FORM2
THEPATENTS ACT, 1970
(39 of 1970)
&
THEPATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: MANNITOL BASED GELATORS FOR OIL SPILLAGE
APPLICATIONS
2. Applicant(s)
NAME NATIONALITY ADDRESS
HINDUSTAN PETROLEUM
CORPORATION LTD.
Indian Hindustan Petroleum Corporation
Ltd, Petroleum House, 17
Jamshedji Tata Road, Churchgate,
Mumbai 400020, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.
1
2
TECHNICAL FIELD
[0001] The subject matter described herein in general relates to sugar-based compounds that are
able to form gels. The subject matter further relates to methods of making the sugar-based
compounds, and gels including such compounds. The sugar-5 based compounds can be used to
control hydrocarbon spill by gel formation. The subject matter further relates to methods for
recovery of hydrocarbons and the sugar based compounds from the gel.
BACKGROUND
[0002] A gel can be defined as a solution in which the solid, also known as a gelator, is meshed
10 to form a rigid or semi-rigid mixture results. Depending on the structural nature of gel networks,
gels can be simply divided into chemical gels and physical gels. In the case of chemical gels, the
aggregation units at different levels are connected into three-dimensional networks via covalent
bonds whereas in physical gels, the molecules of a gelator aggregate into network structure via
various non-covalent interactions, which are considerably weaker than covalent bonds.
15 [0003] Physical gelation of water and solvents include polymers, micro- or nano-particles, and
low-molecular mass organic compounds (LMMGs). The gels formed by latter are named
supramolecular gels or molecular gels and can be used for gelation of oil from oil–water
mixtures for oil spill recovery. The spilled oil is transformed from a liquid into semi-solid or
rubber-like materials floating on the surface of water by introducing LMMGs into the oil
20 contaminated water.
[0004] Kar and co-workers have disclosed supramolecular hydrogelation of a composite
including single walled nanotubes (SWNTs) and amphiphilic dipeptide carboxylates (Chem.
Commun., 2012, 48, 8389–8391).
[0005] Kar and co-workers have disclosed dipeptide-based long-chain acids/salts capable of
25 efficiently gelating organic solvents and water. The xerogels prepared from the organogels
showed time-dependent adsorption of dyes such as crystal violet (Langmuir 2009, 25(15), 8639–
8648).
3
SUMMARY
[0006] The present disclosure relates to a compound having the Formula:
Formula I
wherein, R1and R2 are independently selected from C1 to C10 alkyl. The 5 present disclosure also
relates to a method of preparing the compound of Formula I.
[0007] The present disclosure further relates to a gel comprising a compound of Formula I and a
solvent. The present disclosure further relates to a method of producing a gel comprising
contacting the compound of Formula I with a solvent.
10 [0008] The present disclosure further relates to a method of containing the spill of a
hydrocarbon, the method comprising contacting the hydrocarbon with the compound of Formula
I to obtain a gel. The present disclosure further relates to a method of reclaiming solvent from the
gel comprising a compound of Formula I and a solvent.
[0009] These and other features, aspects and advantages of the present subject matter will be
15 better understood with reference to the following description and appended claims. This
summary is provided to introduce a selection of concepts in a simplified form. This summary is
not intended to identify key features or essential features of the claimed subject matter, nor is it
intended to be used to limit the scope of the claimed subject matter.
20 DETAILED DESCRIPTION
[0010] Those skilled in the art will be aware that the present disclosure is subject to variations
and modifications other than those specifically described. It is to be understood that the present
disclosure includes all such variations and modifications. The disclosure also includes all such
steps, features, compositions and compounds referred to or indicated in this specification,
4
individually or collectively and any and all combinations of any or more of such steps or
features.
Definitions
[0011] For convenience, before further description of the present disclosure, certain terms
employed in the specification, and examples are collected here. These definitions 5 should be read
in the light of the remainder of the disclosure and understood as by a person of skill in the art.
The terms used herein have the meanings recognized and known to those of skill in the art,
however, for convenience and completeness, particular terms and their meanings are set forth
below.
10 [0012] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at
least one) of the grammatical object of the article.
[0013] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning
that additional elements may be included. Throughout this specification, unless the context
requires otherwise the word “comprise”, and variations, such as “comprises” and “comprising”,
15 will be understood to imply the inclusion of a stated element or step or group of element or steps
but not the exclusion of any other element or step or group of element or steps.
[0014] The term “including” is used to mean “including but not limited to”. “Including” and
“including but not limited to” are used interchangeably.
[0015] The term "hydrocarbon(s)" refers to organic compounds that are made of hydrogen and
20 carbon atoms. The source of the hydrocarbons may be from crude oils and refined petroleum
products. Crude oil and other petroleum fractions may include compounds with hetero atoms like
nitrogen, oxygen, sulfur, halogens and metallic elements along with hydrocarbons.
[0016] The term "gel" refers to a colloidal suspension of a solid dispersed in liquid and appears
like semi solid.
25 [0017] The term “CRN” means cracked run naptha (mainly comes from the Fluidized Catalytic
Cracking (FCC) unit in the refinery).
[0018] The term “SRN” means straight run naphtha, which comes from direct distillation of
crude oil.
[0019] The term “diesel” means a specific fractional distillate of petroleum crude oil between
30 200 °C and 350 °C at atmospheric pressure.
5
[0020] Ratios, concentrations, amounts, and other numerical data may be presented herein in a
range format. It is to be understood that such range format is used merely for convenience and
brevity and should be interpreted flexibly to include not only the numerical values explicitly
recited as the limits of the range, but also to include all the individual numerical values or subranges
encompassed within that range as if each numerical value and sub-5 range is explicitly
recited. For example, a temperature range of about 140°Cto about 180°Cshould be interpreted to
include not only the explicitly recited limits of about140°C to about 180°C, but also to include
sub-ranges, such as 145°C to 155 °C, 150°C to 170°C, and so forth, as well as individual
amounts, including fractional amounts, within the specified ranges, such as 142.2°C, 140.6°C,
10 and 141.3°C, for example.
[0021] The present disclosure relates to a class of amphiphilic gelators which can be used for
dual purpose as oil or hydrocarbon removal from water. These absorbed hydrocarbons can be
easily recovered from the gel including the amphiphilic gelators and oil by heating the gel. The
gelators have the potential for selective extraction of oil in water systems and water in oil
15 systems. In one implementation, the present disclosure relates to a compound having the
Formula:
Formula I
wherein, R1and R2 are independently selected from C1 to C10 alkyl.
20 [0022] The present disclosure also relates to a method of preparing the compound of Formula I.
[0023] The molecular gelators of Formula I can be used for the containment of spilled refinery
products such as straight run naphtha, gasoline, diesel fractions and crude oil individually and as
a mixture of oil and water emulsion.
[0024] The compounds of Formula I can be used for remediation of a release of spilled crude oil
25 or hydrocarbon.
6
[0025] In one implementation, the present disclosure relates to a compound having the Formula:
Formula I
wherein, R1 and R2 are C1-C8 alkyl.
[0026] In another implementation, the present disclosure relates 5 to a compound having the
Formula:
Formula I
wherein, R1 and R2 are C1 to C5 alkyl.
10 [0027] In yet another implementation, the present disclosure relates to a compound having the
Formula:
Formula I
wherein, R1 and R2are C5alkyl.
7
[0028] In one implementation, the present disclosure relates to a compound having the Formula:
Formula I
wherein, R1and R2 are C1 alkyl.
[0029] In one implementation, the present disclosure relates to a compound 5 having the Formula:
Formula I
wherein, R1 and R2 are C2 alkyl.
[0030] In another implementation, the present disclosure relates to a compound having the
10 Formula:
Formula I
wherein, R1 is C1 alkyl and R2 is C2 alkyl.
8
[0031] In one implementation, the present disclosure relates to a compound having the Formula
shown below with the substituents provided in the Table 1:
5 Table 1
Compound IUPAC names R1 R2
1 (1,2-bis(2,2-dimethyl-1,3-dioxolan-4-
yl)ethane-1,2-diol)
-CH3 -CH3
2 (1,2-di(1,4-dioxaspiro[4.5]decan-2-
yl)ethane-1,2-diol)
-(CH2)5 -(CH2)5
3 (1,2-bis(2-ethyl-2-methyl-1,3-dioxolan-4-
yl)ethane-1,2-diol)
-CH3 -CH2CH3
4 (1,2-bis(2,2-diethyl-1,3-dioxolan-4-
yl)ethane-1,2-diol)
-CH2CH3 -CH2CH3
[0032] In one implementation, the present disclosure provides a process for the preparation of
compound of Formula I, comprising the steps of; adding mannitol in a solvent to obtain a
suspension, mixing the reagent with a reactant to obtain a solution, and stirring the suspension
10 with the solution to at 50-600C for 1-3 hrs obtain the desired product.
[0033] In another implementation, the reagent is selected from the group consisting of p-TsOH
and dodecyl benzene sulfonic acid.
[0034] In one implementation, the solvent is selected from the group consisting of dimethyl
formamide and dimethyl sulfoxide.
15 [0035] In another implementation, the reactant is selected from the group consisting of 2,2-
dimethoxy propane, 1,1-dimethoxycyclohexane, 2,2-dimethoxybutane and 3,3-
dimethoxypentane.
9
[0036] In one implementation, the compounds of Formula I and gels synthesized therefrom can
be used in applications, suchas tissue engineering, drug delivery, separation of biomolecules, and
stimulus-responsive advanced materials.
[0037] The compounds of Formula I can be used to form gels having numerous applications. In
one implementation, the compounds of Formula I can be added to one o 5 r more solvents in order
to produce a gel. In another implementation, the compounds of Formula I can be added to a
solvent in order to produce a gel. The present disclosure also relates to method for producing a
gel comprising contacting the compound of Formula I with a solvent. The term solvent refers to
a polar solvent, non-polar solvent and mixtures thereof. In another implementation, the solvent
10 comprises water, an organic solvent, or mixtures thereof. Solvents can be nonpolar such as, for
example, hydrocarbons like pentane, cyclopentane, hexane, cyclohexane, benzene, toluene,
xylene, 1,4-dioxane, chloroform, diethyl ether or mixtures thereof. In one implementation, the
solvents can be polar, aprotic solvents such as, for example, dichloromethane, tetrahydrofuran,
ethyl acetate, acetone, dimethylformamide, acetonitrile, pyridine, carbon disulfide, benzonitrile,
15 or dimethyl sulfoxide. In another implementation, the solvent can be polar protic solvents such as
alcohols and carboxylic acids including, but not limited to, formic acid, n-butanol, isopropanol,
n-propanol, ethanol, methanol, acetic acid, ethylene glycol, propylene glycol, glycerin, or water.
Mixtures of solvents can also be used herein. In one implementation, the solvent can be a
mixture of water with a hydrocarbon. In another implementation, the solvent is a hydrocarbon. In
20 another implementation, the solvent is selected from crude oil, or a petroleum product.
[0038] The present disclosure also relates to method of containing the spill of a hydrocarbon, the
method comprising contacting the hydrocarbon with the compound of Formula I to obtain a gel.
[0039] In one implementation, a method of recovering crude oil, or petroleum product from a
spill of crude oil, or the petroleum product comprises: (a) forming a gel comprising the crude oil,
25 or the petroleum product and a compound of formula I; (b) collecting the gel; and (c) reclaiming
the crude oil or the petroleum product from the gel.
[0040] In another implementation, method of reclaiming solvent and a compound of Formula I
from the gel comprising the solvent and the compound of Formula I.
Examples
30 [0041] The disclosure will now be illustrated with working examples, which is intended to
illustrate the working of disclosure and not intended to take restrictively to imply any limitations
10
on the scope of the present disclosure. Other examples are also possible which are within the
scope of the present disclosure.
Example 1
Synthesis of compound of Formula I
[0042] The compounds of Formula I were synthesized 5 according to Scheme 1.
Scheme 1
[0043] Compounds 1-4 are bis-acetals of mannitol where four hydroxyl groups are protected by
10 aliphatic ketones. These mannitol based gelators were synthesized by Scheme 1. To a suspension
of mannitol (5 g, 27.5 mmol) in dry DMF (100 mL), 2,2-dimethoxy propane (6.7 ml, 55 mmol)
and p-TsOH (1 g, 5 mmol) were added. The resulting mixture was stirred at 60 ºC for 2h. After
the completion of the reaction, the solvent was removed. The resulting mixture was dissolved in
EtOAc and the organic phase was washed by NaHCO3 solution followed by brine. The organic
15 phase was collected, and then dried with MgSO4 and evaporated under reduced pressure to
obtain white viscous liquid. The material thus obtained was purified by column chromatography
using hexane: ethyl acetate as the eluent. The product (Compound 1) was obtained as a white
solid in 85% yield. 1H NMR (500 MHz, CDCl3, rt): δ =4.21-4.08 (m, 4H), 3.99-3.94 (m, 2H), 3.76-
3.71 (m, 2H), 1.41 (s, 6H), 1.35 (s, 6H).
20 [0044] Compound 2 was synthesized following the reaction procedure as that of compound 1 but
using 1,1-dimethoxycyclohexane (7.9 g, 55 mmol) instead of 2,2-dimethoxy propane. The
reaction was performed for 2 hours. The mixture thus obtained after reaction was subjected to
column chromatography using hexane: ethyl acetate as the eluent to isolate the product was as a
white solid in 59% yield.1H NMR (500 MHz, CDCl3, rt): δ =4.17-4.13 (dd, 2H), 4.04-4.0 (dd, 2H ),
25 3.87-3.83 (dd, 2H), 3.38-3.34 (m, 2H), 1.54-1.49 (m, 20H).
[0045] Compound 3 was synthesized following the reaction procedure as that of compound 1 but
using 2,2-dimethoxybutane (6.4 g, 55 mmol) instead of 2,2-dimethoxy propane. The reaction
11
was performed for 5 hours. The mixture thus obtained after reaction was subjected to column
chromatography using hexane: ethyl acetate as the eluent to isolate the product was as a white
solid in 51% yield. 1H NMR (500 MHz, CDCl3, rt): δ =4.25-4.1 (m, 4H), 4.08-4.03 (m, 2H), 3.83-
3.77 (m, 2H), 1.71-1.67(q, 4H), 1.43 (s, 6H), 0.99-0.95 (t, 6H).
[0046] Compound 4 was synthesized following the reaction procedure as 5 that of compound 1 but
using 3,3-dimethoxypentane (7.2 g, 55 mmol) instead of 2,2-dimethoxy propane. The reaction
was performed for 5 hours. The mixture thus obtained after reaction was subjected to column
chromatography using hexane: ethyl acetate as the eluent to isolate the product was as a white
solid in 53% yield. 1H NMR (500 MHz, CDCl3, rt): δ =4.26-4.12 (m, 4H), 4.10-4.03 (m, 2H), 3.85-
10 3.79 (m, 2H), 1.87-1.67 (m, 8H), 0.95-0.87 (t, 12H).
Example 2
Gelation Study with crude oil
[0047] In a typical procedure, the gelator compound of Formula I was added to 0.5 ml of crude
oil in a glass vial with an internal diameter (i.d.) of 10 mm. The mixture was warmed gently to
15 dissolve the solid compound in crude oil. Then the solution was allowed to cool slowly to room
temperature without disturbance. After few minutes, the solid aggregate mass was found to be
stable to inversion of the glass vial, and then the compound was recognized to form a gel.
[0048] To calculate minimum gelation concentration (MGC), gelator is added gradually from 1
mg to higher amount in required solvent/oil (0.5 ml) and the above process (heating and cooling)
20 was repeated until gel was formed.
[0049] Gel melting temperature was determined by typical tube inversion method. The vial
containing the gel, as prepared above was immersed in the oil-bath ‘upside down’ and slowly
heated. The temperature at which the viscous gel melted down was recorded as Tgel.
Gelation Study with other oils and solvents
25 [0050] The gelation process for crude oil was repeated taking CRN, SRN and Diesel as refinery
distillates and taking hexane, octane, dodecane, hexadecane, benzene, toluene and xylene as
solvents (Table 3-5).
12
Table 3: Gelation abilities of compound of Formula I in different hydrocarbon solvents
Compound 1 2 3 4
MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC
Hexane 0.7 142.8 0.42 238.0 0.71 140.8 0.65 153.8
Octane 0.56 178.5 0.4 250.0 0.6 166.6 0.58 172.4
Dodecane 0.55 181.8 0.36 277.7 0.52 192.3 0.47 212.7
Hexadecane 0.51 196.0 0.35 285.7 0.5 200.0 0.43 232.5
Benzene 2 50 S … 1.97 50.7 2.1 47.6
Toluene 1.6 62.5 S … 1.72 58.1 1.86 53.7
Xylene 1.4 71.4 S … 1.64 60.9 1.78 56.1
MGC = Minimum Gelation Concentration (amount in g of gelator required for 100 ml
of hydrophobic material to be gelated), MUC = Minimum Uptake Capability (volume
in ml of hydrophobic material gelated by 1 g of gelator), S = Soluble
[0051] The above synthesized compounds can be classified as mannitol compounds with
aliphatic carbonyls as 1,2:5,6-capped acetals or ketals. Gelation ability of compounds 1-4 in
different solvents are tabulated in Table 3. Compounds 1-4 show 5 very good gelation ability with
paraffinic solvents as well as with aromatic solvents. Minimum uptake capability of these
gelators toward paraffinic solvents vary in between 140 to 280 times whereas that for aromatic
solvents vary in between 45 to 70 times and even compound 2 was unable to form gel with
aromatic solvents. Thus, their gelation ability is superior for paraffinic solvents than the aromatic
10 solvents. Increasing the carbon chain length in the capping carbonyl part (moving from acetone
in 1 to cyclohexanone in 2via methyl ethyl ketone in 3 and diethyl ketone in 4) increases gelation
ability for paraffinic solvents (MGC value 0.7 of 1 for hexane vs 0.42 of 2).The same trend is
followed for aromatic solvents (MGC value 2.0 of 1 for benzene vs. 1.86 of 4).
[0052] In general, for all of these gelators, paraffinic solvents having higher molecular weight
15 have lower MGC (for 1 MUC of 142.8 for hexane vs. MUC of 196.0 for hexadecane) i.e. higher
13
the paraffinic chain length higher is the gelation ability. The same conclusion can be drawn for
aromatic solvents also where with successive addition of alkyl chain to benzene ring gelation
ability is increased. Superior gelation affinity of compounds 1-4 towards paraffinic solvents may
be correlated to their structural motif. As all seven compounds are originated from mannitol by
protection of four hydroxyl groups out of six, the capping groups 5 as hydrophobic part in these
gelator compounds play the major role for their distinction behaviour. Compounds 1-4 are
having alkyl capping groups like paraffinic solvent for gelation.
Table 4: Gelation abilities of compound of Formula I in different oils
Compound 1 2 3 4
MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC
CRN 1.36 73.5 1.2 83.3 1.2 83.3 1.15 86.9
SRN 1.0 100 2.05 48.7 0.97 103.0 0.9 111.1
Kero 0.78 128.2 0.56 178.5 0.67 149.2 0.63 158.7
Diesel 0.47 212.7 0.42 238.0 0.45 222.2 0.45 222.2
Crude 2.13 46.9 1.92 52.0 2.05 48.7 2 50
Vegetable oil 2.0 50 1.85 54.0 1.92 52.0 1.9 52.6
MGC = Minimum Gelation Concentration, MUC = Minimum Uptake Capability
10 [0053] After successful application of these gelators with different solvents they were applied
over mineral oils and vegetable oil to verify their gelation ability. Along with crude oil, different
refinery distillates also converted to gel by the gelator compounds as depicted in Table 4. As
compounds 1-4 have gelation ability with paraffinic as well aromatic solvents they form gel with
all refinery fractions and with crude oil. Gelation efficiency of 1-4 for different oils follows the
15 same trend of 2>4>3>1 as observed in Table 3 i.e. increasing capping chain length increases
gelation ability. As we move from lighter fractions to heavier fractions (from SRN to Diesel via
Kero) aliphatic chain length increases gradually resulting successive increment of gelation ability
as expected from previous findings from Table 3. Thus heavier refinery distillates are easily
14
gelated than the lighter distillates. Again these compounds are easy to gelate paraffinic solvents
than aromatic solvents; that effect is reflected in between SRN and CRN where the later having
greater percentage of aromatic content is tough to be gelated. Crude oil having complex
composition have poor gelation tendency than its various fractions where minimum uptake
capability for crude oil was found to be in 5 between 47 to 57 times.
Table 5: Gelation abilities of compound of Formula I in different crude oils
Compound 1 2 3 4
MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC
C1(API = 18.8) 2.36 42.3 2.25 44.4 2.35 42.5 2.3 43.4
C2 (API = 27.1) 2.25 44.4 2.16 46.2 2.2 45.5 2.22 45.0
C3 (API = 28.1) 2.22 45.0 2.15 46.5 2.19 45.6 2.17 46.0
C4 (API = 35.5) 2.13 46.9 1.92 52.0 2.05 48.7 2.0 50
C5 (API = 40.5) 2.1 47.6 1.93 51.8 2.0 50 2.1 47.6
MGC = Minimum Gelation Concentration, MUC = Minimum Uptake Capability
[0054] In order to check the effect of the composition of crude oil on the gelation ability of the
gelator compounds, experiments were conducted with crudes with varying API gravities ranging
10 from very low API (C1, 18.8��) to high API (C5, 40.5��). Table 5 describes the effect of API
gravity (crude composition) on the uptake (MGC) capability of the gelators. Gelation ability of
compounds 1-4 follow the same order as observed before. It is evident from Table 5 that heavy
crude (lower API) have higher MGC and lighter crude (higher API) have lower MGC. Thus,
uptake capability decreased with increase in API gravity i.e. higher the resin & asphaltene in the
15 crude, lower the API gravity, thereby a reduction in the uptake capacity by the gelators was
observed. These findings indicate that the composition of crude oil played a major role in the oil
uptake by the gelator compounds. However, highest MUC value for heaviest crude of 37.4 and
that for lightest crude of 51.8 is quite remarkable regarding compositional complexities of crude
15
oils. This study clearly indicated that the gelator could be used for the most of the crudes
covering the wide spectrum of crude basket available from different parts of the globe.
Example 4
Selective Gelation of crude oil from a Biphasic Mixture of Oil and Water
[0055] In a typical procedure, 0.5 mL of crude oil and 0.5 mL of water 5 were taken in a sample
tube to which required amount of the gelator compounds of Formula I (as required to attain at
least MGC) was added (Table 4). The gelator was then solubilized in this two-phase solution by
heating. After the mixture was cooled to room temperature, the crude oil layer was gelated,
keeping the water layer intact in the liquid state. The same process was followed for other oils
10 like CRN, SRN, Kero, diesel and vegetable oil.
Table 6: Gelation abilities of compound of Formula I in various oil-water mixtures
Compound 2 4 Compound 2 4
MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC MGC
(%w/v)
MUC
CRN-Water 1.25 80.0 1.3 76.9 CRN-sea Water 1.25 80.0 1.3 76.9
SRN-Water 2.0 50.0 1.0 100 SRN- sea Water 2.02 49.5 1.05 95.2
Kero-Water 0.6 166.6 0.7 142.8 Kero- sea Water 0.6 166.6 0.73 136.9
Diesel-Water 0.5 200 0.55 181.8 Diesel- sea Water 0.5 200.0 0.55 181.8
Crude-Water 2.0 50.0 2.1 47.6 Crude- sea Water 2.0 50.0 2.15 46.5
Veg oil-
Water
2.0 50.0 2.0 50 Veg oil- sea
Water
2.0 50.0 2.05 48.7
MGC = Minimum Gelation Concentration, MUC = Minimum Uptake Capability
[0056] Selective gelation of oil from a biphasic mixture of oil and water was performed and the
results are noted in Table 6. Six oil samples containing crude oil, refinery distillates as well as
15 vegetable oil were subjected for gelation experiment prior to practical application in oil spillage.
Compound 1 and 3 were unable to display phase selective gelation. In presence of water 1 and 3
were unable to form gel with the oil phase. This phenomenon is due to partial solubility of these
16
diol compounds in water where presence of small alkyl chain in the capping carbonyl is not
providing sufficient hydrophobicity to prevent water solubility. But with increasing alkyl chain
length i.e. hydrophobicity compounds 2 and 4 are able to exhibit selective oil phase gelation.
These gelators were able to gelate exclusively the oil phase without altering the water phase
during performance evaluation gelation experiments. Gelation abilities 5 of the gelators follow the
same order as reported in Table 4. Gelation of all oils was successful and there was no significant
alteration in their gelation abilities in the biphasic mixture as compared to that of individual oils.
MGCs for all mineral oils along with vegetable oil were increased slightly not more than 0.2 %
(w/v) from their respective individual/single phase studies. Thus, oil over water can be contained
10 using these gelators leaving water as unaffected.
Example 5
Selective Gelation of crude oil from a Biphasic Mixture of Oil and Salt Solution:
[0057] In a typical procedure, 0.5 mL of crude oil and 0.5 mL of 3.5% of NaCl solution
(equivalent salt concentration to that of sea water) were taken in a sample tube to which required
15 of the gelator compound of Formula I was added. The gelator was then solubilized in this twophase
solution by heating. After the mixture was cooled to room temperature, the crude oil layer
was gelated, keeping the water layer intact in the liquid state. The same process was followed for
other oils like CRN, SRN, Kero, diesel and vegetable oil.
[0058] Oil Selective gelation of oils from a biphasic mixture of oil and sea water was also
20 performed and the results are tabulated in Table 6. Similar to previous oil-water phase study
compound 1 and 3 didn’t show phase selective gelation of oil phase in presence of sea water but
other compounds were able to do so. Other gelator compounds were able to gelate exclusively
the oil phase without altering the sea water phase during performance evaluation gelation
experiments. Comparison of the results from Table 6 clearly dictates that even under highly
25 saline conditions MCG & MUC for those oils remained almost unchanged. Thus, strength and
capability of the organogelators towards the gelation preference for organic phase is highly
encouraging even under extreme conditions reveling practical application towards oil spillage
over sea.
17
Example 6
Room Temperature Gelation of Crude Oil from a Biphasic Mixture of Oil and Salt
Solution:
[0059] For the phase selective gelation purpose volatile and oil miscible solvent dichloromethane
(DCM) was used. In a typical procedure 10% solution of the gelator 5 was prepared by dissolving
it in DCM at room temperature without applying heat. To a 25 ml of crude oil layer over 100 ml
of salt solution the gelator solution was applied to ensure complete dispersion. Within a few
minutes volatile DCM is evaporated and the crude oil layer is transformed to the gel state.
[0060] Utilizing the volatile solvent e.g. DCM, phase selective gelation of crude oil as well as
10 other oil fraction are possible. The advantage of this process is that without applying any heating
and cooling process phase selective gelation is possible making the process very much
economical. Thus the process can be applied for larger scale for practical remediation of oil
spillage. Generally use of other hydrophobic solvent e.g. toluene, diesel or SRN for phase
selective gelation require excess amount of gelator to congeal the oil phase as well as carrier
15 solvent but, applying our above said process these drawbacks can be neglected and maximum
efficiency can be achieved
Example 7
Oil Spill Recovery:
[0061] Oil spill recovery was performed taking 10 ml of SRN over 20 ml of water. Solution of
20 the compound of Formula I in DCM (0.25 g in 5 mL of DCM, 5 w/v%; only 1.5 ml of the DCM
solution was used for 10 ml of SRN) was added to the SRN-water mixture and allowed to stand
for about 15 min where SRN phase was transformed to the gel keeping the water layer intact in
the liquid state. The gel phase was filtered off and processed to recover the oil.
Example 7
25 Reclaiming solvent from Gel
[0062] 10 ml of SRN was transformed into gel phase using 150 mg of compound of Formula I as
described earlier. The gel was then subjected to vacuum distillation for oil phase recovery. After
18
successful distillation 8.9 ml of SRN was recovered leaving white powder of the gelator
compound with 89% of solvent recovery. The vacuum distillation was carried out at 60oC for 1
hour.
Advantages gained in the example illustrative process in this subject matter:
[0063] Environmentally benign sugar based phase selective gelator 5 has been developed for oil
phase gelation from a mixture of oil and water. The gelators efficiently work even at a very low
concentration and at room temperature. The gelators find application in marine oil spill recovery.
Oil from the gel can be recovered and gel can be recycled and reused for number of cycles
without loss of activity
10 [0064] Although the subject matter has been described in considerable detail with reference to
certain examples and implementations thereof, other implementations are possible. As such, the
spirit and scope of the appended claims should not be limited to the description of the preferred
examples and implementations contained therein.
15
20
25
19
I/We Claim:
1. A compound having the Formula:
5 Formula I
wherein,
R1 and R2 are independently selected from C1 to C10 alkyl.
2. The compound as claimed in claim 1, wherein R1 and R2 are C1-C8alkyl.
3. The compound as claimed in claim 1, wherein R1 and R2areC1-C5alkyl.
10 4. The compound as claimed in claim 1, wherein R1 and R2 are C5alkyl.
5. The compound as claimed in claim 1, wherein R1 and R2 are C1alkyl.
6. The compound as claimed in claim 1, wherein R1 and R2 are C2alkyl.
7. The compound as claimed in claim 1, wherein R1 is C1 alkyl and R2 is C2 alkyl.
8. A method of preparing the compound as claimed in claim 1.
15 9. A gel comprising a compound as claimed in claim 1 and a solvent.
10. The gel as claimed in claim 9, wherein the solvent is selected from water, an organic
solvent, or mixtures thereof.
11. A method for producing a gel comprising contacting the compound as claimed in claim
1 with a solvent.
20 12. The method as claimed in claim 11 wherein the solvent is selected from water, an organic
solvent, or mixtures thereof.
13. The method of claim 11, wherein the solvent is a hydrocarbon.
14. The method of claim 11, wherein the solvent comprises a mixture of a hydrocarbon and
water.
25 15. A method of containing the spill of a hydrocarbon, the method comprising contacting the
hydrocarbon with the compound as claimed in claim 1 to obtain a gel.
20
16. A method of reclaiming solvent and a compound as claimed in claim 1 from the gel as
claimed in claim 9.