DESC:FIELD OF THE INVENTION:

The present invention relates to a process for preparation of high crush strength high exchange capacity Resin acid catalyst. Moreover, this resin acid catalyst finds application in processes like C4- dimerization process, etherification of light olefin, aldehyde removal during the mono-ethylene glycol (MEG) manufacturing.

BACKGROUND OF THE INVENTION:

US2500149 describes use of swelling the crosslinked poly(styrene-co-divinyl) benzene in organic liquid and then treating the swollen granular material with a sulphonating agent by heating the mixture at a reaction temperature. Swelling reduces cracking, spalling, or shattering when subjected to internal strain or to large external stresses or blows. However, the examples cited is for gel type resin where no pore forming agent is used.

U.S. Patent No 4209592 describes manufacture of high-capacity cation exchange resin having greater than 95% unbroken beads by doing sulfonation in using liquid sulphur trioxide dissolved in chlorinated hydrocarbon solvent. Sulfonated resin thus obtained has ion exchange capacity of around 4.4 eq/Kg.

US Patent 3158583 describes process for sulfonating cross-linked polymers styrene and divinylbenzene with a sulphonating agent like oleum containing from about 10 to 70% by weight of free SO3, to obtain a final sulphonated product containing 1.5 to 2 sulphonic acid groups per aromatic nucleus.

EP 1421045 describes method for dimerizing isobutene, wherein, the isobutene is brought into contact with a porous cation exchange resin. The macroporous resin comprises of styrene polymer cross-linked with divinyl benzene, and sulphonic acid groups adhering to the polymer having acid capacity of which is 4.7 equivalents/kg at a minimum, and the portion of divinyl benzene units of which is 5% by weight at a minimum and 14% by weight at a maximum.

CN 200310123894 patent describes preparation of macroporous resin using porogen like C8-C20 linear paraffin. The obtained resin was sulfonated using 98~106% sulphuric acid.

Conventionally macroporous resins are prepared through a polymerization process wherein suitable monomers like styrene, divinylbenzne are polymerized by suspension techniques in the presence of compounds arbitrarily referred to as “porogen." The “porogen” are defined as compounds that form homogeneous solutions with the monomer mixture, but do not take part in polymerization and do not act as either solvents or as swelling agents for the copolymers. These compounds are generally organic liquids. It is believed that the porogen enters into pores of the macroporous resins and does not allow polymerization in the pores. Moreover, copolymers formed is insoluble in the porogen. Sulphonated resin acid catalysts are available in the market for application in many different fields. The commercial catalyst presently being used lacks such high crush strength and ion exchange capacity. High crush strength of the catalyst helps to maintain the spherical nature of the catalyst and its acidity during any physical or chemical pressures generated during its application.

SUMMARY OF THE PRESENT INVENTION:

The present invention discloses a process for preparation of high crush strength, high exchange capacity Resin acid catalyst. In one of the aspects the present invention, a two-step process for preparation of high crush strength high exchange capacity Resin acid catalyst, said process comprising the steps:
a. preparation of base resin:
i. heating a solution of water, suspending agent and sodium chloride till complete dissolution, to obtain an aqueous phase;
ii. mixing styrene and divinylbenzene (DVB), followed by addition of initiator benzoyl peroxide (BPO), and porogen to form an organic phase;
iii. mixing the aqueous phase and the organic phase, to initiate polymerization and obtaining reaction product;
iv. washing the reaction product with hot water, and removing the residual porogen by vacuum distillation;
v. drying copolymer beads under vacuum and sieving to obtain base resin;
b. Sulfonation of base resin:
i. suspending base resin in dichloroethane;
ii. treating swelled base resin with mixture of sulphuric acid and 20% oleum;
iii. washing sulfonated resin with water to neutralise pH, and vacuum drying to obtain resin acid catalyst.

In another aspect of the present invention, the resin acid catalyst is sulphonated copolymer of styrene and divinylbenzene.
In another aspect of the present invention, the solution in step (a) (i) is heated at temperature range of 60?C to 90?C, for 2-3 hours, wherein the mixture of aqueous phase and organic phase of step (a) (ii) is polymerised at temperature of 30 to 150?C, and stirred at 450 rpm; wherein the copolymer bead of step (a) (v) is vacuum dried in an oven at 80°C for at least 24 hour and sieved for 425 microns to 1200 microns cut.
In another aspect of the present invention, mixture of aqueous phase and organic phase of step (a) (ii) is polymerised at 72°C for 1 hour, then at 80°C for 10 h and then at 88°C for 4 hours at a stirring speed of 450 rpm.
In another aspect of the present invention, the swelled base resin of step (b) (ii) is treated with sulphuric acid and 20% oleum; wherein the sulfonated resin of step (b) (iii) is vacuum dried at 50°C for 8-10 hours to obtain resin acid catalyst.
In another aspect of the present invention, the swelled base resin of step (b) (ii) is treated with sulphuric acid and 20% oleum (50:50) at 180 rpm for 4 hours.
In another aspects the present invention provides a two-step process for preparation of high crush strength high exchange capacity Resin acid catalyst comprises:
a. preparation of base resin
i. water, suspending agent and sodium chloride as aqueous phase, heated at 65 °C for 2-3 hours;
ii. styrene and divinylbenzene (DVB) mixed, followed by addition of initiator benzoyl peroxide (BPO), and porogen as organic phase,
iii. aqueous phase and organic phase are mixed, and polymerised at a 72°C for 1 hour, 80°C for 10 h and 88°C for 4 hours at a stirring speed of 450 rpm,
iv. reaction product washed with hot water, and residual porogen removed by vacuum distillation
v. copolymer beads dried under vacuum in an oven at 80°C for at least 24 hour and sieved for 425 microns to 1200 microns cut.
b. Sulfonation of base resin
i. base resin is suspended in dichloroethane,
ii. swelled base resin treated with mixture of sulphuric acid and 20% oleum (50:50) at 180 rpm for 4 hours,
iii. sulfonated resin washed with water to neutralise pH, and vacuum dried at 50°C for 8-10 hours to obtain resin acid catalyst.
In another aspects of the present invention, the divinylbenzene is in the range of 20 – 25 wt% of styrene.
In one of the aspect of the present invention the molar concentration of free radical initiator is in the range of 0.01 to 5.0 % of the total weight of monomers.

In another aspect of the present invention, the free radical initiator is selected from group of peroxides, proxy-compounds, azo compounds, or mixture thereof; preferably the free radical initiator is benzoyl peroxide (BPO).

In another aspect of the present invention, the porogen or pore forming agent is selected from group of aromatic compounds, halogenated solvents, plasticisers, polymers, or mixture thereof.

In another preferred aspect of the present invention, the porogen or pore forming agent is selected from group of aromatic compounds, halogenated solvents, plasticisers, polymers, or mixture thereof, and volume fraction of porogen or pore forming agent is about 35%.
In yet another aspect of the present invention, the suspending agents is selected from polyvinylalcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, poly (vinyl pyrrolidine), polyacrylate salts, polymethyacrylate salts, dimethyldialkylammonium polymers, nitrite and dichromatic salts, calcium phosphate salts, carbonate salts, sulfate salts, bentonite clays, gum arabic, lignosulfonates, gelatine, xanthan gums and mixture thereof, and wherein the suspending agents is in range of 0.01 to 0.5 % of total weight of the monomers.

In yet another aspect of the present invention, the base resin is suspended in the swelling agent for about 1 to 8 hours.

In another preferred aspect of the present invention, the conversion of base resin to resin acid catalyst is greater than 95 %.

In another preferred aspect of the present invention, the resin acid catalyst is in range of 300 to 1500 micron, with 90% particles having particle size in range of 425 to 1200-micron, surface area in range of 10 to 100 m2/g, pore size in range of 200 to 300 Å, pore volume in range of 0.2 to 0.8 cm3/g.

In another aspect of the present invention the resin acid catalyst is having crush strength of atleast 150 N/mm, and ion exchange capacities in range of 4.9 to 5.5 eq/kg, preferably > 5.2 eq/kg.

OBJECTIVES OF THE PRESENT INVENTION:

It is a primary objective of the invention to provides a process for preparation of high crush strength, high exchange capacity Resin acid catalyst.

It is the further objective of the present invention to provide a synthetic resin articles having high crush strength, high exchange resin capacity and having a macro-porous structure.

Further objective of the invention is to provide a catalyst having high crush strength and high ion exchange capacity which is due to the process developed for sulphonation of the copolymer.

DESCRIPTION OF THE INVENTION:

The present invention provides a process for preparation of high crush strength high exchange capacity resin acid catalyst.
The main embodiment of the present invention provides a process for preparation of high crush strength high exchange capacity resin acid catalyst comprising of
i. copolymerization of styrene and divinylbenzene to prepare a base resin wherein, the copolymers are spherical shaped or beads having bigger pore volume,
ii. sulphonation of the resin catalyst using mixture of oleum and sulphuric acid resulting in formation of resin acid catalyst
In another aspect of the present invention, the base resin is prepared by the copolymerization of styrene and divinylbenzene using suspension polymerization technique. The process of suspension polymerization, in general, takes place in two phases, where one phase is organic phase (monomer phase), and the second phase is aqueous phase. In an embodiment, the organic phase consists of styrene, divinylbenzene, porogen and an initiator. In another embodiment, the aqueous phase consists of water, suspending agent and sodium chloride. For the monomer phase, monomers i.e., styrene and divinylbenzene which belong to class of compounds also known as monoethylenically unsaturated monomers and polyvinylidene monomers, respectively. The polyvinylidene monomers used are in the range of 20 – 25 wt% of the monoethylenically unsaturated monomers.

The initiator used is free radical initiator including peroxides such as benzoyl peroxide, tert-butyl hydroperoxide, cumene peroxide, tetralin peroxide, acetyl peroxide, caproyl peroxide, tert-butyl perbenzoate, tert-butyl diperphthalate, methyl ethyl ketone peroxide, etc., proxy-compounds such as potassium persulfate, sodium perborate and ammonium persulfate and azo compounds such as azo-bisisobutyronitrile, 2,2-azobis-(2-methyl-butyronitrile), 2-t-butylazo 2-cyano propane and mixture thereof. Suitable concentrations are from 0.01 to 5.0% of the total weight of monomers.
The porogen or pore forming agent is selected from aromatic compounds such as toluene and benzene, alcohols such as butanol, iso-octanol, cyclohexanol, dodecanol, and isoamyl alcohol, esters such as ethyl acetate and butyl acetate, saturated hydrocarbons such as n-heptane, iso-octane, halogenated solvents such as dichloroethane and trichloroethylene, plasticisers such as dioctylphthalate and dibutyl adipate, and polymers such as poly(vinyl methyl ether), poly(ethylene oxide), poly(vinyl acetate), poly(methyl methacrylates), poly(vinyl acetate co-maleic or fumric acid and esters), fatty alcohol ethoxylates, fatty alcohol alkoxylates, alcohol alkoxylates, fatty acid athoxylates, castor oil ethoxylates, fatty amine ethoxylates, alkylphenol ethoxylates, alkyl ethoxy carboxylic acids, and combinations thereof. The preferred porogen is n-heptane and toluene and mixture thereof. Volume fraction of porogen in the total organic phase is around 35%.

The aqueous phase consists of water, suspending agent and sodium chloride. Sodium chloride or “the salt” may be added to the aqueous phase in order to decrease the solubility of the monomers in water. Suitable concentrations of salt are 10 to 50 grams per 100 grams of water.

The suspending agents are selected from polyvinylalcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, poly (vinyl pyrrolidine), polyacrylate salts, polymethyacrylate salts, dimethyldialkylammonium polymers, nitrite and dichromatic salts, calcium phosphate salts, carbonate salts, sulfate salts, bentonite clays, gum arabic, lignosulfonates, gelatine and xanthan gums and combinations thereof. Suitable amounts ranging from 0.01 to 0.5% by the total weight of the monomers.

In an embodiment, the process of suspension polymerization is carried out by preparing the aqueous phase by gentle stirring under heating under inert atmosphere followed by mixing the components of organic phase and heating the mixture at from 70?C to 90?C for 5 hr. The polymerization is preferably carried out at temperatures from 30 to 150?C. After removal of the aqueous phase, organic phase is washed with water and finally n-heptane is distilled off.

In an embodiment, the copolymer i.e., the base resin catalyst is opaque white spherical beads having particle size of about 300 to 1500 micron, surface area of about 10 to 100 m2/g, pore size of about 150 to 350 Å and pore volume of 0.1 to 0.5 cm3/g.

In an embodiment, the resin acid catalyst is prepared by sulphonation of the base resin using mixture of oleum and sulphuric acid and swelling agent. In an embodiment, the swelling agent is selected from benzene, toluene, xylene, ethylbenzene, isopropyl benzene, chlorobenzene, tetrachloroethane, tetrachloroethylene, dichloroethane, dichloropropane, nitrobenzene, nitromethane and polyfluorinated benzene compound. The preferred swelling agent is dichloroethane.

In an embodiment, the base resin is suspended in the preferred swelling agent for about 1 h to 8 h at temperatures below the boiling point of the selected swelling agent.

In another embodiment, the base resin is suspended in the preferred swelling agent for about 1 hour to 8 hours at temperature range of 25°C to 80°C.

The sulphonation is carried out using sulphuric acid and oleum. The treatment of the base resin with sulphuric acid and oleum greatly affects the crush strength of the resin acid catalyst.

In an embodiment, the swelled base resin is treated with sulphuric acid in weight ratio of about 1 to 10 at a temperature of 25° C to 40° C for a period of 20 minutes to 2 hours. During this process, the swelling agent is distilled off and can be recycled. In an embodiment, oleum is added to the reaction in weight ratio of about 1 to 8 at a temperature of 100° C to 140° C for a period of 1 hour to 5 hours.

The sulphonation process of the base resin is terminated after appropriate time by quenching and hydration with the methods known in the art, for example, by slow addition of water or slow addition of diluted solution of sulfuric acid or both to neutralize the acidity.

In an embodiment, the percentage conversion of base resin to resin acid catalyst is greater than 95. In another embodiment, the resin acid has particle size of about 300 to 1500 micron with greater than 90% particles having particle size of 425 to 1200 micron, surface area of about 10 to 100 m2/g, pore size of about 200 to 300 Å, pore volume of 0.2 to 0.8 cm3/g. In another embodiment, the resin acid catalyst has crush strength of 120 to 200 N/mm, maximum axial force at break of about 1500 to 2500, stiffness of about 250 to 350 N/mm and have thermal stability up to 250?C.

In an embodiment, the resin acid catalyst has ion exchange capacities of about 4.9 to 5.5 eq/kg.
EXAMPLES

The following examples are included herein for illustrative purposes only. Those skilled in the art will appreciate that many modifications may be made in the invention without changing the essence of invention.

Test Methods:

Concentration of active sites (Dry weight acid capacity): ASTM D2187

This test method covers the determination of the total number of milli-equivalents of exchangeable hydrogen in a cation-exchange resin.

Procedure:

• Weigh into separate 100-mL beakers, three 2.00 g samples of material pretreated (Pretreatment done by passing 200ml of distilled water through sample in a filter tube)
• Rinse the weighed samples with water quantitatively into the filter tubes of the test apparatus. Fill the separating funnel with 1 L of HCl (1 + 9). Fill the sample tube with acid and tap to remove air bubbles. Attach the stem of the funnel to the filter tube with a suitable size rubber stopper. Pass the acid through the sample at a rate of 20 to 25 mL/min keeping the sample covered with acid at all times. Drain the liquid to the resin level and discard the effluent.
• Rinse the separating funnel thoroughly with water and then with isopropyl alcohol. Run isopropyl alcohol (200ml) through the acid-treated samples at a rate of 20 to 25 mL/min until 10 mL of the effluent collected in 10 mL of water is yellow to methyl orange or has a pH above 3.9.
• Transfer the filter tube to the top of a suction flask and drain the residual alcohol from the resin using a vacuum pump. Continue to aspirate until the sample is free flowing.
• Transfer the samples quantitatively to 500-mL flasks or bottles.
• Pipette in exactly 200 mL of standard NaOH solution (0.1 N) in NaCl.
• Stopper immediately and mix well. Allow samples to equilibrate for 16 h.
• Remix and allow the samples to settle. Pipet out three 50 mL portions of each sample taking the necessary precautions to avoid drawing resinous material up into the pipette. Titrate electrometrically with standard HCl (0.1 N) to a pH of 8.2 or calorimetrically using phenolphthalein indicator. Record the volume of HCl used in each titration to the nearest 0.01 mL. Use the average of the three titrations for each sample as F.

Cw=[(200xNB) -(FxNAx4)]/W
wherein:
Cw: total cation-exchange capacity in milliequivalents per wet gram
F = average mL of HCl required for the titration
W = wet grams of the sample
NA = normality of HCl used,
NB = normality of NaOH solution used

Surface area, pore size, pore volume – Using single point BET

The surface area, pore volume and pore size distribution of the samples were determined by N2 adsorption at 77 K using a Micromeritics Tristar II instrument. The samples were outgassed in vacuum for 4 h at 110 ºC before nitrogen adsorption.
Specific surface areas were calculated using the BET equation, and total pore volumes were evaluated from the nitrogen uptake at a relative N2 pressure of P/P0 = 0.99. The average pore diameter was calculated by 4V/A equation.

Crush strength, Maximum Axial force at break and Stiffness: Using dynamic rotational rheometer

Compressive strength analysis or crush strength analysis is evaluated using ARES G2 Rheometer in Axial mode. The transducer of ARESs G2 can be operated in axial mode, where a force up to 20 N can be applied to the sample at a very small rate. The spherical catalysts are place on the base plate and the top plate is moved towards the sample in a compressive mode at a very small rate of 0.005mm/sec. Once the top plate touches the spherical sample, the force is recorded against the displacement. The compression is continued till the sample is broken or the force reaches maximum value of 18 N. The maximum Force (N) at the time of breakage is defined as the Crush strength in (N). For the test for a batch, catalyst with similar dia in the range of 600-800 microns are preferred.

Particle size: Through sieving

This test method consists of resin through a series of standard sieves of progressively decreasing size of opening. The volume retained on each of the sieves is measured.

Sieve used:

1 Sieves, 2 mm (4 in.) in diameter, conforming to Specification E11. A suitable series of such sieves consists of 1.18-mm, 1-mm, 710-µm, 500-µm, 425-µm, 355-µm, 150-µm.

Make of the instrument: Fritsch

Procedure:
• Clean the sieves before use.
• Weigh the empty sieves individually (Make sure that the sieves are cleaned).
• Transfer the entire sample onto the sieve with the largest mesh.
• Place the sieves on the positioning pad and arrange the sieves from lower to higher sieve size from bottom to top.
• Secure the sieves by locking the side straps. Make sure that the sieves should not be loosened after locking.
• Set the amplitude to 1.0 and time of sieving to 30min.
• Start the program. During sieving the sample is subjected to vertical movement (vibratory sieving).
• After 30 min take out the sieves and weigh them individually.
• The difference between filled sieve and empty sieve gives the weight of the samples on that respective sieve.

Example 1: Preparation of Base Resin:

Macroporous poly- (styrene-co-divinylbenzene) is prepared by the suspension polymerization technique, using the n- heptanes porogen. Benzoyl peroxide was used as the initiator, and CMC was used as the suspension agent. In a typical polymerization, the reaction was carried out in a 2 L round bottomed jacketed glass reactor fitted with a mechanical stirrer and a condenser. Following recipe is used:

Aqueous Phase Monomer Phase Porogen
Water: 400 parts
CMC: 2 part
Sodium Chloride: 100 parts Total Monomer: 100 parts
Styrene: 60 parts
DVB: 40 parts
BPO: 1 part n-heptane = 50 parts

First, a solution of CMC, Sodium chloride in water at 65 °C was introduced into the reactor and heated for 2-3 hours till complete dissolution. The monomers, St, and DVB were mixed well to form the monomeric mixture, to which the BPO initiator was added in an amount. The required amount of porogen was added to this monomeric mixture to form the organic phase and then this was poured into the reactor to initiate the polymerization reaction. Polymerization was performed at 72°C for 1 hour, 80°C for 10 h and 88°C for 4 hours at a stirring speed of 450 rpm. After polymerization, the resulting copolymer beads were washed thoroughly with hot water and aqueous phase was removed by opening bottom drain valve. Residual progen was removed through vacuum distillation. Finally, the beads were dried under vacuum in an oven at 80°C for at least 24 h and then sieved for 425 micron to 1200 micron cut

Example 2: Sulfonation of base resin:

Suplhonation of Macroporous poly- (styrene-co-divinylbenzene) prepared in example-1 was done in 2 L round bottomed jacketed glass reactor. 100 parts of base resin is taken into reactor. 600 parts of 98% sulhuric acid was added and the suspension was stirred at 180rpm for 6 hours. After the reaction time the mixture was poured into the beaker placed in a freezing water bath in order to quench the reaction. Then the mixture was diluted with the addition of 50% sulphuric acid (200 mL) and then finally with deionised water (500 mL). The Sulfonated resin prepared was washed with water until neutral pH was obtained. The obtained resins were vaccum dried at 50?C for 8-10 hours.
Example 3: Sulfonation

The same procedure was followed as described in Example 2 but here the sulfonating agent used was 20% oleum and time for sulfonation was around 4 hours
Example 4- Sulfonation:

The same procedure was followed as described in Example 2 but here the sulfonating agent used was mixture of sulphuric acid and 20% oleum (50:50) and time for sulfonation was around 4 hours
Example 5- Sulfonation:

The same procedure was followed as described in Example 4 but here the base resin was swelled in dichloroethane prior to sulfonation and time for sulfonation was 3 hours.
The results obtained are tabulated below:

Example Dry Weight Acid capacity (eq/kg) Surface Area
(m2/g) Pore Size
(Ao) Pore Volume
(cm3/g) Crush Strength (N/mm) Maximum Axial force at break (g) Stiffness (N/mm) Thermal stability (deg C)
Example 2 4.7 41 282 0.288 130 1389 152 236
Example 3 5.5 44 292 0.280 36 499 286 225
Example 4 4.9 46 290 0.276 141 1766 281 237
Example 5 5.3 45 300 0.285 157 1823 304 254
Commercial catalyst 5.2 28 280 0.195 96 882 295 243

Technical advantages of the invention:

1. High crush strength of at least 150 N/mm
2. High ion exchange capacities > 5.2 eq/kg.
3. The resin aid catalyst particle size is >90% from 425 to 1200 micron ,CLAIMS:We Claim:
1. A two-step process for preparation of high crush strength high exchange capacity Resin acid catalyst, said process comprising the steps:
a. preparation of base resin:
i. heating a solution of water, suspending agent and sodium chloride till complete dissolution, to obtain an aqueous phase;
ii. mixing styrene and divinylbenzene (DVB), followed by addition of initiator benzoyl peroxide (BPO), and porogen to form an organic phase;
iii. mixing the aqueous phase and the organic phase, to initiate polymerization and obtaining reaction product;
iv. washing the reaction product with hot water, and removing the residual porogen by vacuum distillation;
v. drying copolymer beads under vacuum and sieving to obtain base resin;
b. Sulfonation of base resin:
i. suspending base resin in dichloroethane;
ii. treating swelled base resin with mixture of sulphuric acid and 20% oleum;
iii. washing sulfonated resin with water to neutralise pH, and vacuum drying to obtain resin acid catalyst.

2. The process as claimed in claim 1, wherein the resin acid catalyst is sulphonated copolymer of styrene and divinylbenzene.

3. The process as claimed in claim 1, wherein the solution in step (a) (i) is heated at temperature range of 60?C to 90?C, for 2-3 hours, wherein the mixture of aqueous phase and organic phase of step (a) (ii) is polymerised at temperature of 30 to 150?C, and stirred at 450 rpm; wherein the copolymer bead of step (a) (v) is vacuum dried in an oven at 80°C for at least 24 hour and sieved for 425 microns to 1200 microns cut.

4. The process as claimed in claim 1, wherein the mixture of aqueous phase and organic phase of step (a) (ii) is polymerised at 72°C for 1 hour, then at 80°C for 10 h and then at 88°C for 4 hours at a stirring speed of 450 rpm.
5. The process as claimed in claim 1, wherein the swelled base resin of step (b) (ii) is treated with sulphuric acid and 20% oleum; wherein the sulfonated resin of step (b) (iii) is vacuum dried at 50°C for 8-10 hours to obtain resin acid catalyst.

6. The process as claimed in claim 1, wherein the swelled base resin of step (b) (ii) is treated with sulphuric acid and 20% oleum (50:50) at 180 rpm for 4 hours.

7. The process as claimed in claim 1, wherein the divinylbenzene is in the range of 20 – 25 wt% of styrene.

8. The process as claimed in claim 1, wherein the molar concentration of free radical initiator is in the range of 0.01 to 5.0 % of the total weight of monomers.

9. The process as claimed in claim 1, wherein the free radical initiator is selected from group of peroxides, proxy-compounds, azo compounds, or mixture thereof.

10. The process as claimed in claim 1, wherein the free radical initiator is benzoyl peroxide (BPO).

11. The process as claimed in claim 1, wherein the porogen or pore forming agent is selected from group of aromatic compounds, halogenated solvents, plasticisers, polymers, or mixture thereof.

12. The process as claimed in claim 1, wherein the porogen or pore forming agent is n-heptane, toluene, or mixture thereof.

13. The process as claimed in claim 1, wherein the volume fraction of porogen or pore forming agent is about 35%.

14. The process as claimed in claim 1, wherein the suspending agents is selected from polyvinylalcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, poly (vinyl pyrrolidine), polyacrylate salts, polymethyacrylate salts, dimethyldialkylammonium polymers, nitrite and dichromatic salts, calcium phosphate salts, carbonate salts, sulfate salts, bentonite clays, gum arabic, lignosulfonates, gelatine, xanthan gums and mixture thereof, preferably carboxymethyl cellulose (CMC).

15. The process as claimed in claim 1, wherein the suspending agents is in range of 0.01 to 0.5 % of total weight of the monomers.

16. The process as claimed in claim 1, wherein the base resin is suspended in the swelling agent for about 1 to 8 hours.

17. The process as claimed in claim 1, wherein the conversion of base resin to resin acid catalyst is greater than 95 %.

18. The process as claimed in claim 1, wherein the resin acid catalyst is in range of 300 to 1500 micron, with 90% particles having particle size in range of 425to 1200-micron, surface area in range of 10 to 100 m2/g, pore size in range of 200 to 300 Å, pore volume in range of 0.2 to 0.8 cm3/g.

19. The process as claimed in claim 1, wherein the resin acid catalyst is having crush strength of atleast 150 N/mm, and ion exchange capacities in range of 4.9 to 5.5 eq/kg, preferably > 5.2 eq/kg.