked copolymers in the bead form.
To a round bottom flask equipped with an oil bath, Soxhlet apparatus and reflux
10 condenser, 200 mL of toluene was added to the round bottom flask and 10g of polymer
beads (W1) to the thimble of the Soxhlet apparatus. The flask was heated so that toluene
refluxed at 112 ± 2°C. During reflux, polymer beads were extracted continuously with
toluene over a period of 8 hours. Then the flask was cooled to room temperature,
polymer beads were collected and washed with methanol. Then polymer beads were
15 transferred into a pre-weighed Petri-dish, pre-dried at room temperature then dried in an
oven at 110 ± 2°C till it attained a constant weight, this weight was recorded as dry
weight of polymer beads (W2). Percent weight loss of extracted polymer beads was
calculated by following formula. The results are tabulated in Table 1.
Weight loss (%) = [(W1 – W2) X 100] / W1
20
Table1: Polymer beads weight loss after solvent extraction
25
Example No Weight loss (%)
Example 1 2.252
Example 2 5.902
Example 3 3.764
Example 4 2.215
Example 5 2.2015
Example 6 2.322
Example 7 2.174
37
Example 26
5 Swelling behaviour of two component cross-linked copolymers in toluene
In to a 100 mL measuring cylinder with lid 80 mL of toluene was taken and 10 g of dry
10 polymer beads were gently added to toluene and covered with lid. Then the measuring
cylinder was gently tapped and kept on the horizontal surface, recorded volume of
polymer beads (VT) for every 5 minutes intervals till 1 hour; every 15 minutesintervals
till 6 hrs; then at every 6 hours intervals till 100th hour of swelling time. The maximum
swelling volume is recorded as VM, then measured swelling in percent (Swelling, %)
15 by following formula. Figure 1 shows plotted curves of swelling pattern of copolymer
beads synthesized by current invention.
Swelling (%) = [VT X 100] / VM
Synthesis of strong acid cation exchange resins
20
Example 27
25
To a one litre, four-neck sulphonation glass kettle equipped with anchor stirrer, a
thermometer pocket, heating mantle, a temperature controller and a water circulated
condenser, was added 100 g of dried styrene-DVB two component copolymer beads
30 obtained in Example 1. Then 400 mL of sulfuric acid (Purity: 93 to 95%) was charged
to the kettle. The stirrer speed was adjusted to about 200 rpm. The reaction mass was
heated slowly to 110°C ± 2°C and maintained for 6 hours. The reaction mass was then
cooled to room temperature. Then the sulfonated resin was separated from excess of
38
sulfuric acid by drawing out sulfuric acid from the reaction mass. The sulfonated resin
mass was subjected to programmed hydration process in which the resin mass was
treated with sulfuric acid solutions of concentrations of 85%, 78%, 65%, 45%, 30%,
25% and 15 % w/w. 250 mL aliquot of the 85% sulfuric acid solution was added to
5 sulphonated mass and stirred at room temperature for 30 to 45 minutes. There after the
aliquot was siphoned off and the procedure was repeated with next aliquot of 78%
sulfuric acid concentration. The procedure was continued till the last wash was with 15
% w/w Sulphuric acid solution. Finally, the sulfonated resin was washed with deionized
water till wash water pH was neutral. The strong acid cation exchange resin yield was
10 about 400mL. The resin had 51% moisture, total exchange capacity (TEC) 1.8 eq/Land
dry weight capacity 4.4 milli equivalents per gram (meq/g). The whole beads countwas
more than 95%.
15 Procedure for whole bead count measurement
The wet resin sample was spread into a Petri-dish and observed under optical
microscope. The number of total beads visible was counted and also the number of
20 cracked / broken beads was counted. Then the Petri-dish position was changed and
another portion of the resin was viewed and the procedure repeated. About 25 to 30
observations were made with different aliquots taken from same resin sample, an
average crack or broken beads in percent number was calculated by following formula.
(Number of cracked + broken beads)X 100
25 Cracked / broken beads (%) =
---
Number of total beads (cracked + broken + intact beads)
39
Whole bead count (%) = 100 - (% cracked / broken
beads) Dry resin swelling study in water
The resin was dried at 1000C in oven to obtain moisture free resin. About 10 g accurately
weighed dry resin was slowly added to a graduated measuring cylinder of 50 mL
5 capacity, containing deionised water. The cylinder was tapped gently to settle the resin.
After 5 minutes volume of the resin was noted. Thereafter, the volume of the resin was
noted at every five minutes up to 2 hours and then after 24 hours. Since there was no
change in volume of the resin after 20 minutes, readings between 20 minutes and 24 hrs
are not included in Table 2.
10 % Swelling ratio (v/w) = (Swollen volume of resin in water X100) / dry weight of resin
(w)
Table 2: Dry resin swelling
Resin Weight of
dry resin, g
Dry resin
swelling,
mL
Swelling Time in minutes
5 10 15 20 1440
Resin volume in mL
Indion 225H 10.0144 13 22 24 26 26 26
Example 27 10.0063 12 20 22 24 24 24
15
Example 28
20 The sulfonation reaction was conducted as described in Example 27, with cross-linked
copolymer beads obtained in Example 1. The sulfonation time was restricted to 1 hour.
During hydration step, the bead surface was destroyed, leading to uneven and highly
cracked resin beads as seen under optical microscope.
40
Example 29
5 The sulfonation reaction was conducted as described in Example 27, with cross-linked
copolymer beads synthesized as described in Example1. The sulfonation time was
restricted to 2 hours. The product had reddish brown colour and sulfonated resin yield
was about 300 mL. The resin had about 41.3% moisture, and showed TEC of 1.56 eq/L
and dry weight capacity 3.21 meq/g, and whole beads count 90%.
10
Example 30
15
The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained in Example 1. The sulfonation time was restricted to 3 hours. The resin
had reddish brown colour and sulfonated resin yield was about 340mL. The resin had
about 42.7% moisture, and showed TEC 1.68 eq/L, dry weight capacity 3.36 meq/g, and
20 whole beads count 95%.
Example 31
25
The sulfonation reaction was conducted as described in Example 27, with cross-linked
copolymer beads obtained in Example1.The sulfonation time was restricted to 4 hours.
The resin had reddish brown colour and the sulfonated resin yield was about 360 mL.
30 The resin had about 44.8% moisture, TEC 1.72 eq/L and dry weight capacity 3.84 meq/g.
The whole beads count was 95%.
41
Example 32
5
The sulfonation reaction was conducted as described in Example 27, using cross-linked
copolymer beads obtained in Example 2. The resin had 61.2 % moisture, TEC 1.26 eq/L
and dry weight capacity 3.36 meq/g. The whole beads count was 94%.
10
Example 33
15 The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer beads obtained in Example 8. The resin had 57.2% moisture, TEC 1.33 eq/L
and dry weight capacity 3.46 meq/g. The whole beads count was 94%.
20 Example 34
The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
25 copolymer beads obtained in Example 9. The resin had about 58.5% moisture, TEC 1.32
eq/L and dry weight capacity 3.42 meq/g. The whole beads count was 94%.
Example 35
30
The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer beads obtained in Example 10. The resin had about 49.5% moisture, TEC
35 1.80 eq/L and dry weight capacity of 4.42 meq/g. The whole beads count was 95%.
42
Example 36
5 The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer beads obtained in Example 11. The resin had about 50.8% moisture, TEC
1.82 eq/L and dry weight capacity of 4.56 meq/g. The whole beads count was 95%.
10
Example 37
15 The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer beads obtained from Example 1, except that the amount of sulfuric acid used
was 100mL. The resin yield was 290 mL. The resin had about 41% moisture, TEC 1.56
eq/L and dry weight capacity 3.49 meq/g. The whole beads count was 70%.
20
Example 38
25 The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer beads obtained in Example 1 except that the sulfuric acid quantity used was
200 mL. The resin yield was 360 mL. The resin had about 49.81% moisture, TEC was
1.70 eq/L and dry weight capacity was 4.21 meq/g. The whole beads count was 80%.
30
Example 39
35
The sulfonation reaction was conducted as mentioned in Example 27, using cross-linked
copolymer obtained in Example 1 except that the amount of sulfuric acid used was 300
43
ml. The resin yield was 410 mL, had about 49.71% moisture, TEC 1.72 eq/L and dry
weight capacity 4.49 meq/g. The whole beads count was 95%.
5 Example 40
The sulfonation reaction was conducted as mentioned in Example 27, with cross-linked
10 copolymer beads obtained from Example 1except that the amount of sulfuric acid used
was 400mL and purity of sulfuric acid was 98% w/w. The resin yield was 450 mL, had
about 50.87% moisture, TEC of 1.85 eq/L and dry weight capacity of 4.55 meq/g. The
whole beads count was 95%.
15
Example 41
20 The sulfonation reaction was conducted as mentioned in Example 27, with cross-linked
copolymer beads obtained from Example 1 except that the amount of sulfuric acid used
was 600mL and purity of sulfuric acid was 94% w/w. The sulfonation reaction was
stopped after 2 hours. The resin yield was 320 mL, had about 41.72% moisture, TECof
1.56 eq/L and dry weight capacity of 3.49 meq/g.
25
Example 42
30
The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 12. The resin had reddish brown colour and sulfonated
44
resin yield was about 430mL. The resin had about 49.9% moisture, and showed TEC
1.64 eq/L, dry weight capacity 4.3 meq/g, and whole beads count was 85%.
5
Example 43
10
The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 13. The resin had reddish brown colour and sulfonated
resin yield was about 460 mL. The resin had about 52.65% moisture, and showed TEC
1.60 eq/L, dry weight capacity 4.36 meq/g, and whole beads count was 80%.
15
Example 44
20
The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 14. The resin had reddish brown colour and sulfonated
resin yield was about 450 mL. The resin had about 56.56 % moisture, TEC 1.72 eq/L,
25 dry weight capacity 4.41 meq/g, and whole beads count was 80 %.
Example 45
30
The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 15. The resin had reddish brown colour and sulfonated
resin yield was about 450 mL. The resin had about 51.53 % moisture, TEC 1.72 eq/L,
35 dry weight capacity 4.30 meq/g, and whole beads count was 70%.
45
Example 46
5 The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 16. The resin had reddish brown colour and sulfonated
resin yield was about 390 mL. The resin had about 48.18 % moisture, TEC 1.8 eq/L, dry
weight capacity 4.54 meq/g, and whole beads count was 90 %.
10
Example 47
15 The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 18. The resin had black colour and sulfonated resin yield
was about 450mL. The resin had about 53.86% moisture, TEC 1.5 eq/L, dry weight
capacity 4.27 meq/g, and whole beads count was 85 %.
20
Example 48
25 The sulfonation reaction was conducted as described in Example 27, with copolymer
beads obtained from Example 19. The resin had black colour and sulfonated resin yield
was about 460 mL. The resin had about 53.81 % moisture, TEC 1.34 eq/L, dry weight
capacity 4.17 meq /g, and whole beads count was 75 %.
46
Example 49
5 Chloromethylation reaction was carried out in a glass kettle provided with an anchor
type glass stirrer, a thermometer pocket and a water condenser. The reaction kettle was
placed in a water bath, 168 g 50 % formaldehyde solution in methanol (w/w). 15 g
methanol, 40 g methylal, 46 g water and 10 g ferric chloride catalyst (40% solution in
water) were placed into reaction kettle. 180mL chlorosulfonic acid (CSA) was slowly
added through the dropping funnel over a period of 5- 6 hours at 38- 400
10 C. Then, 100 g
dry copolymer beads obtained in Example 21 were charged in to the reaction kettle under
stirring at 200C. Chloromethylation reaction was conducted at 38-400C for 6 hours and
then reaction mass was cooled to 20 -250C. The reaction mass was quenched with three
lots of 300 mL methanol, to decompose unreacted CMME. Finally the chloromethylated
15 resin was washed with dilute alkali solution then with water till the pH of the wash water
was neutral.
Amination was conducted in a reaction kettle provided with an anchor type glass stirrer,
20 thermometer pocket and condenser. Chloromethylated resin beads of 100 mL transferred
into the reaction kettle along with water. Excess water was removed from the
chloromethylated beads. Then 200 mL of methylal was added into the reactor followed
by about 2 mL of caustic lye to maintain pH in the range of 10-12. The mixture was
stirred and cooled to 250C and 100 mL of trimethyl amine (30% aqueous solution of
25 TMA) was added using an addition funnel over a period of 30 to 45 minutes. After
mixing the contents at 25-300C for 30 minutes, reaction mass was heated to 42- 45 0C
and the reaction was continued for 6 hours. Then the mixture was heated to 800C and
47
methylal was distilled off from the reaction mass. The reaction mass was cooled to room
temperature and 50mL of 7% (w/v) hydrochloric acid solution was added to the reaction
mass. The reaction mass was stirred for another half an hour and then filtered, washed
with deionized water. Obtained product yield of 290 mL of aminated resin by this
5 process. The resin was tested for its properties as listed in Example 52.
Example 50
10
The chloromethylation and amination reactions were conducted as mentioned in
Example 49 except the polymer beads of Example 22 were used for the synthesis of
anion resin. The resin properties were tested as listed in Example 52.
15
Example 51
20
The chloromethylation and amination reactions were conducted as mentioned in
Example 49 except the polymer beads of Example 23 were used for the synthesis of
anion resin. The resin properties were tested as listed in Example 52.
25
Example 52
30 Chloromethylation reaction was carried out in a glass reaction kettle provided with an
anchor type glass stirrer, thermometer pocket and water condenser. The reaction kettle
was placed in a water bath. To this was added 75 g of ethylene dichloride, 70 g of
methanol – formaldehyde solution (50%, w/w), 6.5 g of methanol, 12.6 g of methylal,
48
11g of water and 7.5 g of ferric chloride catalyst (40% solution). Then 50 mL of
chlorosulfonic acid (CSA) was slowly added through dropping funnel over a period of
5- 6 hours at 38- 400C. Then, 100 g of dry copolymer beads synthesized as described in
Example 24 was charged into the reactor kettle under stirring at about 200C. The reaction
was conducted at 57±20C for 6 hours and then reaction mass was cooled to 18 – 250
5 C.
To decompose the unreacted CMME, the reaction mass was quenched with methanolin
three lots of 150 mL each. Finally the chloromethylated resin was washed with 300 ml
of 1% alkali solution (w/v) followed by water wash till the pH of wash water to be
neutral.
10
The chloromethylated resin prepared above was aminated with trimethyl amine (TMA).
Aminaiton reaction was conducted as mentioned in Example 49. The resin was further
tested for its properties and results are tabulated in Table 3.
15 Table 3: Characteristics of strong base anion exchange resins*
Example
No
Moisture, % TEC, eq/L DWC, meq/g Whole beads, %
49 47.53 0.74 1.78 greater than 90
50 50.0 0.75 2.08 greater than 90
51 54.78 0.87 2.68 greater than 85
52 52.4 1.02 3.01 greater than 85
* As per ISI test method 7330-1988
Resin swelling ratio in water
20
The resins (Example 51 and 52) were dried at 700C in an oven to obtain moisture free
resin. About 10g accurately weighed dry resin was slowly added to a graduated
measuring cylinder of 50mL capacity, containing deionised water. The cylinder was
tapped gently to settle the resin. After 5 minutes, the volume of the resin was noted and
49
thereafter at every five minutes up to 2 hours and finally after 24 hrs. Since there were
no volume changes after twenty minutes, the values in between are not listed in Table 4.
% Swelling ratio (v/w) = (Swollen volume of resin in water X 100) / dry weight of resin
(w)
5 Table 4: Dry swelling data of SBA resins
Resin Resin
weight g
Dry resin
volume ml
Swelling time in minutes
5 10 15 20 1440
Resin volume in mL
Indion GS
300
10.0032 16 mL 28 28 28 28 28
Example 51 10.0092 15 mL 27 27 27 27 27
Example 52 10.0381 15 ml 29 29 29 29 29
Synthesis of weak acid cation exchange resin
10
Example 53
15
To a one litre, four-neck reaction kettle equipped with a stirrer, thermocouple probe,
water bath, temperature controller and condenser, were added 400 g of water followed
by 1.2 g of hydroxy ethylcellulose (HEC) (Grade- viscosity of 2% aq. solution at 250C
20 is about 5000 – 5800 Cps). After dissolution of HEC, 1.2 g of carboxy methylcellulose
(CMC) (Grade- viscosity of 1% aqueous solution at 250C is about 40-60 cPs) was added
and mixed together. Then 0.6 g of sodium lignosulfonate (Grade- viscosity of 50%
aqueous solution at 250C is about 15-25 cPs) followed by 130 g of sodium chloride was
added. Temperature of this mixture was raised to 60 to 650C. The stirrer speed was set
25 between 200-300 rpm. The stirring speed was then adjusted to 60-70 rpm. After 15
50
minutes, the first monomer feed containing 20 g of methacrylic acid, 173 g of methyl
acrylate and 7.1 g commercially available technical grade DVB solution containing
4.05g DVB and 0.6 g benzoyl peroxide (BPO) and 0.6 g azobis-isobutyronitrile (AIBN)
was added. The reaction kettle was heated to 65°C. After 45 to 50 minutes, sticky
5 copolymer mass was formed. At this stage the stirrer speed was increased to 100-
120rpm, to avoid agglomeration, and polymerization was continued for 3 hours at 65°C.
The temperature was then maintained at 75°C and polymerization was continued for 3
hours, and then at 85°C for 3 hours and then at 95°C for another 3 hours. The contents
of the reaction kettle were then cooled to room temperature and the beads of copolymer
10 were washed with deionized water till the wash water was free from foam, and dried in
an oven at 100°C for 6-8 hours. The yield of the cross-linked copolymer beads based on
monomer charge was 95%.
15 The second monomer solution was prepared by mixing 46.2 g of methyl methacrylate,
4.62 g of methacrylic acid, 76.54 g of methyl acrylate and 4.64 g of commercially
available technical grade DVB solution containing 2.64 g of DVB and 0.57 g of AIBN.
This monomer mixture was added to 50 g of cross-linked copolymer beads already
20 formed in the first step. Over the next two hours the second monomer solution was
imbibed in the cross-linked copolymer beads already formed. At this point, the aqueous
phase consisting of 600 mL of water,1.8 g of hydroxy ethyl cellulose (HEC) (Gradeviscosity of 2% aqueous solution at 250C is about 5000 – 5800 Cps), 1.8 g carboxy
methylcellulose (CMC) (Grade- viscosity of 1% aq.solution at 250C is about 40-60 cPs),
1.0 g of sodium lignosulfonate (SLS) (Grade- viscosity of 50% aqueous solution at 250
25 C
is about 15-25cPs) and 210 g of sodium chloride was charged in the reaction kettle. The
51
reaction mass was stirred at 100-120 rpm and polymerization reaction was continued at
65°C for 3 hours and then at 75°C for 3 hours and further at 85°C for 2 hours. 200 g of
46% caustic lye was added to the reaction kettle and the heating was continued at 850C
for 3 hours and then at 950C for 3 hours. The reaction mass was then cooled to room
5 temperature, filtered and washed with demineralized water. The yield of the weak acid
cation exchange resin obtained was approximately 700 mL. The moisture content ofthe
product was 45%, total exchange capacity was 2.76 eq/L and dry weight capacity was
6.46 meq/g. The product showed 120% swelling when converted from H to Na form.
10
Example 54
15
This experiment was carried out as in Example 53, except that second monomer solution
comprising 60.2 g of methyl methacrylate, 6.25 g of methacrylic acid, 37.65 g of methyl
acrylate, 6.25 g of hydroxy ethyl methacrylate (HEMA), and 7.65 g of commercially
available technical grade DVB solution containing 4.36 g of DVB and 0.51 g of AIBN
20 was added to the 50 g cross-linked copolymer beads already formed in the first step.
Over the next two hours the second monomer solution was imbibed in the cross-linked
copolymer beads already formed in the first step. At this point, the aqueous phase
consisting of 600 mL of water, 1.8 g of HEC, 1.8 g of CMC, 1.0 g of sodium
lignosulfonate, and 120 g of sodium chloride was charged into the reaction kettle. The
25 reaction mass was stirred at 100-120 rpm and polymerization reaction was continued at
65°C for 3 hours and then at 75°C for 3 hours and further at 85°C for 2 hours. After that
200 g 46% (w/v) caustic lye was added and the heating continued at 850C for 3 hours
and then at 950C for 3 hours. The reaction mass was cooled to room temperature, filtered
52
and washed with demineralized water. The yield of the weak acid cation exchange resin
obtained was approximately 490mL. The product had 38% moisture, TEC 1.95 eq/L and
dry weight capacity 5.41 meq/g. The product had swelling of 86% when converted from
H to Na form.
5
Example 55
10
Performance evaluation of strong acid cation (SAC) resin. The SAC resin product
obtained as described in Example 27 was evaluated for performance in water
demineralization and water softening applications. The procedure followed was as per
ASTM Designation: D 2187–94 (Reapproved 2004). The performance of the resin made
15 was compared with performance of commercial resin in H form for water
demineralization and Na form for water softening applications.
Procedure
The procedure consisted of first preparing a resin column as depicted in the Figure 2.
20
A synthetic feed solution of 1000 L was prepared by dissolving accurately weighed
quantities of 132.3 g of calcium chloride dihydrate, 182.7g of magnesium chloride
hexahydrate and 140.4 g of sodium chloride. These salts were dissolved and diluted to
about 10L in a polyethylene container. All of these salt solutions were further gently
25 added to synthetic feed water tank and diluted to 1000L with deionized water. The
synthetic feed water quality parameters are tabulated in Table 5.
Table 5: The synthetic feed water quality parameters for demineralization application
Parameter Concentration
Total Hardness 180 ppm as CaCO3
53
Calcium hardness 90 ppm as CaCO3
Magnesium
hardness
90 ppm as CaCO3
Sodium 120 ppm as CaCO3
Total Cations 300 ppm as CaCO3
Na/Total Cation % 40
Four glass columns were filled with 300 mL each of resin prepared in Example 27 and
another four columns with 300 mL of commercial resin (Indion 225H) comprising single
5 component cross-linked copolymer in H form.
The feed solution prepared above was passed through the columns at a flow rate of 20
bed volume (BV)/ hour in gravity flow mode. The water leaving the column outlet was
10 checked for every 30 minutes for sodium content. The analysis was conducted by flame
photometer method using sodium ion filter.
The experiment was stopped, when the concentration of sodium in the column outlet
15 reached to 0.5 ppm. Total feed solution passed through the column was noted and
operating exchange capacity (OEC) of the resin was calculated using following formula.
(Total cations, ppm as CaCO3) X (Output water quantity in
L) OEC (g/CaCO3/L)=
20 .
Resin volume in L X 1000
The first cycle is known as conditioning run. After conditioning run, the resin was
25 regenerated by passing 5% w/v hydrochloric acid (HCl) solution through resin bed in
counter current mode with 30 minutes contact time. The resin was rinsed with deionized
water to remove residual acid from resin bed. The volume of water required to rinse the
resin of Example 27 was 25 to 30% lower than that required for the commercial resin.
54
Subsequently three demineralization cycles were similarly conducted. The performance
of the resin was evaluated at different regeneration levels of 40 g/L, 50 g/L, 60 g/L and
70 g/L of resin using 5% w/v HCl solution. These results are tabulated in Table 6 and
Table 7.
5 Table 6: Operating exchange capacity in demineralization
applications
Regeneration
Level, g/L
Resin from Example 27
OEC g as CaCO3 /L resin
Commercial resin Indion
225H OEC g as CaCO3 /L
resin
% OEC
enhancement
40 39.38 35.71 10.28
50 49.85 43.83 13.73
60 54.42 46.07 18.12
70 62.72 53.08 18.16
Table 7: SAC resin performance in demineralization applications
10
Regeneration
Level g/L
Resin from Example 27
% OEC/TEC ratio based on
TEC as 90.0 g as CaCO3/L
resin
Commercial resin Indion 225H %
OEC/TEC ratio based on TEC as
95.0 g as CaCO3/L resin
40 43.75 37.59
50 55.39 46.14
60 60.47 48.49
70 69.69 55.87
Example 56: Operating exchange capacity: Water softening applications
15
A synthetic feed solution of 1000L was prepared by dissolving accurately weighed
quantities of 220.5 g of calcium chloride dihydrate, 304.5 g of magnesium chloride
20 hexahydrate and 234.0 g of sodium chloride, these salts were dissolved and diluted to
about 10L in to separate poly containers. All of these salt solutions were further gently
added to synthetic feed water tank and diluted to 1000L with deionized water. The
synthetic feed water quality parameters are tabulated in Table 8.
55
Table 8: The synthetic feed water quality parameters used for water softening application
Parameter Concentration
Total Hardness 300 ppm as CaCO3
Calcium hardness 150 ppm as CaCO3
Magnesium hardness 150 ppm as CaCO3
Sodium 200 ppm as CaCO3
Total Cations 500 ppm as CaCO3
Na/Total Cation % 40
5
Example 27 resin about 500 mL was first converted to sodium (Na+) form by the
following procedure.
10 The conversion of hydrogen (H+) form resin to Na+ form was carried out in a glass
reactor provided with an anchor type glass stirrer, a thermometer pocket. 500ml of H+
form resin was charged in the glass reactor, keeping minimum water (about 400 to
500mL) for stirring. A 4% w/v sodium hydroxide solution about 2.5 BV against the resin
taken for conversion to be added slowly in 60 to 90 minutes under stirring. The
15 temperature was maintained below 40°C throughout the neutralization reaction. After
complete addition of the sodium hydroxide solution the pH of mother liquor was
confirmed to be alkaline. The stirring was continued for next 30 minutes while pH was
monitored. Then the resin was washed with water till wash water pH was between 6.5
and 8.0.
20 A glass column was filled with 300mL of Na+ form converted resin of Example 27.
A second column was filled with 300mL of commercial resin which was a single
component cross-linked copolymer in Na+ form.
56
The feed solution prepared above was passed through the columns at a flow rate of 20
BV / hour in gravity flow mode. Water exiting at the column outlet was intermittently
checked for total hardness content for every 30 minutes. The total hardness of water
was measured by standard EDTA test method according to AWWA analytical test
5 method.
The experiment was stopped, when the concentration of total hardness in column out let
exceeded 1.0 ppm. Total feed solution passed through the column was noted and OEC
10 of the resin was calculated.
The first cycle is known as conditioning cycle. Subsequently the resin was regenerated
by passing 10% sodium chloride solution (w/v) through resin bed in co-current mode
15 with 30 minutes contact time. Thereafter the resin was rinsed with deionized water to
remove residual sodium chloride from resin bed. The volume of water required to rinse
the resin was 20 to 25 % lower when compared to that for conventional commercial
resin. Subsequently seven softening cycles were similarly conducted. The results are
tabulated in Table 9.
20 Table 9: SAC resin utility in water softening application
Resin Example 27 in Na+ form Commercial resin Indion 225Na
form
Cycle
OEC,
g/Las
CaCO3
TH
leakage,
ppm
% OEC/TEC
(95.0 g as
CaCO3/L in
Na+ form)
OEC,
g/Las
CaCO3
TH
leakage,
ppm
% OEC /
TEC
(100.0g as
CaCO3/L in
Na+ form)
1 58.25 <1.0 61.31 56.84 <1.0 56.84
2 57.54 <1.0 60.56 56.84 <1.0 56.84
3 58.25 <1.0 61.31 57.54 <1.0 57.54
57
4 58.25 <1.0 61.31 56.84 <1.0 56.84
5 57.54 <1.0 60.56 56.14 <1.0 56.14
6 57.54 <1.0 60.56 56.84 <1.0 56.84
7 58.25 <1.0 61.31 56.84 <1.0 56.84
8 58.95 <1.0 62.05 57.54 <1.0 57.54
Average 58.07 <1.0 61.12 56.92 <1.0 56.92
Efficienc y
107.37 % (OEC/TEC) Base capacity ratio of OEC/TEC:
56.92 considered as 100 %
Rinse 1.5 BV 2.0 BV
The strong acid cation exchange resin was evaluated for performance study for water
de-mineralization application.
5 A synthetic feed solution for water demineralization application was prepared as
follows.
A synthetic feed solution of 1000L was prepared by dissolving accurately weighed
10 quantities of 132.3 g of calcium chloride dihydrate, 182.7 g of magnesium chloride
hexahydrate, 23.4 g of sodium chloride and 168.0 g of sodium bicarbonate. Each salt
was dissolved and diluted to about 10L in a polyethylene container. All these salt
solutions were further gently added to synthetic feed water tank and diluted to 1000L
with deionized water. The synthetic feed water quality parameters are tabulated in Table
15 10.
Table 10: The synthetic feed water quality parameters for demineralization application
Parameter Concentration
Total Hardness 180 ppm as CaCO3
Calcium hardness 90 ppm as CaCO3
Magnesium hardness 90 ppm as CaCO3
Sodium 120 ppm as CaCO3
Alkalinity 100 ppm as CaCO3
Total Cations 300 ppm as CaCO3
58
Na/Total Cation, % 40.0
Alkalinity/Total Cation, % 33.3
A total of six demineralization cycles study was conducted using 5% HCl solution as a
regenerant after each cycle. Each cycle was conducted till the resin treated water sodium
content was less than 1 ppm as Sodium (Na). Average operating exchange capacity was
noted for each resin after completing 6 cycles and OEC / TEC ratio was calculated. These
5 results are tabulated in Table 11 and Table 12.
Table 11: Comparative study with Regeneration level of 50g (100% HCl) / L of resin
Example No
TEC as
CaCO3, g
/L
OEC as
CaCO3, g/L
% OEC /
TEC
% Whole bead
count
27 90 49.85 55.39 98
29 78 41.22 52.84 95
30 84 44.46 52.93 95
31 86 46.24 53.77 95
35 90 49.58 55.09 95
36 91 45.16 49.63 95
37 78 46.25 59.29 70
38 85 47.17 55.49 80
39 86 47.41 55.13 95
40 92.5 48.56 52.50 95
41 78 47.41 60.78 95
42 82 45.13 55.04 85
43 80 42.73 53.40 85
44 86 47.73 55.50 80
45 86 46.33 53.87 70
46 90 48.20 53.56 90
Indion 225 H 94 50.30 53.51 >90
59
Table: 12 Comparative study with Regeneration level of 40 g (100% HCl) / L of resin
Resin from Example
No.
Total exchange
capacity (TEC) as
CaCO3, g /L
Operating exchange
capacity (OEC) as
CaCO3, g/L
% OEC / TEC
37 78 41.69 53.43
41 78 39.78 51.00
44 86 42.12 48.97
45 86 40.21 46.75
Indion 225 H 94 42.12 44.80
5
Example 57
10 Performance evaluation of strong base anion exchange resin
The strong base anion exchange resin product obtained in the Example 52 was evaluated
for performance in demineralized water applications. The procedure followed was as per
ASTM Designation: D 2187–94. The performance of the resin made in this invention,
15 was compared with performance of commercial resin Indion GS300 in chloride (Cl)
form resin for water demineralization applications. The experimental set up is depicted
in the Figure 2.
20 A synthetic feed solution for water demineralization application was prepared as
follows.
A synthetic feed solution of 1000L was prepared by dissolving accurately weighed
25 quantities of 87.5 g of sodium chloride, 35.5 g of sodium sulphate, 49.5 g of sodium
60
metasilicate (100 % pure basis) and 10.1 g of sodium bicarbonate. Each salt was
dissolved and diluted to about 10L in a polyethylene container. All these salt solutions
were further gently added to synthetic feed water tank and diluted to 1000L with
deionized water. The synthetic feed water quality parameters are tabulated in Table 13.
5 This feed water first passed through the column of SAC (Cation) resin in H+ form to get
the following water quality after ex-cation. This water to be checked for Na content for
every 30 minutes during passing through the cation resin column as mentioned in above
10 Experiment 55.
Table 13: The synthetic feed water quality parameters for demineralization application
15
Parameter Concentration
EMA 100 ppm as CaCO3
Chlorides 75 ppm as CaCO3
Sulphates 25 ppm as CaCO3
SiO2 27 ppm as CaCO3
Total alkalinity + SiO2 Total Anions 133 ppm as CaCO3
Methyl orange alkalinity 6 ppm as CaCO3
% SiO2/Total alkalinity 20.3
% SO4/EMA 25
Two glass columns were filled with 250 mL each resin from Example 52 and another
one column with 250 mL of commercial resin comprising single component cross-linked
20 copolymer in chloride form.
The feed solution prepared above was passed through the columns at a flow rate of 24
BV/ hour in gravity flow mode. Water exiting column outlet was intermittently checked
25 for silica content at every 30 minutes. The SiO2 content analysis was conducted by
61
HACH spectrophotometer DR2010 according to instrument specified Programme No
651.
5 The column operation was stopped when the concentration of silica (SiO2) in column
out let reached to 0.2 ppm. Total feed solution passed through the column was noted and
OEC of the resin was calculated. First cycle was called conditioning cycle. Thereafter
the resin was regenerated by passing 4 % w/v sodium hydroxide solution through resin
bed in co-current mode with 30 minutes contact time. The resin was then rinsed with
10 deionized water to remove residual alkali from the resin bed. Three demineralization
cycles were similarly conducted. The performance of the resin was evaluated at
regeneration level of 60 g/L of 100 % NaOH/L of resin (using 4% w/v NaOHsolution).
The results are tabulated in Table 14.
15
Table 14: SBA resin - Comparative results at 60g/L regeneration level average of three
cycles
Parameters Example 52 resin in
Cl form
Indion
GS300
Cl form
TEC, g/L as CaCO3. 51.0 65.0
OEC, g/L as CaCO3. 28.31 26
OEC / TEC, % 55.5 40.0
Silica Leakage ppb as SiO2. 21 30
Rinse water volume BV for slow rinse (pH < 9.5) 1.5 2.0
Remarks Higher Regeneration efficiency at
lower TEC level.
62
Example 58
5 The weak acid cation exchange (WAC) resin product obtained in the Examples 53 and
54 were evaluated for their performance for de-alkalization of water application. The
procedure followed was as per ASTM.Designation: D 2187–94 (Reapproved 2004). The
columns used for the experiment is shown in the Figure 2.
10
A synthetic feed solution of 1000L was prepared by dissolving accurately weighed
quantities of 185.0g of calcium hydroxide (about 80% pure) in 200L of deionizedwater
dissolved it by purging CO2 gas in water. The CO2 gas to be purged till entire calcium
hydroxide is dissolved in 200L water. This water is further diluted to 1000L in feed water
15 tank using deionized water to get the following water quality. The feed water quality is
tabulated in Table 15.
Table 15: The synthetic feed water quality parameters for demineralization application
20
Parameter Concentration
M. Alkalinity 200 ppm as CaCO3
Total Hardness 200 ppm as CaCO3
Calcium hardness 200 ppm as CaCO3
Total Cations 200 ppm as CaCO3
Three glass columns were filled with 250 mL of each of weak acid cation resin
(Examples 53 and Example 54) and another third column with 250 mL of commercial
25 resin (Indion 236) comprising single component cross-linked copolymer.
63
The feed solution prepared above was passed through the columns at a flow rate of
20BV/ hour in gravity flow mode. The treated water exiting from column outlet was
tested for alkalinity content at 30 minutes intervals. The alkalinity test was based on
acid-base titration using phenolphthalein and methyl orange as indicators.
5
The experiment was stopped, when the concentration of methyl orange alkalinity in
column outlet as CaCO3 reached to 5.0 ppm. Total feed solution passed through the
column was noted and operating exchange capacity of the weak acid cation exchange
10 resin was calculated as the below formula
(Feed alkalinity as CaCO3) x (Total output in
Liter) OEC =
Resin volume in Liter x 1000
15
First cycle was called conditioning run. After this conditioning run, the resin was
regenerated by passing 5% w/v HCl solution through resin bed in co-current mode. The
contact time was 45 minutes. The resin was then rinsed with deionized water to remove
residual acid from resin bed. Three further cycles of de-alkalization were similarly
20 conducted.
The performance of the resin was evaluated at regeneration level of 115 % of work done
(considering about 85% regeneration efficiency of WAC resin with HCl against the work
25 done) by the resin using 5% w/v HCl solution. The results are tabulated in Table 16.
Table 16: WAC resin application in water de-alkalization application
Parameter Example 53 Example 54 Indion 236 H
TEC, g /L as CaCO3. 138.0 97.5 210.0
64
OEC, g/L as CaCO3. 68.34 58.13 102.26
OEC/TEC, % 49.52 59.62 48.69
Average leakage ofmethyl
orange alkalinity, ppm as
CaCO3.
< 1.0 < 1.0 < 1.0
Rinse water volume BV for slow
rinse ( pH > 4.5)
1.5 1.5 2
Remarks Higher Regeneration efficiency at lower TEC
level.
5
Example 59 X-ray Microtomography Imaging
X-ray microtomography imaging of two component crosslinked polymer beads and the
ion exchange resins synthesized there from was carried out as per the details given
10 below.
Instrument Details:
Model & Make: X radia Versa 510, Carl Zeiss, USA.
15 X-ray Source: 160 kV high energy micro-focus sealed X-ray tube.
Detector: 2k x 2k high resolution 16-bit CCD digital camera assembly with in-line
optical magnifiers
Parameters & Methodology:
20
X-ray Power (kV/W): 60/5, Objective: 4 X, Field of View (FOV): 3.1 mm, Exposure
Time: 1 sec, Filter: Nil, Cone angle: 7.48 Deg, Voxel Size: 3.1 microns, Projections:
3201, Scan Time: 3 hours 16 mins
IV. Software’s for Imaging and Processing:
25
Image Acquisition: Scout-and-Scan Control System, Version 11.1.8043.19515 (Carl
Zeiss, USA)
65
Image Processing: Dragonfly Pro, Version 3.6.1.492 (Object Research Systems Inc,
Canada).
Imaging Protocol:
5 Samples were loaded on to micro-pipette tips, sealed and placed on a sample holder.
Sample holder is kept in between X-ray source and detector. Imaging parameters were
optimized to attain X-ray projections of the sample with significant contrast using Scoutand-Scan Control System software.
Optimized imaging parameters were given above and kept constant for all fivesamples.
10 X-ray energy of 60 kV was used during the imaging process. 3201 X-ray projection
images were captured per sample with 1 sec X-ray exposure per projection. Objective
lens with 4X magnification was employed to attain a pixel size of 3.1 microns. 2D virtual
cross-sections of sample were generated from the X-ray projections, based on a
reconstruction algorithm1. Time required for imaging process was approximately 3
15 hours per sample, followed by 1 hour post-processing of images using Dragonfly Pro
software package. Normalization of the attenuation histogram, filtration of images and
diameter measurement were performed during the post-processing stage
The images presented in Figure 3 illustrate that the two component crosslinked polymer
beads of Example 1 and the strong acid cation exchange resin of Example 40, strong
20 base anion exchange resin of Example 52 and weak acid cation exchange resin of
Example 53 exhibit uniform absorption contrast indicating lack of core shell morphology
whereas the strong acid cation exchange resin of Example 27, exhibits lowerabsorption
contrast in its core indicating presence of core shell morphology.
66
CLAIMS:
WE CLAIM:
5 1. A two component cross-linked copolymer composition in bead form comprising
the cross-linked copolymer of the first component formed in the first step having
lower cross-linker content than the cross-linker content in the cross-linked
copolymer of the second component incorporated in the second step, wherein the
said composition exhibits a single stage swelling behaviour in solvent.
10
2. A two component cross-linked copolymer composition in bead form as claimed in
claim1 wherein the said composition exhibits a single stage swelling behaviour in
the solvent which is toluene.
15
3. A two component cross-linked copolymer composition in bead form as claimed in
claim 2 wherein the maximum swelling is reached in 0.75 to 24 hrs.
20
4. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the weight ratio of the cross linked copolymer of the first
component to that of the cross linked copolymer of the second component is in the
range 1:1.2 to 1:2.64.
25
5. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the monovinyl monomer of the cross-linked copolymer of the first
component is selected from styrene, methyl methacrylate, methyl acrylate and
30 methacrylic acid.
67
6. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the monovinyl monomer of the cross-linked copolymer of the
second component is selected from styrene, methyl methacrylate, methyl acrylate,
methacrylic acid, hydroxy propyl acrylate and hydroxy ethyl methacrylate.
5
7. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the cross-linker content of the cross-linked copolymer of the first
component is in the range of 1.8 to 3 % w/w.
10
8. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the cross-linker content of the cross-linked copolymer of the
second component is in the range of 2 to 9 % w/w.
15
9. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the cross-linker in the cross-linked copolymer of the first
component is selected from divinyl benzene (DVB), ethylene glycol
20 dimethacrylate (EGDMA), 1, 7-octadiene, trivinyl cyclohexane (TVCH) .
10. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the cross-linker in the cross-linked copolymer of the second
25 component is selected from divinyl benzene (DVB), ethylene glycol
dimethacrylate (EGDMA), 1, 7-octadiene, trivinyl cyclohexane (TVCH) .
68
11. A two component cross-linked copolymer composition in bead form as claimed in
claim 1 wherein the bead size is in the range of 250 to 800 µm.
5 12. A process for the synthesis of two component cross-linked copolymer composition
in bead form as claimed in claim 1 comprising the steps of adding to the reactor a
weighed amount of water, a protective colloid and a stabilizer, raising the
temperature to about 750C while stirring in the range of 200 and 300 rpm, adjusting
the stirring in the range of 60 and 70 rpm, adding the monomer composition
10 constituting the cross-linked copolymer of the of the first component, maintaining
the temperature at 750C , maintaining the stirring speed between 100 and 120 rpm
when the reaction mass becomes sticky, continuing the polymerization for about 3
hours, raising the temperature to 850C and continuing polymerization for about 3
hours, then raising the temperature to 95 0C and continuing polymerization for
15 about 3 hours, cooling the reaction mass to room temperature, separating out the
aqueous medium, adding to the cross-linked copolymer of the of the first
component formed, the monomer composition constituting the cross-linked
copolymer of the of the second component, imbibing the cross-linked copolymer
of the first component formed with the monomer composition constituting the
20 cross-linked copolymer of the second component, over a period of about 2 hours,
adding fresh aqueous solution containing the protective colloid and the stabilizer,
stirring the reaction mass between 100 and 120 rpm, continuing the polymerization
at 75 0C, for about 3 hours, raising the temperature to 85 0C continuing
polymerization for about 3 hours, raising the temperature to 950C continuing
25 polymerization for about 3 hours, cooling the reaction mass to room temperature,
69
washing the two component cross-linked copolymer beads with water until the
wash water showed no foaming, and drying the recovered beads in a hot air oven
at 100 0C for 8 hours.
5 13. A process as claimed in claim 12 wherein the protective colloid is selected from
hydroxy propyl methyl cellulose , hydroxy propyl ethyl cellulose, and PVA.
14. A process as claimed in claim 12 wherein the concentration of protective colloid
10 in water is between 0.08 to 0.4 % w/w.
15. A process as claimed in claim 12 wherein the stabilizer is selected from
monosodium phosphate, di sodium phosphate and tri sodium phosphate.
15
16. A process as claimed in claim 12 wherein the stabilizer concentration in water is
about 0.5 to 0.82 % w/w.
20
17. A process as claimed in claim 12 wherein the monomer constituting the crosslinked copolymer of the first component is selected from styrene, methyl
methacrylate, methyl acrylate and methacrylic acid.
25
18. A process as claimed in claim 12 wherein the monomer constituting the crosslinked copolymer of the second component is selected from styrene, methyl
methacrylate, methyl acrylate, methacrylic acid and hydroxy ethyl methacrylate.
70
19. A process as claimed in claim 12 wherein the cross-linker constituting the crosslinked copolymer of the first component is selected from divinyl benzene (DVB),
ethylene glycol dimethacrylate (EGDMA), 1,7-octadiene and trivinyl cyclohexane
(TVCH).
5
20. A process as claimed in claim 12 wherein the cross-linker constituting the crosslinked copolymer of the second component is selected from divinyl benzene
(DVB), ethylene glycol dimethacrylate (EGDMA), 1,7-octadiene and trivinyl
10 cyclohexane (TVCH).
21. A process as claimed in claim 12 wherein the cross-linker content of the crosslinked copolymer of the first component is in the range of 1.8 to 3 % w/w.
15
22. A process as claimed in claim 12 wherein the cross-linker content of the crosslinked copolymer of the second component is in the range of 2 to 9 % w/w.
20
23. An ion exchange resin in bead form comprising a two component cross-linked
copolymer composition as claimed in claim 1 wherein the said ion exchange resin
exhibits a ratio of operating exchange capacity (OEC) to total exchange capacity
(TEC) in the range of 49 to 61%.
25
24. An ion exchange resin as claimed in claim 23 wherein the said ion exchange resin
is a strong acid cation exchange resin.
71
25. A strong acid cation exchange resin, as claimed in claim 24 wherein the said strong
acid cation exchange resin has a total exchange capacity in the wet form in the
range of 1.25 to 1.85 eq/L
5
26. A strong acid cation exchange resin, as claimed in claim 24 wherein the said strong
acid cation exchange resin has an OEC/TEC ratio in the range of 49% to 61% at
50 g/L regeneration level.
10
27. A strong acid cation exchange resin as claimed in claim 24 wherein the said strong
acid cation exchange resin has a crushing strength in the range of 500 g to 1000 g
/ bead.
15
28. A strong acid cation exchange resin, as claimed in claim 24 wherein the said strong
acid cation exchange resin when subjected to osmotic shock resistance test retains
a whole bead count greater than 85%.
20
29. A process for the synthesis of a strong acid cation exchange resin, as claimed in
claim 24 comprising the steps of charging the two component cross-linked
copolymer composition as claimed in claim 1 to the reactor, adding concentrated
25 sulfuric acid to the reactor, stirring the contents of the reactor at 200 rpm, heating
the reaction mass to 110 ± 2 0C and continuing the reaction for the desired timeby
observing the progress of reaction under microscope, cooling the reaction mass,
draining off the sulfuric acid, subjecting the reaction product to programmed
hydration using sulfuric acid aliquots of decreasing sulfuric acid concentration,
72
washing the reaction product with deionised water till the washings are free from
acid and recovering the product by decanting off excess water.
5 30. A process for the synthesis of a strong acid cation exchange resin as claimed in
claim 29 wherein the ratio of two component cross-linked copolymer composition
to sulfuric acid is in the range of 1:3.6 to 1:10.8 w/w.
10 31. A process for the synthesis of a strong acid cation exchange resin as claimed in
claim 29 wherein the concentration of sulfuric acid is 93 -100 % w/w.
32. A process for the synthesis of a strong acid cation exchange resin as claimed in
15 claim 29 wherein the reaction time is 2 to 6 hours.
33. A process for the synthesis of a strong acid cation exchange resin as claimed in
claim 29 wherein programmed hydration using sulfuric acid involves stirring the
20 reaction product for 30 to 45 minutes, with 250 mL aliquots of sulfuric acid
solution in water of sulfuric acid concentration 85%, 78%, 65%, 45%, 30%, 25%
and 15% w/w.
25 34. An ion exchange resin as claimed in claim 23 wherein the said ion exchange resin
is a strong base anion exchange resin.
73
35. A strong base anion exchange resin, as claimed in claim 34 wherein the said strong
base anion exchange resin has a total exchange capacity in the wet form is in the
range of 0.74 and 1.02 eq/L
36. A strong base anion exchange resin, as claimed in claim 34 wherein the said strong
5 base anion exchange resin has OEC/TEC ratio in the range of 55 to 57 %
37. A strong base anion exchange resin, as claimed in claim 34 wherein the said strong
base anion exchange resin has a crushing strength in the range of 300 g to 600 g /
10 bead.
38. A strong base anion exchange resin, as claimed in claim 34 wherein the said strong
base anion exchange resin when subjected to osmotic shock resistance test retain a
15 whole bead count greater than 85 %.
39. A process for the synthesis of a strong base anion exchange resin as claimed in
claim 34 comprising the steps of charging into the reactor methanol-formaldehyde
20 solution, methanol, methylal, water and ferric chloride, adding chlorosulfonic acid
over a period of 5 - 6 hours maintaining the reaction temperature at 38 – 40 0C,
charging the two component cross-linked copolymer composition as claimed in
claim 1 into the reactor, at around 20 0C continuing the reaction at 38 – 40 0C for 5
- 6 hours, cooling the reaction mass below 20 0C, quenching the reaction by
25 washing the reaction mass with three aliquots of 300 mL methanol, washing with
dilute aqueous sodium hydroxide solution and then water till the pH of washings is
neutral, charging the chloromethylated resin to the reactor containing water,
74
draining out water and swelling the resin with methylal, leaving excess methylal in
the reactor, adjusting the pH to 10 - 12 by adding aqueous sodium hydroxide,
adding 30% aqueous trimethyl amine over a period of 30 - 45 minutes, stirring at
25 – 30 0C for 30 minutes, raising the temperature to 42 – 45 0C, maintaining for 6
hours, recovering methylal by heating up to 80 0
5 C, cooling the reaction mass to
room temperature and adding 50 mL of 7% hydrochloric acid, stirring for half an
hour, filtering the reaction mass and washing with demineralized water till the
washings free from acid and recovering the product by filtration.
10
40. A process for the synthesis of a strong base anion exchange resin, as claimed in
claim 39 wherein the ratio of two component cross-linked copolymer composition
to chloromethylating agent is in the range of 0.94 to 2.25 w/w.
15
41. An ion exchange resin as claimed in claim 23 wherein the said ion exchange resin
is a weak acid cation exchange resin.
20 42. A weak acid cation exchange resin as claimed in claim 41, has a total exchange
capacity of 1.95 to 2.76 eq/L.
43. A process for the synthesis of weak acid cation exchange resin as claimed in claim
25
41 comprising charging into reactor water, adding protective colloid followed by
sodium chloride, stirring the mixture at 200-300 rpm, adjusting the stirrer speedto
60-70 rpm, charging into the reactor the monomer composition constituting the
cross-linked copolymer of the first component, raising the temperature to 65
0
30 C,
75
increasing the stirring speed to 100-120 rpm after 40-45 minutes, continuing the
polymerization at 65 0C for three hours, followed by continuing polymerization at
75 0C for three hours, followed by continuing polymerization at 850C for three
hours, and finally at 950C for three hours, washing the reaction product with
5 deionized water till the washings are free from surfactant as evidenced by absence
of foaming in the washings and drying the product at 100 0C for 8 hours,imbibing
the cross-linked copolymer of the of the first component, with the monomer
composition constituting the cross-linked copolymer of the of the second
component for about two hours, charging the aqueous phase containing the
10 protective colloid and sodium chloride into the reactor, stirring the reaction mass
at 100-120 rpm, and polymerizing the reaction mass at 65 0C for three hours,
followed by continuing polymerization at 75 0C for three hours, followed by
continuing polymerization at 85 0C for two hours, adding caustic lye to thereactor
and continuing heating at 85 0C for three hours and finally at 95 0C for three
15 hours, cooling the reaction mass to room temperature and washing with
demineralized water.
44. A process for the synthesis of weak acid cation exchange resin as claimed in claim
20 43 wherein the protective colloid is selected from hydroxy ethyl cellulose, carboxy
methylcellulose, and sodium lignosulfonate.
45. A process for the synthesis of weak acid cation exchange resin as claimed in claim
25 43 wherein the composition constituting the cross-linked copolymer of the first
76
component comprises monomers selected from methyl acrylate and methacrylic
acid.
5 46. A process for the synthesis of weak acid cation exchange resin as claimed in claim
43 wherein the composition constituting the cross-linked copolymer of the second
component comprises monomers selected from methyl methacrylate, methyl
acrylate and methacrylic acid and hydroxy ethyl methacrylate.
10
47. A process for the synthesis of weak acid cation exchange resin as claimed in claim
43 wherein the composition constituting the cross-linked copolymer of the first
component comprises cross-linkers selected from divinyl benzene (DVB), ethylene
glycol dimethacrylate (EGDMA), 1,7-octadiene, trivinyl cyclohexane (TVCH).
15
48. A process for the synthesis of weak acid cation exchange resin as claimed in claim
43 wherein the composition constituting the cross-linked copolymer of the of the
second component comprises cross-linkers selected from divinyl benzene (DVB),
20 ethylene glycol dimethacrylate (EGDMA), 1,7-octadiene, trivinyl cyclohexane
(TVCH).