DESC:FIELD
The present disclosure relates to organic gelators.
DEFINITIONS
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which it is used indicates otherwise.
Organic Gelator: The term “organic gelators” refers to organic substances that are capable of forming a gel.
Acetalization reaction: The term “Acetalization reaction” is an organic reaction that involves the formation of an acetal by nucleophilic addition of an alcohol to a ketone or an aldehyde.
Organogels: Organogels are semi-solid systems (soft materials) in which a three-dimensional network composed of cross-linked gelator fibers immobilizes an organic liquid.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Oil spills include any spill of crude oil or oil distilled products, such as gasoline, diesel fuels, jet fuels, kerosene, hydraulic oils, and lubricating oils that can pollute the surface of the land, air, and water environments.
Oil spills have a detrimental effect on the environment and living organisms, including humans, due to the environmental discharge of various organic compounds that make up crude oil and oil distillate products. Oil spills can have disastrous and long standing consequences on the environment.
Cleanup and recovery from an oil spill is difficult and depends upon many factors, such as the type of oil spilled, the temperature of the water, and the types of shorelines and beaches involved. Physical cleanup of oil spills are also very expensive.
One of the first gelators reported in literature is 1,3:2,4-Dibenzylidene-D-sorbitol (DBS)(CAS No. 19046-64-1), forms gel with organic solvents. However, DBS has the potential to gel an unusually large selection of organic solvents and is non discriminatory. Also, comparatively a larger amount of DBS (5 wt% or more) is required for effective gelation of the organic liquid.
Therefore, there is felt a need for an alternative method for preparing a gelator that is specific and selective for specific organic liquids, and also gelation of organic liquids can be performed using relatively less amount (4 wt% or less) of the gelator.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide an organic gelator.
Still another object of the present disclosure is to provide a simple process for preparation of organic gelators.
Yet another object of the present disclosure is to provide a process for jellifying an organic liquid.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY
The present disclosure relates to organic gelators. In one aspect, the present disclosure provides an organic gelator represented by of Formula (I):

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group. The organic gelator of the present disclosure has melting point in the range of 60 to 120 °C.
In a second aspect, the present disclosure provides a process for preparing an organic gelator of Formula (I), which involves alkylation of a hydroxybenzaldehyde of Formula (II),

Formula (II)
wherein R1 is selected from C1-C2 alkyl group,
by slow addition of C3-C18 alkyl bromide to a mixture of hydroxybenzaldehyde of Formula (II), and an potassium carbonate in dimethylformamide, under stirring at room temperature, to obtain a slurry comprising dialkoxybenzaldehyde of Formula (III),

Formula (III)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group.
Dialkoxybenzaldehyde of Formula (III) is separated from the slurry. A mixture of dialkoxybenzaldehyde of Formula (III), D-sorbitol, a catalyst and a fluid medium is heated to reflux to obtain a product mixture comprising organic gelator of Formula (I), which is cooled to allow the organic gelator Formula (I) to precipitate and then the product mixture is filtered, under reduced pressure, to obtain the organic gelator of Formula (I).
In a third aspect, the present disclosure provides a process for jellifying an organic liquid, by adding 2.5 to 4 wt% of an organic gelator of Formula (I),

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group,
to 1 ml of an organic liquid, under stirring, to obtain a resultant mixture, which is heated to a temperature in the range of 40 to 70 °C, and then cooled, without disturbance, to room temperature to obtain an organogel.
DETAILED DESCRIPTION
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
One of the first gelators reported in literature is 1,3:2,4-Dibenzylidene-D-sorbitol (DBS)(CAS No. 19046-64-1), forms gel with organic solvents. However, DBS has the potential to gel an unusually large selection of organic solvents and is non discriminatory. Also, comparatively a larger amount of DBS (5 wt% or more) is required for effective gelation of the organic liquid.

The inventors of the present disclosure have surprisingly found that introduction of specific substituents on the aromatic moiety of the DBS molecule, provides highly versatile, responsive, and selective organic gelators. The critical amount of the organic gelators of the present disclosure, required for forming gel with organic liquids is lower, in the range of 2.5 to 4 wt% of the total amount of gel.
The ability of organic gelators to form ‘solid-like’ gel phase colloidal materials with organic liquids is primarily controlled by the solubility and compatibility of these organic gelators with the organic liquids. Thus, an organic gelator must be sufficiently soluble for it to be compatible with the solvent, but sufficiently insoluble for self-assembly into a ‘solid-like’ network to be desirable.
Different alkyl chains are introduced to the aromatic backbone to tune the polarity of the organic gelator and thereby its solubility in organic liquids. Introducing a longer alkyl chain to the aromatic backbone of the organic gelator, lowers the polarity of the organic gelator as compared to the organic gelator having a shorter alkyl chain on the aromatic backbone of the organic gelator.
The present disclosure envisages organic gelators, which are specific and selective for specific organic liquids, and also gelation of organic liquids can be performed using relatively less amount (4 wt% or less), for removing oil spills on land or water.
In a first aspect of the present disclosure, there is provided an organic gelator.
The organic gelator of the present disclosure is represented by Formula (I):

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group.
In accordance with the embodiments of the present disclosure, C1-C2 alkyl group is selected from methyl and ethyl, and C3-C18 alkyl group is selected from n-propyl, n-butyl, n-heptyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl and n-octadecyl.
Typically, the different alkyl chains are introduced to the aromatic backbone to tune the polarity of the organic gelator. A longer alkyl chain will lower the polarity of the organic gelator as compared to an organic gelator with shorter alkyl chain.
In accordance with the embodiments of the present disclosure, the organic gelators comprise carbon atoms in the range of C20 to C65.
In accordance with the embodiments of the present disclosure, the organic gelator of the present disclosure has melting point in the range of 60 to 120 °C.
In a second aspect, the present disclosure provides a process for preparing an organic gelator of Formula (I), using hydroxybenzaldehyde of Formula (II), as starting material.

Formula (II)
wherein R1 is selected from C1-C2 alkyl group,
The first step of the process involves alkylation of a hydroxybenzaldehyde of Formula (II), by slow addition of C3-C18 alkyl bromide to a mixture comprising hydroxybenzaldehyde of Formula (II), potassium carbonate and dimethylformamide, under stirring at room temperature, to obtain a slurry comprising dialkoxybenzaldehyde of Formula (III).

wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group
Dialkoxybenzaldehyde of Formula (III) is separated from the slurry.
In the second step of the process, a mixture of dialkoxybenzaldehyde of Formula (III), D-sorbitol and an arylsulfonic acid, in a fluid medium is heated to reflux to obtain a product mixture comprising organic gelator of Formula (I), which is cooled to allow the organic gelator Formula (I) to precipitate and then the product mixture filtered, under reduced pressure, to obtain the organic gelator of Formula (I).

wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group
Typically, the different alkyl chains are introduced to the aromatic backbone to tune the polarity of the organic gelator obtained by acetalization reaction of the dialkoxybenzaldehyde of Formula (III) and D-sorbitol. Introducing a longer alkyl chain to the aromatic backbone of the organic gelator, lowers the polarity of the organic gelator as compared to the organic gelator having a shorter alkyl chain on the aromatic backbone of the organic gelator.
In accordance with the present disclosure the different alkyl chains can be introduced by various reactions/methods.
In accordance with the embodiments of the present disclosure, the molar ratio of C3-C18 alkyl bromide to hydroxybenzaldehyde of Formula (II) is in the range of 0.95:1 to 1.05:1.
In accordance with one embodiment of the present disclosure, the molar ratio of C3-C18 alkyl bromide to hydroxybenzaldehyde of Formula (II) is 1:1.
In accordance with the embodiments of the present disclosure, the molar ratio of potassium carbonate to hydroxybenzaldehyde of Formula (II) is in the range of 3.5:1 to 2.5:1.
In accordance with one embodiment of the present disclosure, the molar ratio of potassium carbonate to hydroxybenzaldehyde of Formula (II) is 3:1.
In accordance with the embodiments of the present disclosure, in step of alkylating, concentration of hydroxybenzaldehyde of Formula (II) is in the range of 15 mmol/L to 25 mmol/L of dimethylformamide.
In accordance with one embodiment of the present disclosure, the in step of alkylating, concentration of hydroxybenzaldehyde of Formula (II) is 20 mmol/L of dimethylformamide.
In accordance with the embodiments of the present disclosure, the step of acetalizing involves an acetalization reaction of the dialkoxybenzaldehyde of Formula (III) and D-sorbitol.
In accordance with the embodiments of the present disclosure, in the step of acetalizing, fluid medium used is a mixture of methanol and cyclohexane in a volume ratio in the range of 2:8 to 4:6 (v/v).
In accordance with the embodiments of the present disclosure, the catalyst is selected from the group consisting of p-toluenesulfonic acid and benzenesulfonic acid.
In accordance with one embodiment of the present disclosure, the catalyst is p-toluenesulfonic acid
In accordance with one embodiment of the present disclosure, in the step of acetalizing, fluid medium used is a mixture of methanol and cyclohexane in a volume ratio of 3:7 (v/v).
Thus, the organic gelators of Formula (Ia-p), are readily-synthesised via an acid-catalysed dehydration-condensation reaction using low cost bulk material, which can be considered for high-tonnage applications, and has high industrial relevance.
The organic gelators of Formula (Ia-p), were purified by simple filtration through Buchner funnel, and washing of the product with the alcohol, and subsequently with water to remove the impurities like reactants, any by-products, catalyst, and solvent.
In a third aspect, the present disclosure provides a process for jellifying an organic liquid, by adding 2.5 to 4 wt% of an organic gelator of Formula (I),

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group,
to 1 ml of an organic liquid, under stirring, to obtain a resultant mixture, which is heated to a temperature in the range of 40 to 70 °C, and then cooled, without disturbance, to room temperature to obtain an organogel.
In accordance with the embodiments of the present disclosure, the organic liquid is at least one selected from the group consisting of ethyl acetate, n-heptane, naphtha, kerosene and diesel.
Clearly, organic gelators of the present disclosure are versatile and responsive, and are selective in nature to the organic liquids for forming gels. Thus, as a gelation system, the organic gelators of the present disclosure have a relatively broad potential and scope, and clearly synthetic derivatisation, can extend this yet further.
Thus, modification of substituents on the aromatic ring of aldehydes used as starting materials for synthesizing the organic gelators of the present disclosure, offers considerable scope for variation. In addition, the free hydroxyl groups of the sorbitol backbone can be readily functionalised to synthesize modified organic gelators. Therefore, it is also possible to generate more complex derivatives using more extended synthetic procedures, and which can have positive impact on gelation of organic liquids.
The present disclosure further provides a process for removing hydrocarbon from an aqueous layer/ oil spillage using the organic gelators described hereinabove.
The organic gelator of the present disclosure may be used to recover hydrocarbon oil from spillage. Further, the organic gelator may be used as clarifiers for polyolefins.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be tested to scale up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
Experimental Details:
Experiment 1:
Step (a): General procedure for the synthesis of 3,4-dialkoxy benzaldehyde of Formula (III):
In a round bottom flask 4-hydroxy-3-alkoxy benzaldehyde (1 mmol), potassium carbonate (3 mmol) and dimethyl farmamide (50 mL) were mixed. n-Alkyl bromide (1 mmol, 2) was added drop wise to the above mixture, under stirring, at room temperature and the reaction mixture was stirred at room temperature for 6 h. The reaction was monitored by thin layer chromatography for completion. After completion of the reaction excess of water was added to the reaction mixture and then extracted with ethyl acetate. The biphasic mixture was allowed to separate into an upper organic layer and a lower aqueous layer. The organic layer was separated, washed with brine, water, dried over sodium sulphite and finally concentrated using rotary evaporator to obtain 3,4-dialkoxy benzaldehyde (III) with an yield in the range of 90-94%, and was directly taken to the next step without any further purification.
Step (a): General procedure for the synthesis of organic gelators of Formula (I):
D-sorbitol (1 mmol), methanol (30 mL) and cyclohexane (70 mL) were mixed in a round bottom flask attached with a dean-stark apparatus. 3,4-Dialkoxy benzaldehyde (2 mmol) and p-toluenesulfonic acid (3 mmol) were added to the mixture, at room temperature. The reaction mixture under stirring, was heated to a temperature of 65 °C, at a rate of 5°C/min. The water liberated during the reaction was removed using dean-stark apparatus. The progress of the reaction was monitored using thin layer chromatography. After completion of the reaction, the reaction mixture was cooled to room temperature and the precipitated solid was separated by filtering through Buchner Funnel under reduced pressure, washed with methanol, followed by washing with water and then recrystallized using appropriate solvent to obtain the organic gelator of Formula (Ia)-(Ip), with a yield in the range of 70-75%. The chemical structures and properties of the organic gelators of the present disclosure are presented in Table-1.

Table 1: Chemical structures and properties of the of the organic gelators of the present disclosure
Compound of Formula Chemical Structure, IUPAC name, Melting point, NMR data
Ia
R1= -CH3, R2= -C3H7
IUPAC Name: 1-[2,6-bis(3-methoxy-4-propoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 120-122 °C.
1H NMR (500 MHz, CDCl3, ppm): 0.90-0.95 (t, 6H, -OCH2CH2CH3),1.60-1.71 (m, 4H, -OCH2CH2CH3), 3.44-3.88 (m, 8H, sugar H), 3.95-4.01 (t, 4H, -OCH2CH2CH3), 4.12 (s, 6H, -OCH3), 4.4-4.45 (t, 1H, -CH2OH), 4.83-4.88 (d, 1H, -CHOH), 5.50 (s, 1H, acetal), 5.55 (s, 1H, acetal), 7.02 (s, 1H, Ar-H), 7.05 (s, 1H, Ar-H), 7.1-7.16 (dd, 2H, Ar-H), 7.35-7.40 (dd, 2H, Ar-H).
Ib
R1= -CH3, R2= -C4H9
IUPAC Name: 1-[2,6-bis(4-butoxy-3-methoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Ic
R1= -CH3, R2= -C7H15
IUPAC Name: 1-[2,6-bis(4-heptyloxy-3-methoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 85-87°C.
1H NMR (500 MHz, CDCl3, ppm): 0.92-0.97 (t, 6H, -O(CH2)6CH3),1.41-1.85 (m, 20H, -O(CH2)6CH3), 3.40-3.78 (m, 8H, sugar H), 3.91-3.98 (t, 4H, -O(CH2)6CH3), 4.10 (s, 6H, -OCH3), 4.35-4.40 (t, 1H, -CH2OH), 4.78-4.84 (d, 1H, -CHOH), 5.38 (s, 1H, acetal), 5.50 (s, 1H, acetal), 6.88 (s, 1H, Ar-H), 6.97 (s, 1H, Ar-H), 7.03-7.09 (dd, 2H, Ar-H), 7.28-7.35 (dd, 2H, Ar-H).
Id
R1= -CH3, R2= -C10H21
IUPAC Name: 1-[2,6-bis(4-decyloxy-3-methoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Ie
R1= -CH3, R2= -C12H25
IUPAC Name: 1-[2,6-bis(4-dodecyloxy-3-methoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

If
R1= -CH3, R2= -C14H29
IUPAC Name: 1-[2,6-bis(3-methoxy-4-tetradecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Ig
R1= -CH3, R2= -C16H33
IUPAC Name: 1-[2,6-bis(3-methoxy-4-hexadecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 62-64°C.
1H NMR (500 MHz, CDCl3, ppm): 0.88-0.93 (t, 6H, -O(CH2)15CH3),1.15-1.75 (m, 56H, -O(CH2)15CH3), 3.32-3.55 (m, 8H, sugar H), 3.72-3.82 (t, 4H, -O(CH2)15CH3), 3.87 (s, 6H, -OCH3), 4.15-4.22 (t, 1H, -CH2OH), 4.61-4.70 (d, 1H, -CHOH), 5.20 (s, 1H, acetal), 5.37 (s, 1H, acetal), 6.68 (s, 1H, Ar-H), 6.74 (s,1H, Ar-H), 6.81-6.92 (dd, 2H, Ar-H), 7.11-7.22 (dd, 2H, Ar-H).
Ih
R1= -CH3, R2= -C18H37
IUPAC Name: 1-[2,6-bis(3-methoxy-4-octadecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Ii
R1= -C2H5, R2= -C3H7
IUPAC Name: 1-[2,6-bis(3-ethoxy-4-propoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 115-117 °C.
1H NMR (500 MHz, CDCl3, ppm): 0.89-0.94 (t, 6H, -OCH2CH2CH3),1.60-1.67 (m, 4H, -OCH2CH2CH3), 1.84-1.88 (t, 6H, -OCH2CH3), 3.41-3.85 (m, 8H, sugar H), 3.97-4.02 (t, 4H, -OCH2CH2CH3), 4.08-4.15 (m, 4H, -OCH2CH3), 4.37-4.41 (t, 1H, -CH2OH), 4.80-4.85 (d, 1H, -CHOH), 5.43 (s, 1H, acetal), 5.51 (s, 1H, acetal), 6.98 (s, 1H, Ar-H), 7.01 (s, 1H, Ar-H), 7.07-7.14 (dd, 2H, Ar-H), 7.30-7.35 (dd, 2H, Ar-H).
Ij
R1= -C2H5, R2= -C4H9
IUPAC Name: 1-[2,6-bis(4-butoxy-3-ethoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Ik
R1= -C2H5, R2= -C7H15
IUPAC Name: 1-[2,6-bis(3-ethoxy-4-heptyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 82-84°C.
1H NMR (500 MHz, CDCl3, ppm): 0.86-0.91 (t, 6H, -O(CH2)6CH3),1.52.-1.62 (m, 20H, -O(CH2)6CH3), 1.80-1.85 (t, 6H, -OCH2CH3), 3.35-3.80 (m, 8H, sugar H), 3.90-3.97 (t, 4H, -O(CH2)6CH3), 4.01-4.10 (m, 4H, -OCH2CH3), 4.31-4.35 (t, 1H, -CH2OH), 4.72-4.78 (d, 1H, -CHOH), 5.37 (s, 1H, acetal), 5.46 (s, 1H, acetal), 6.82 (s, 1H, Ar-H), 6.95 (s, 1H, Ar-H), 6.99-7.01 (dd, 2H, Ar-H), 7.25-7.33 (dd, 2H, Ar-H).
Il R1= R1= -C2H5, R2= -C10H21
IUPAC Name: 1-[2,6-bis(4-decyloxy-3-ethoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Im
R1= -C2H5, R2= -C12H25
IUPAC Name: 1-[2,6-bis(4-dodecyloxy-3-ethoxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

In
R1= -C2H5, R2= -C14H29
IUPAC Name: 1-[2,6-bis(3-ethoxy-4-tetradecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
Io
R1= -C2H5, R2= -C16H33

IUPAC Name: 1-[2,6-bis(3-ethoxy-4-hexadecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
MP: 60-62°C.
1H NMR (500 MHz, CDCl3, ppm): 0.82-0.88 (t, 6H, -O(CH2)15CH3),1.11.-1.72 (m, 56H, -O(CH2)15CH3), 3.30-3.50 (t, 6H, -OCH2CH3), 3.28-3.3.51 (m, 8H, sugar H), 3.67-3.74 (t, 4H, -O(CH2)15CH3), 3.81-3.92 (m, 4H, -OCH2CH3), 4.11-4.20 (t, 1H, -CH2OH), 4.59-4.70 (d, 1H, -CHOH), 5.17 (s, 1H, acetal), 5.30 (s, 1H, acetal), 6.62 (s, 1H, Ar-H), 7.01 (s, 1H, Ar-H), 6.75-6.84 (dd, 2H, Ar-H), 7.05-7.15 (dd, 2H, Ar-H).
Ip
R1= -C2H5, R2= -C18H37
IUPAC Name: 1-[2,6-bis(3-ethoxy-4-octadecyloxyphenyl)tetrahydro-2H,6H-[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Experiment 2: Gelation studies of the organic gelators of the present disclosure with different solvents/petroleum oils:
Each of the organic gelators (Ia-p) were independently added to 1 mL of solvent/petroleum oil in a glass test tube. The mixture was warmed gently and cooled slowly to room temperature without disturbance. After some time, the mixture was observed for the formation of gel. The minimum concentration of the gelator (MGC) required to form the gel was calculated by the slow addition of the known amount of gelator to the solvent (1 mL) and repeating the above process of heating and cooling. Gelation study was carried out with different solvents like ethyl acetate, n-heptane and with petroleum oils like naphtha, kerosene and diesel. Results are tabulated in the Table 2.
Table 2: Gelation Behaviour of the organic gelators with different solvent/oil media
Organic Gelators Organic Liquid
Ethyl Acetate n-Heptane
Naphtha Kerosene Diesel
G/P/PS MGC,
%wt/vol G/P/PS MGC,
%wt/vol G/P/PS MGC,
%wt/vol G/P/PS MGC,
%wt/vol G/P/PS MGC,
%wt/vol
Ia G 2.95 P - P - P - P -
Ii G 3.05 P - P - P - P -
Ib G 3.25 P - P - P - P -
Ij G 3.30 P - P - P - P -
Ic P - G 2.56 G 2.55 G 2.67 G 2.88
Ik P - G 2.50 G 2.47 G 2.75 G 2.78
Id P - G 2.85 G 2.70 G 2.70 G 2.35
Il P - G 2.90 G 2.85 G 2.63 G 2.40
Ie P - G 3.00 G 2.90 G 2.81 G 2.20
Im P - G 3.15 G 2.92 G 2.88 G 2.30
If P - G 3.32 G 2.95 G 2.91 G 2.56
In P - G 3.38 G 2.95 G 2.93 G 2.60
Ig P - PS - G 2.98 G 2.95 G 3.56
Io P - PS - G 3.00 G 2.98 G 3.85
Ih P - P - G 3.06 P - PS -
Io P - P - G 3.10 P - PS -
Note: Where: G represents Gelation, P represents Precipitate, PS represents partial solution, MGC represents minimum concentration of gelator required to form gel % wt/vol
It is clearly observed from Table-2 that the Organic Gelators Ia, Ib, Ii and Ij, wherein R1 = -CH3 or -C2H5, and R2 = C3H7 or C4H9, selectively form gels with mid-polar solvents like ethyl acetate. However, these Organic Gelators do not show any gelation behaviour with petroleum oils like naphtha, kerosene and diesel.
It is clearly observed from Table-2 that the Organic Gelators Ic, Id, Ie, If, Ik, Il, Im and In, wherein R1 = -CH3 or -C2H5, and R2 = -C7H15, -C10H21, -C12H25 and -C14H29, selectively form gel with n-heptane, naphtha, kerosene and diesel. However, these Organic Gelators do not show any gelation behaviour with ethyl acetate.
It is clearly observed from Table-2 that the Organic Gelators Ig and Io, wherein R1 = -CH3 or -C2H5 and R2 = C16H33, selectively form gel with naphtha, kerosene and diesel. However, these Organic Gelators do not show any gelation behaviour with n-heptane and ethyl acetate.
It is clearly observed from Table-2 that the Organic Gelators Ih and Ip, wherein R1 = -CH3 or -C2H5 and R2 = C18H37, selectively form gel with naphtha. However, these Organic Gelators do not show any gelation behaviour with other organic liquids (ethyl acetate, n-heptane, kerosene and Diesel).
The organic gelators of the present disclosure are promising materials for the petroleum oil recovery from spillage.
The MGC values vary for compounds with different substitutions and for different petroleum oils.
Polarity of the new gelators can be easily tuned by varying the alkyl chain length of the aromatic backbone.
Since the composition of petroleum oils are varying with respect to crude oil, accordingly MGC value of the gelators may also be varied from sample to sample. The best suitable gelator with desired alkyl group substitution and with low MGC value can be taken for oil spillage application.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of organic gelators for removal of oil spills.
The embodiments as described herein above, and various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
The foregoing description of specific embodiments so fully reveal the general nature of the embodiments herein, that others can, by applying current knowledge, readily modify and/or adapt for various applications of such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Further, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
Having described and illustrated the principles of the present disclosure with reference to the described embodiments, it will be recognized that the described embodiments can be modified in arrangement and detail without departing from the scope of such principles.
While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. An organic gelator of Formula (I):

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group.
2. The organic gelator as claimed in claim 1, wherein said C1-C2 alkyl group is selected from methyl and ethyl, and said C3-C18 alkyl group is selected from n-propyl, n-butyl, n-heptyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl and n-octadecyl.
3. The organic gelator as claimed in claim 1, wherein said organic gelator has melting point in the range of 60 to 120 °C.
4. The organic gelator as claimed in claim 1, wherein said organic gelator is selected from:






5. A process for the preparation of an organic gelator of Formula (I),

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group,
said process comprising the following steps:
(a) alkylating hydroxybenzaldehyde of Formula (II),

Formula (II)
wherein R1 is selected from C1-C2 alkyl group,
by slowly adding C3-C18 alkyl bromide to a mixture comprising said hydroxybenzaldehyde of Formula (II), potassium carbonate and dimethylformamide, under stirring at room temperature, to obtain a slurry comprising dialkoxybenzaldehyde of Formula (III),

Formula (III)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group;
(b) separating said dialkoxybenzaldehyde of Formula (III) from said slurry;
(c) acetalizing said separated dialkoxybenzaldehyde of Formula (III) by heating said dialkoxybenzaldehyde of Formula (III), with a mixture of D-sorbitol, a catalyst and at least one fluid medium, at reflux to obtain a product mixture comprising organic gelator of Formula (I).
(d) cooling said product mixture to allow said organic gelator Formula (I) to precipitate.
(e) filtering said precipitated organic gelator of Formula (I) from said product mixture, under reduced pressure, to obtain the organic gelator of Formula (I).
6. The process as claimed in claim 5, wherein the molar ratio of C3-C18 alkyl bromide to hydroxybenzaldehyde of Formula (II) is in the range of 0.95:1 to 1.05:1
7. The process as claimed in claim 5, wherein the molar ratio of potassium carbonate to hydroxybenzaldehyde of Formula (II) is in the range of 3.5:1 to 2.5:1.
8. The process as claimed in claim 5, wherein in step (a) of alkylating, the concentration of hydroxybenzaldehyde of Formula (II) is in the range of 15 mmol/L to 25 mmol/L of dimethylformamide.
9. The process as claimed in claim 5, wherein said catalyst is selected from the group consisting of p-toluenesulfonic acid and benzenesulfonic acid.
10. The process as claimed in claim 5, wherein said fluid medium is selected from the group consisting of methanol, cyclohexane and mixture thereof.
11. The process as claimed in claim 5, wherein said fluid medium is a mixture of methanol and cyclohexane in a volume ratio in the range of 2:8 to 4:6 (v/v).
12. The process as claimed in claims 5, wherein step (b) of separating comprises:
i) adding water to the slurry, followed by extracting with ethyl acetate to obtain a biphasic mixture comprising an upper organic layer and a lower aqueous layer;
ii) separating the organic layer from said biphasic mixture, washing with brine and water;
iii) drying said washed organic layer over sodium sulphate; and
iv) concentrating said dried organic layer to obtain dialkoxybenzaldehyde of Formula (III), with an yield in the range of 90-94%.
13. A process for jellifying an organic liquid to obtain an organogel, said process comprising the following steps:
i) adding 2.5 to 4 wt% of an organic gelator of Formula (I),

Formula (I)
wherein R1 is selected from C1-C2 alkyl group, and R2 is selected from C3-C18 alkyl group,
to 96 to 97.5 wt% of an organic liquid, under stirring, to obtain a resultant mixture; wherein the weight percentages of the components are with respect to the total weight of the organogel;
ii) heating said resultant mixture, under stirring, to a temperature in the range of 40 to 70 °C; and
iii) cooling said heated mixture, without disturbance, to room temperature to obtain an organogel.

14. The process as claimed in claim 13, wherein said organic liquid is at least one selected from the group consisting of ethyl acetate, n-heptane, naphtha, kerosene and diesel.