DESC:FIELD
The present disclosure relates to a process for the preparation of disulfide compounds. Particularly, the present disclosure relates to a process for the preparation of dialkyl disulfide compounds and diaryl disulfide compounds.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
The disulfide compounds are important intermediates used in the production of various compounds such as ethiprole.
Ethiprole is a non-systemic phenyl-pyrazole insecticide that is effective against a wide range of insects. In insects, Ethiprole acts on ?-aminobutyric acid-dependent neurotransmission present in the central nervous system. It is effective against a broad spectrum of insects with chewing and sucking mouthparts that tend to damage the plants. Ethiprole has a high level of selective toxicity, and thus avoids cross-resistance.
Conventional methods for the preparation of dialkyl disulfide compounds and diaryl disulfide compounds involve the use of sulfur transfer agents, bases and require high temperatures to carry out the reaction. Moreover, the conventional processes are associated with the drawbacks such as impurities in the product that requires further purification and are not economical. If not purified, the impurities in the final product may affect the efficacy, safety, and stability of the final product. The yield/productivity of dialkyl disulfide and diaryl disulfide compounds obtained from the known processes is considerably low.
Therefore, there is felt a need to provide a process for the preparation of dialkyl disulfide compounds and diaryl disulfide compounds that mitigates the aforestated drawbacks or at least provide an alternative solution.
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 a process for the preparation of disulfide compounds.
Yet another object of the present disclosure is to provide a process for the preparation of disulfide compounds with comparatively better purity and yield.
Still another object of the present disclosure is to provide a simple and cost-effective process for the preparation of disulfide compounds.
Yet another object of the present disclosure is to provide a process for the preparation of dialkyl disulfide compounds and diaryl disulfide compounds.
Another object of the present disclosure is to provide an environment-friendly and commercially scalable process for the preparation of disulfide compounds.
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 a process for the preparation of disulfide compounds. The process comprises reacting sodium sulfide with sulfur powder in a predetermined weight ratio in a first fluid medium at a first predetermined temperature for a first predetermined time period to obtain sodium disulfide solution. The sodium disulfide solution is cooled to a temperature in the range of 20°C to 40°C to obtain a cooled sodium disulfide solution. The cooled sodium disulfide solution is mixed with a second fluid medium followed by the addition of a catalyst to obtain a first mixture. To the first mixture, a predetermined amount of a compound selected from an alkyl halide and aryl halide is slowly added at a temperature in the range of 20°C to 40°C over a second predetermined time period to obtain a second mixture. The second mixture is maintained at a temperature in the range of 20°C to 40°C for a third predetermined time period under stirring to obtain a product mixture comprising disulfide compounds.
In accordance with the present disclosure, the first fluid medium is water.
In accordance with the present disclosure, the predetermined weight ratio of sodium sulphide to sulfur powder is in the range of 5:1 to 15:1.
In accordance with the present disclosure, the first predetermined temperature is in the range of 35°C to 70°C.
In accordance with the present disclosure, the first predetermined time period and third predetermined time period are independently in the range of 1 hour to 4 hours.
In accordance with the present disclosure, the second fluid medium is selected from the group consisting of toluene, cyclohexane, n-hexane, n-heptane and cycloheptane.
In accordance with the present disclosure, the catalyst is selected from the group consisting of tetrabutylammonium bromide (TBAB), tetrabutyl ammonium chloride (TBACl), triethyl benzyl ammonium chloride (TEBACl) and tetramethyl ammonium chloride (TMACl).
In accordance with the present disclosure, the alkyl halide is selected from the group consisting of ethyl chloride, methyl chloride, butyl bromide, ethyl bromide, ethyl iodide and isopropyl bromide.
In accordance with the present disclosure the aryl halide is selected from the group consisting of benzyl chloride and benzyl bromide.
DETAILED DESCRIPTION
The present disclosure relates to a process for the preparation of disulfide compounds.
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.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Conventional methods for the preparation of dialkyl disulfide compounds and diaryl disulfide compounds involve the use of sulfur transfer agents, bases and require high temperatures to carry out the reaction. Moreover, the conventional processes are associated with the drawbacks such as impurities in the product that requires further purification and are not economical. If not purified, the impurities in the final product may affect the efficacy, safety, and stability of the final product. The yield/productivity of dialkyl disulfide and diaryl disulfide compounds obtained from the known processes is considerably low.
The present disclosure provides an improved process for the preparation of disulfide compounds.
The process of the present disclosure is simple, environment friendly, economical, results in improved yield and higher purity of disulfide compounds, and is commercially scalable.
In an aspect, the present disclosure provides a process for preparing
disulfide compounds.
The process for preparing disulfide compounds comprises the following steps:
i. reacting sodium sulfide with sulfur powder in a predetermined weight ratio in a first fluid medium at a first predetermined temperature for a first predetermined time period to obtain sodium disulfide solution;
ii. cooling the sodium disulfide solution to a temperature in the range of 20°C to 40°C to obtain a cooled sodium disulfide solution;
iii. mixing the cooled sodium disulfide solution with a second fluid medium followed by adding a catalyst to obtain a first mixture;
iv. slowly, adding a compound selected from alkyl halide and aryl halide to the first mixture at a temperature in the range of 20°C to 40°C over a second predetermined time period to obtain a second mixture; and
v. maintaining the second mixture at a temperature in the range of 20°C to 40°C for a third predetermined time period under stirring to obtain a product mixture comprising disulfide compounds.

The process for the preparation of disulfide compounds in accordance with the present disclosure is given in detail below.
In a first step, sodium sulfide is reacted with sulfur powder in a predetermined weight ratio in a first fluid medium at a first predetermined temperature for a first predetermined time period to obtain a sodium disulfide solution.
The predetermined weight ratio of sodium sulfide to sulfur powder is in the range of 5:1 to 15:1. In an exemplary embodiment, the predetermined weight ratio of sodium sulphide to sulfur powder is 8:1.
The predetermined weight ratio of sodium sulfide to sulfur powder is important to get the desired yield of product.
The first fluid medium is water.
The use of water as a solvent makes the process of the present disclosure economical.
The first predetermined temperature is in the range of 35°C to 70°C. In an exemplary embodiment, the first predetermined temperature is 50°C.
The first predetermined time period is in the range of 1 hour to 4 hours. In an exemplary embodiment, the first predetermined time period is 2 hours.
In a second step, sodium disulfide solution is cooled to a temperature in the range of 20°C to 40°C to obtain a cooled sodium disulfide solution. In an exemplary embodiment, the sodium disulfide solution is cooled to a temperature of 30°C.
In a third step, the cooled sodium disulfide solution is mixed with a second fluid medium followed by the addition of a catalyst to obtain a first mixture.
The second fluid medium is selected from the group consisting of toluene, cyclohexane, n-hexane, n-heptane and cycloheptane. In an exemplary embodiment, the second fluid medium is toluene. In another exemplary embodiment, the second fluid medium is cyclohexane.
The catalyst is selected from tetrabutylammonium bromide (TBAB), tetrabutyl ammonium chloride (TBACl), triethyl benzyl ammonium chloride (TEBACl), tetramethyl ammonium chloride (TMACl). In an exemplary embodiment, the catalyst is tetrabutylammonium bromide (TBAB).
In a fourth step, a compound selected from an alkyl halide and aryl halide is slowly added to the first mixture at a temperature in the range of 20°C to 40°C over a second predetermined time period to obtain a second mixture.
The predetermined weight ratio of the compound selected from alkyl halide and aryl halide to the catalyst is in the range of 15:1 to 65:1. In an exemplary embodiment, the predetermined weight ratio of the compound selected from alkyl halide and aryl halide to the catalyst is 25:1. In another exemplary embodiment, the predetermined weight ratio of the compound selected from alkyl halide and aryl halide to the catalyst is 21:1. In yet another exemplary embodiment, the predetermined weight ratio of the compound selected from alkyl halide and aryl halide to the catalyst is 57:1. In still another exemplary embodiment, the predetermined weight ratio of the compound selected from alkyl halide and aryl halide to the catalyst is 53:1.
In accordance with the present disclosure, the alkyl halide is selected from the group consisting of ethyl chloride, methyl chloride, butyl bromide and isopropyl bromide. In an exemplary embodiment, the alkyl halide is ethyl chloride. In another exemplary embodiment, the alkyl halide is methyl chloride. In still another exemplary embodiment, the alkyl halide is butyl bromide. In yet another exemplary embodiment, the alkyl halide is isopropyl bromide.
In accordance with the present disclosure, the aryl halide is selected from the group consisting of benzyl chloride and benzyl bromide. In an exemplary embodiment the aryl halide is benzyl chloride.
The second predetermined time period is in the range of 2 hours to 7 hours. In an exemplary embodiment, the second predetermined time period is 5 hours.
In a fifth step, the second mixture is maintained at a temperature in the range of 20°C to 40°C for a third predetermined time period under stirring to obtain a product mixture comprising dialkyl/diaryl disulfide compound. In an exemplary embodiment, the second mixture is maintained at a temperature of 30°C.
In accordance with the present disclosure, the third predetermined time period is in the range of 1 hour to 4 hours. In an exemplary embodiment, the third predetermined time period is 2 hours.
In accordance with the present disclosure, the reaction is monitored by gas liquid chromatograghy (GLC). The product mixture comprising dialkyl disulfide compound or diaryl disulfide compound is separated to obtain a separated first organic layer and a separated first aqueous layer. The so obtained separated first aqueous layer is mixed with the second fluid medium, followed by separation to obtain a second organic layer and a second aqueous layer. The separated first organic layer and the separated second organic layer are mixed, followed by washing with water. The organic layer is separated from water layer and the separated organic layer is distilled to remove the second fluid medium to obtain the disulfide compound.
A schematic representation for the preparation of dialkyl disulfide compound is given as scheme A, as one of the exemplary embodiments:

In an embodiment of the present disclosure, the disulfide compounds have a purity of >98%.
The process of the present disclosure avoids the use of expensive sulfur transfer agents, bases and proceeds under mild reaction conditions thereby making the process simple and environment friendly.
The present disclosure provides a simple and economic process for the preparation of disulfide compounds with a comparatively higher yield and better purity.
The foregoing description of the embodiments has been provided for purposes of illustration and is 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 scaled up to industrial/commercial scale and the results obtained can be extrapolated to the industrial scale.
EXPERIMENTAL DETAILS
EXAMPLE 1:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50 °C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of toluene followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 129 gm of ethyl chloride gas was slowly passed over a period of 5 hours at 30°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising diethyl disulfide compound in an organic layer. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, diethyl disulfide compound present in the organic layer (toluene) was separated from the product mixture to obtain a separated first organic layer and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of toluene wherein a second organic layer (toluene) was separated from the second aqueous layer. The separated second organic layer was mixed with the separated first organic layer, followed by washing with water. The organic layer was separated from the water layer and the separated organic layer was distilled to remove toluene to obtain diethyl disulfide.
The purity of diethyl disulphide was 98.9% by GLC and the yield was 113 gm.
EXAMPLE 2:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50°C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of cyclohexane followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 129 gm of ethyl chloride gas was slowly passed over a period of 5 hours at 30°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising diethyl disulfide compound in an organic layer. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, diethyl disulfide compound present in the organic layer was separated from the product mixture to obtain a separated first organic layer (cyclohexane) and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of cyclohexane wherein a second organic layer (cyclohexane) was separated from a second aqueous layer. The separated first organic layer and the separated second organic layer were mixed, followed by washing with water. The organic layer was separated from water layer and the separated organic layer was distilled to remove cyclohexane to obtain diethyl disulfide.
The purity of diethyl disulphide was 99% by GLC and the yield was 112 gm.
EXAMPLE 3:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50°C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of toluene followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 106 gm of methyl chloride gas was slowly passed over a period of 5 hours at 40°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising dimethyl disulfide compound. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, dimethyl disulfide compound present in the organic layer was separated from the product mixture to obtain a separated first organic layer (toluene) and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of toluene wherein a second organic layer (toluene) was separated from a second aqueous layer. The separated first organic layer and the separated second organic layer were mixed, followed by washing with water. The organic layer was separated from water layer and the separated organic layer was distilled to remove toluene to obtain dimethyl disulfide.
The purity of dimethyl disulfide was 98.5% by GLC and the yield was 85 gm.
EXAMPLE 4:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50°C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of cyclohexane followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 288 gm of butyl bromide liquid was slowly passed over a period of 5 hours at 35°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising dibutyl disulfide compound in an organic layer. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, dibutyl disulfide compound present in the organic layer was separated from the product mixture to obtain a separated first organic layer (cyclohexane) and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of cyclohexane wherein a second organic layer (cyclohexane) was separated from a second aqueous layer. The separated second organic layer was mixed with the separated first organic layer followed by washing with water. The organic layer was separated from water layer and the organic layer was distilled to remove cyclohexane to obtain dibutyl disulfide.
The purity of dibutyl disulfide was 98.0% by GLC and the yield was 152 gm.
EXAMPLE 5:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50°C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of cyclohexane followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 288 gm of isopropyl bromide liquid was slowly passed over a period of 5 hours at 30°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising di-isopropyl disulfide compound in an organic layer. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, di-isopropyl disulfide compound present in the organic layer was separated to obtain a separated first organic layer (cyclohexane) and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of cyclohexane wherein a second organic layer (cyclohexane) was separated from a second aqueous layer. The separated second organic layer was mixed with the separated first organic layer, followed by washing with water. The organic layer was separated from the water layer and the separated organic layer was distilled to remove cyclohexane to obtain di-isopropyl disulfide.
The purity of di-isopropyl disulfide was 98.5% by GLC and the yield was 135 gm.
EXAMPLE 6:
265 gm of sodium sulfide (59% purity) was charged into a reactor containing 500 ml of water followed by adding 32 gm of sulfur powder under stirring to obtain a mixture. The mixture was heated to 50 °C for 2 hours to obtain a sodium disulfide solution.
The so obtained sodium disulfide solution was cooled to a temperature of 30°C to obtain a cooled sodium disulfide solution. The so obtained cooled sodium disulfide solution was mixed with 300 ml of toluene followed by adding 5 gm of Tetrabutyl ammonium bromide catalyst to obtain a first mixture. To the first mixture, 265 gm of benzyl chloride liquid was slowly passed over a period of 5 hours at 40°C to obtain a second mixture. The so obtained second mixture was further stirred at 30°C for 2 hours to obtain a product mixture comprising dibenzyl disulfide compound in organic layer. The reaction was monitored by gas liquid chromatography (GLC) of the organic layer.
After complete conversion, dibenzyl disulfide compound present in the organic layer (toluene) was separated from the product mixture to obtain a separated first organic layer (toluene) and a separated first aqueous layer. The so obtained separated first aqueous layer was further mixed with 100 ml of toluene wherein a second organic layer (toluene) was separated from the second aqueous layer. The separated second organic layer was mixed with the separated first organic layer followed by washing with water. The organic layer was separated from water layer and the separated organic layer was distilled to remove toluene to obtain dibenzyl disulfide.
The purity of dibenzyl disulfide was 98.5% by GLC and the yield was 85 gm.
TECHNICAL ADVANCEMENT
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a process for the preparation of disulfide compounds that
• uses water as a solvent, hence economical;
• avoids the use of sulfur transfer agents;
• avoids the use of bases;
• proceeds under mild reaction conditions;
• is simple and environment friendly; and
• provides disulfide compounds having comparatively high purity and high yield.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the 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 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.
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 invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure 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. A process for preparing disulfide compounds, said process comprising the following steps:
i. reacting sodium sulfide with sulfur powder in a predetermined weight ratio in a first fluid medium at a first predetermined temperature for a first predetermined time period to obtain sodium disulfide solution;
ii. cooling the sodium disulphide solution to a temperature in the range of 20°C to 40°C to obtain a cooled sodium disulfide solution;
iii. mixing said cooled sodium disulfide solution with a second fluid medium followed by adding a catalyst to obtain a first mixture;
iv. slowly, adding a compound selected from alkyl halide and aryl halide to said first mixture at a temperature in the range of 20°C to 40°C over a second predetermined time period to obtain a second mixture; and
v. maintaining said second mixture at a temperature in the range of 20°C to 40°C for a third predetermined time period under stirring to obtain a product mixture comprising disulfide compounds.
2. The process as claimed in claim 1, wherein said first fluid medium is water.

3. The process as claimed in claim 1, wherein said predetermined weight ratio of sodium sulfide to sulfur powder is in the range of 5:1 to 15:1.

4. The process as claimed in claim 1, wherein said first predetermined temperature is in the range of 35°C to 70°C.

5. The process as claimed in claim 1, wherein said first predetermined time period and said third predetermined time period are independently in the range of 1 hour to 4 hours.

6. The process as claimed in claim 1, wherein said second fluid medium is selected from the group consisting of toluene, cyclohexane, n-hexane, n-heptane and cycloheptane.

7. The process as claimed in claim 1, wherein said catalyst is selected from the group consisting of tetrabutylammonium bromide (TBAB), tetrabutyl ammonium chloride (TBACl), triethyl benzyl ammonium chloride (TEBACl), tetramethyl ammonium chloride (TMACl).

8. The process as claimed in claim 1, wherein a weight ratio of said compound selected from alkyl halide and aryl halide to said catalyst is in the range of 15:1 to 65:1.

9. The process as claimed in claim 1, wherein said alkyl halide is selected from the group consisting of ethyl chloride, ethyl bromide, ethyl iodide, methyl chloride, butyl bromide and isopropyl bromide.

10. The process as claimed in claim 1, wherein said aryl halide is selected from the group consisting of benzyl chloride and benzyl bromide.

11. The process as claimed in claim 1, wherein said second predetermined time period is in the range of 2 hours to 7 hours.

Dated this 14th day of August, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant
TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI