Description:FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(see sections 10 & rule 13)
1. TITLE OF THE INVENTION
A PROCESS FOR PREPARING BIS(2,4-DI-TERT-BUTYLPHENYL) HYDROGEN PHOSPHATE-D4
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
CLEARSYNTH LABS LIMITED Indian
17th Floor, Lotus Nilkamal Business Park, New Link Road, Andheri [West], Mumbai - 400053, Maharashtra, 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

FIELD OF INVENTION
The present invention relates to a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4. Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄ provides greater stability, enhanced analytical capabilities, and valuable mechanistic insights compared to the non-deuterated version which makes it particularly useful in chemical, pharmaceutical, and material science research, where deuterium labelling plays a crucial role in reaction studies and isotopic tracing.

BACKGROUND OF INVENTION
Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄ is a deuterated derivative of bis(2,4-di-tert-butylphenyl) hydrogen phosphate represented by

It is commonly used in catalysis, extraction, and material applications. The incorporation of deuterium enhances its utility in mechanistic studies, isotopic labelling experiments, and spectroscopic analyses such as NMR, where deuterium substitution helps reduce background interference and provides insights into reaction dynamics.
Bis(2,4-di-tert-butylphenyl) hydrogen phosphate is an organophosphate compound widely used as an acid catalyst in organic transformations such as esterification and transesterifications. It is also employed in extraction and separation processes due to its high lipophilicity and in material science for modifying polymer properties.
The synthesis of this compound involves the reaction of 2,4-di-tert-butylphenol with a phosphorylating agent to introduce the hydrogen phosphate functional group.
The deuterated derivative, Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄, offers several advantages over its non-deuterated counterpart due to the incorporation of deuterium in the phosphate group. These benefits span across stability, analytical applications, and mechanistic studies. The presence of deuterium in the phosphate group results in a kinetic isotope effect (KIE), which slows down hydrolysis and degradation reactions. This leads to improved chemical stability, making the compound more suitable for long-term storage and applications in moisture-sensitive environments.
Deuterium incorporation can slightly alter the thermal properties, potentially improving the compound’s resistance to decomposition at elevated temperatures. The replacement of hydrogen with deuterium in the phosphate group eliminates proton-related interference in ¹H NMR spectra. This makes it easier to analyse complex systems without overlapping signals.
The deuterium-labelled compound allows for isotope tracing in mass spectrometric studies, improving the differentiation of reaction pathways and decomposition products. The deuterated version enables researchers to study reaction mechanisms and rate-determining steps by comparing reaction rates with its non-deuterated counterpart. The d₄-labelled phosphate can be used as a molecular probe in membrane transport, enzyme interactions, and catalytic pathways to track molecular transformations and reaction intermediates. Due to enhanced stability, the deuterated compound may show better performance as a lubricant additive or polymer modifier, offering prolonged efficacy compared to its non-deuterated counterpart.
Therefore, while considering above mentioned advantages of deuterated compound Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄, there is a need to prepare Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄ compound.
The present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d₄ which provides greater stability, enhanced analytical capabilities, and valuable mechanistic insights compared to the non-deuterated version. These advantages make it particularly useful in chemical, pharmaceutical, and material science research, where deuterium labelling plays a crucial role in reaction studies and isotopic tracing.

OBJECTS OF THE INVENTION
One of the objects of the present invention is to provide a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Another object of the present invention is to characterize the prepared Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Another object of the present invention is to provide a process which involves minimize use of hazardous substances, reduce waste, conserve energy includes using safer solvents, catalysts, and reaction conditions.
Yet another object of the present invention is to provide a shorter synthetic route which reduces the number of steps, minimizing the use of reagents and reducing the risk of side reactions.

SUMMARY OF THE INVENTION
Main aspect of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, the process comprising:
a) contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in a solvent to obtain a crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and
b) purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained from step (a) in a solvent or mixture of solvent to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Another aspect of the present invention provides a process for purifying the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, the process comprising:
i. dissolving the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in a solvent to obtain a mixture;
ii. cooling the mixture -5oC to 5oC and adjusting a pH in the range of 7 to 9 by using a base to obtain a reaction mixture;
iii. stirring the reaction mixture for a period in the range of 8 hrs to 14 hrs;
iv. extracting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 with a solvent and evaporating the solvent to obtain Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and
v. eluting Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 through silica gel column with a solvent to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.

BRIEF DESCRIPTION OF FIGURES OF THE PRESENT INVENTION
Figure 1 & 2 shows 1H NMR of Bis(2,4-di-tert-butylphenyl) hydrogen phosphate.
Figure 2 depicts 1H NMR of pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Figure 3 shows Mass of pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.

DETAILED DESCRIPTION OF THE INVENTION
In the present invention, different terms are used to describe the invention in the specification. The definitions of the terms are provided below.
The term ‘crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4’ used herein refers to Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4’ having byproducts from the reaction, unreacted starting materials, solvents, and other contaminants. The crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained is having purity in the range of 90% to 99% by HPLC, preferably 90% to 98% by HPLC.
The term ‘pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4’ used herein refers to a substance (Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4’) that consists of only one type of molecule or ion. It has a fixed chemical composition and distinct, consistent properties. Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 which is free from impurities or other substances such as but is not limited to salt, byproduct etc. The pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 is having purity in the range of 95% to 99.99% by High-Performance Liquid Chromatography (HPLC), preferably 98% to 99.99% by HPLC.
The term ‘mixture’ used herein refers to a solution of crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained by dissolving the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in solvent.
The term ‘reaction mixture’ used herein means solution obtained by basifying using a base at a pH in the range of 7 to 9, preferably 8.
The term ‘solvent’ used herein refers to a substance that can dissolve another substance, or in which another substance is dissolved, forming a solution. The solvent used in the present invention can be polar or nonpolar solvent. The solvent includes such as but not limit to alcohols, ethers, ketones, acids, esters, acetonitrile (ACN), hydrocarbon solvent, halogenated solvent(s) and/or deuterated form of alcohols, ethers, ketones, acids, esters, and/or deuterated halogenated solvent(s).
One of the embodiments of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4,

the process comprising:
a) contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in a solvent to obtain a crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and
b) purifying the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained from step (a) in a solvent or a solvent mixture to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein said preparation is presented in following scheme.
Scheme:

Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the reagent is selected from Chlorine gas (Cl₂), Sodium hypochlorite (NaOCl), Calcium hypochlorite (Ca(OCl)₂), Potassium hypochlorite (KOCl), Chlorine dioxide (ClO₂), Hydrochloric acid (HCl), Phosphorus pentachloride (PCl₅) and Phosphorus trichloride (PCl₃), Phosphorus oxychloride (POCl₃), Thionyl chloride (SOCl₂) and combinations thereof.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the reagent is Phosphorus oxychloride (POCl₃).
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the base is organic and/or inorganic base.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein organic base is selected from sodium alkoxide, potassium alkoxide, butyl lithium, triethyl amine (TEA), di-isopropyl ethylamine, pyridine, piperidine, quinoline, 4-dimethylaminopyridine or an organic amine and combinations thereof.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein organic base is triethyl amine (TEA) and pyridine.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein inorganic base is selected from sodium hydroxide, potassium hydroxide, strontium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, cesium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium carbonate, sodium carbonate, strontium carbonate, cesium carbonate, sodium sulfide, sodium hydride and combinations thereof.
Another preferred embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein inorganic base is sodium hydroxide.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the solvent is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, tert-butanol, n-pentyl alcohol, isoamyl alcohol, ethylene glycol, propylene glycol, glycerol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetonitrile, dioxane, N-methyl pyrrolidone, methylene chloride, chloroform, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or ethylene glycol monomethyl ether, toluene, xylene, cumene, cymene, N-methylpyrrolidone and combinations thereof.
Another preferred embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the solvent used for purification is water, dichloromethane, toluene and combinations thereof.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in an inert solvent is carried out a time period in the range of 30mins to 18 hrs.
Another preferred embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in an inert solvent is carried out at RT for 18 hrs and at reflux temperature for 1 hr to 3 hrs.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained from step (a) is carried out by using any method selected from crystallisation, recrystallization, distillation, extraction, filtration, chromatographic separation and combinations thereof.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained is having purity in the range of 95% to 99.99% by HPLC, preferably 98% to 99.99% by HPLC.
Another embodiment of the present invention provides a process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 is carried out by:
i. dissolving the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in solvent to obtain a mixture;
ii. cooling the mixture -5oC to 5oC and adjusting a pH in the range of 7 to 9 by using a base to obtain a reaction mixture;
iii. stirring the reaction mixture for a period in the range of 8 hrs to 14 hrs;
iv. extracting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 with a solvent;
v. evaporating the solvent and eluting through a column of silica gel using a solvent to obtain a pure the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
Another embodiment of the present invention provides a process for purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein the solvent is dichloromethane, water, methanol, ethanol and combinations thereof.
Another embodiment of the present invention provides a process for purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4, wherein eluting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 through a column of silica gel is carried out by using a dichloromethane- methanol mixture in the ratio 9:1 respectively.
The details of the present invention are provided in the examples given below to illustrate the invention only and therefore they should not be construed to limit the scope of invention.

Examples
Example 1: Preparation of Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 using dichloromethane (DCM) as solvent
Using a three necked 50 ml round bottom flask, a solution of 2,4-ditert butyl phenol D2 (0.3 g ,0.144mmol) in 1.1 ml of methylene dichloride (DCM) was prepared under nitrogen atmosphere. To this solution was added triethylamine (0.29 g, 0.288mmol) and stirred for 5 minutes. Then added Phosphorus oxychloride (0.23 g, 0.15mmol) to the reaction mass at RT. The reaction mass was maintained for 18hrs at RT. then added 1.1 ml of DM water and stirred for 1.5 h. evaporated the solvent and filtered the crude product.
Reaction scheme:

Example 2: Purification of crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4
The isolated crude compound from example 1 was dissolved in Dichloromethane (Dry) and chilled water under stirring. Cooled to 0-5ºC. then pH adjusted to 8.0 using 0.5 N sodium hydroxide solution. Raised to room temperature. Stirred for overnight. Extracted with dichloromethane and then combined organic layer washed with cold water for three times. Dried the separated organic layer using anhydrous sodium sulphate and solvent was removed by vacuum at below 20ºC. Purification was completed by passing the compound through a column of silica gel using a DCM–methanol mixture as eluent (9:1). Yield: 0.3 g (43.5%).

Example 3: Preparation of Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 using toluene as solvent
Using a three necked 50 ml round bottom flask, a solution of 2,4-ditert butyl phenol D2 (1 g ,0.48 mmol) in 3.7 ml of toluene was prepared under nitrogen atmosphere. To this solution was added triethylamine (0.97 g, 0.96 mmol) and stirred for 5 minutes. Heated to reflux. Then added Phosphorus oxychloride (0.77 g, 0.50 mmol) to the reaction mass at reflux. Maintained the reaction mass for 3 hrs. then cooled to RT and added 3.7 ml of DM water and stirred for 1 h. evaporated the solvent and filtered the product.
Reaction scheme:

Example 4: Purification of crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4
Purification of crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 was carried out as per process described in example 1.

Example 5: Characterisation of Bis(2,4-di-tert-butylphenyl) hydrogen phosphate
Characterisation of Bis(2,4-di-tert-butylphenyl) hydrogen phosphate is carried out by using 1H NMR (figure 1 & 2) and Mass spectroscopy (figure 3).
 
We claim:
1. A process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4,

the process comprising:
a) contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in a solvent under N2 to obtain a crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and
b) purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained from step (a) in a solvent or solvent mixture to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
2. The process as claimed in claim 1, wherein the reagent is selected from Chlorine gas (Cl₂), Sodium hypochlorite (NaOCl), Calcium hypochlorite (Ca(OCl)₂), Potassium hypochlorite (KOCl), Chlorine dioxide (ClO₂), Hydrochloric acid (HCl), Phosphorus pentachloride (PCl₅) and Phosphorus trichloride (PCl₃), Phosphorus oxychloride (POCl₃), Thionyl chloride (SOCl₂) and combinations thereof.
3. The process as claimed in claim 1, wherein the reagent is phosphorus oxychloride (POCl₃).
4. The process as claimed in claim 1, wherein the base is selected from sodium alkoxide, potassium alkoxide, butyl lithium, triethyl amine (TEA), di-isopropyl ethylamine, pyridine, piperidine, quinoline, 4-dimethylaminopyridine, amine, sodium hydroxide, potassium hydroxide, strontium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, cesium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium carbonate, sodium carbonate, strontium carbonate, cesium carbonate, sodium sulfide, sodium hydride and combinations thereof.
5. The process as claimed in claim 1, wherein the solvent is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, tert-butanol, n-pentyl alcohol, isoamyl alcohol, ethylene glycol, propylene glycol, glycerol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetonitrile, dioxane, N-methyl pyrrolidone, methylene chloride, chloroform, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or ethylene glycol monomethyl ether, toluene, xylene, cumene, cymene, N-methylpyrrolidone and combinations thereof.
6. The process as claimed in claim 1, wherein contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in an inert solvent is carried out a time period in the range of 30min to 18 hrs.
7. The process as claimed in claim 1, wherein the pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained is having purity in the range of 95% to 99.99% by HPLC, preferably 98% to 99.99% by HPLC.
8. The process as claimed in claim 1, wherein purifying the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 is carried out by:
i. dissolving the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in solvent to obtain a mixture;
ii. cooling the mixture -5oC to 5oC and adjusting a pH in the range of 7 to 9 by using a base to obtain a reaction mixture;
iii. stirring the reaction mixture for a period in the range of 8 hrs to 14 hrs;
iv. extracting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 with a solvent to obtain extracted Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4;
v. evaporating the solvent from extracted Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 and eluting through a column of silica gel using a solvent to obtain a pure the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
9. The process as claimed in claim 8, wherein solvent is dichloromethane, water, methanol, ethanol, propanol and combinations thereof.
10. The process as claimed in claim 8, wherein eluting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 through a column of silica gel is carried out by using a dichloromethane- methanol mixture in the ratio 9:1 respectively.

Dated this: 20th March, 2025

Vijaykumar Shivpuje
IN/PA-1096
The Agent for the Applicant/s

To
The Controller of Patents,
The Patent Office, Mumbai/Delhi/Chennai/Kolkata
ABSTRACT

A PROCESS FOR PREPARING BIS(2,4-DI-TERT-BUTYLPHENYL) HYDROGEN PHOSPHATE-D4

The present invention provides Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4. The process is carried out by: (a) contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in an inert solvent to obtain Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and (b) purifying the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in solvent or mixture of solvent to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.

, Claims:We claim:
1. A process for preparing Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4,

the process comprising:
a) contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in a solvent under N2 to obtain a crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4; and
b) purifying the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained from step (a) in a solvent or solvent mixture to obtain a pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
2. The process as claimed in claim 1, wherein the reagent is selected from Chlorine gas (Cl₂), Sodium hypochlorite (NaOCl), Calcium hypochlorite (Ca(OCl)₂), Potassium hypochlorite (KOCl), Chlorine dioxide (ClO₂), Hydrochloric acid (HCl), Phosphorus pentachloride (PCl₅) and Phosphorus trichloride (PCl₃), Phosphorus oxychloride (POCl₃), Thionyl chloride (SOCl₂) and combinations thereof.
3. The process as claimed in claim 1, wherein the reagent is phosphorus oxychloride (POCl₃).
4. The process as claimed in claim 1, wherein the base is selected from sodium alkoxide, potassium alkoxide, butyl lithium, triethyl amine (TEA), di-isopropyl ethylamine, pyridine, piperidine, quinoline, 4-dimethylaminopyridine, amine, sodium hydroxide, potassium hydroxide, strontium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, cesium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium carbonate, sodium carbonate, strontium carbonate, cesium carbonate, sodium sulfide, sodium hydride and combinations thereof.
5. The process as claimed in claim 1, wherein the solvent is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, tert-butanol, n-pentyl alcohol, isoamyl alcohol, ethylene glycol, propylene glycol, glycerol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetonitrile, dioxane, N-methyl pyrrolidone, methylene chloride, chloroform, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or ethylene glycol monomethyl ether, toluene, xylene, cumene, cymene, N-methylpyrrolidone and combinations thereof.
6. The process as claimed in claim 1, wherein contacting 2,4-ditert butyl phenol D2 with a reagent in presence of a base in an inert solvent is carried out a time period in the range of 30min to 18 hrs.
7. The process as claimed in claim 1, wherein the pure Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 obtained is having purity in the range of 95% to 99.99% by HPLC, preferably 98% to 99.99% by HPLC.
8. The process as claimed in claim 1, wherein purifying the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 is carried out by:
i. dissolving the crude Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 in solvent to obtain a mixture;
ii. cooling the mixture -5oC to 5oC and adjusting a pH in the range of 7 to 9 by using a base to obtain a reaction mixture;
iii. stirring the reaction mixture for a period in the range of 8 hrs to 14 hrs;
iv. extracting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 with a solvent to obtain extracted Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4;
v. evaporating the solvent from extracted Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 and eluting through a column of silica gel using a solvent to obtain a pure the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4.
9. The process as claimed in claim 8, wherein solvent is dichloromethane, water, methanol, ethanol, propanol and combinations thereof.
10. The process as claimed in claim 8, wherein eluting the Bis(2,4-di-tert-butylphenyl) hydrogen phosphate-d4 through a column of silica gel is carried out by using a dichloromethane- methanol mixture in the ratio 9:1 respectively.