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
“METHOD FOR PRODUCING DEUTERATED AMMONIUM DINITRAMIDE (ADN-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 method for producing deuterated ammonium dinitramide (ADN-d4). More specifically, the invention concerns a single-step method for producing ADN-d4 from potassium dinitramide (KDN) or N-guanylurea dinitramide (GUDN) using deuterated solvents, deuterated water, deuterated isopropanol and/or deuterated hexane.

BACKGROUND OF INVENTION
Ammonium dinitramide (ADN), with the chemical formula NH₄N(NO₂)₂, is a high-energy oxidizer of significant interest in propellant and explosives formulations due to its favourable performance characteristics and environmentally benign combustion byproducts- nitrogen, oxygen, and water. The deuterated analogue, deuterated ammonium dinitramide (ADN-d), in which the ammonium cation is partially or fully replaced by ND₄⁺, is of particular interest for:
• Mechanistic and kinetic isotope effect (KIE) studies in decomposition pathways,
• Isotopic tracing in combustion and thermal degradation studies,
• Nuclear magnetic resonance (NMR) spectroscopy as a labelled reference,
• Tailored energetic profiles due to isotope effects on detonation velocities and sensitivities.
While methods for synthesizing non-deuterated ADN are well-established, there is limited disclosure in the prior art regarding the synthesis of deuterated ADN (ADN-d).
Conventional ADN synthesis typically involves the reaction of an N-nitramino compound (e.g., nitramide) with ammonium salts in the presence of a strong acid like sulfuric acid and nitrating agents. For instance:
WO2020060451A1 discloses a method for preparing ammonium dinitramide (ADN) from guanylurea dinitramide (GUDN). The method involves reacting guanylurea dinitramide with ammonium sulfate in a reaction mixture comprising water and optionally acetone, followed by ion exchange to obtain ammonium dinitramide.
The method disclosed in WO’451 exhibits several limitations and drawbacks, particularly when adapted for sensitive or isotopically labelled systems like deuterated ADN (AND-d4). The process employs standard ammonium sulfate (NH₄)₂SO₄, which is unsuitable for preparing deuterated ADN (ND₄N(NO₂)₂). The reaction conditions, particularly aqueous acidic environments, are prone to H/D exchange, risking loss of deuterium and reducing isotopic purity in deuterated ADN. The method does not provide strategies for preserving deuterium throughout the reaction and work-up stages. Although acetone improves filtration properties and solubility balance, its use: (a) Increases volatility and flammability risks; (b) May interfere with deuterated systems due to possible isotope exchange at labile hydrogen positions; (c) Adds cost and regulatory handling requirements in large-scale operations.
US5659080A describes a synthetic method for ammonium dinitramide (ADN) involves forming urea nitrate from urea and diluted nitric acid, converting it to nitrourea with sulfuric acid, followed by nitration using nitronium tetrafluoroborate and ammonia gas addition. The product is purified through sequential filtration and solvent treatments, yielding high-purity ADN.
Although the process of US’ 080 uses readily available urea as a starting material, the synthesis involves multiple sequential reaction steps (urea nitrate formation, nitrourea synthesis, nitration, ammonia addition, multiple filtration and concentration stages). This multi-step nature increases the overall process complexity and time. The method requires handling of concentrated sulfuric acid and nitronium tetrafluoroborate, which are highly corrosive, toxic, and pose significant safety risks during scale-up operations. Introduction of ammonia gas necessitates specialized equipment and strict safety protocols to avoid exposure and control reaction conditions, complicating the process. The method does not address incorporation or retention of isotopes (e.g., deuterium), limiting its utility for producing labeled ammonium dinitramide derivatives.
However, none of these references explicitly disclose or enable a method for replacing the hydrogen atoms in the ammonium ion with deuterium atoms to form ND₄N(NO₂)₂, nor do they describe optimized reaction conditions for the retention of deuterium during nitration or neutralization.
Moreover, isotopic exchange of NH₄⁺ to ND₄⁺ under acidic conditions is not trivial, as deuterium is susceptible to exchange back to protium (¹H) in aqueous and acidic environments. Therefore, a robust method that enables the incorporation and retention of deuterium in the ammonium cation of ADN is highly desirable.
Known processes for producing non-deuterated ADN typically involve reacting GUDN with ammonium sulphate in an aqueous solution. However, these methods encounter challenges, such as the poor solubility of guanylurea sulfate or potassium sulphate, leading to sticky precipitates that are difficult to handle and reduce yield.
Furthermore, elevated temperatures and large volumes of water are often required, increasing energy consumption and waste. Applying these traditional methods to produce deuterated ADN would likely face similar challenges, along with the added complexity and cost of using deuterated starting materials and solvents.
Therefore, there is a need for an improved method for producing deuterated ADN that overcomes these limitations. Specifically, there is a need for a process that: (a) Provides a higher yield of deuterated ADN; (b) Reduces the amount of solvent required; (c) Produces a less sticky and more easily filterable byproduct; (d) Can be carried out at controller reaction conditions such as lower temperatures; (e) Involves fewer process steps; (f) Efficiently incorporates deuterium into the final product.
The present invention addresses these needs by providing an efficient, reproducible method for producing deuterated ammonium dinitramide, minimizing isotopic dilution or loss and yielding a product with high deuterium content and purity.

OBJECTS OF THE INVENTION
It is an object of the present invention to provide a method for producing deuterated ammonium dinitramide (ADN-d4) from potassium dinitramide (KDN) or N-guanylurea dinitramide (GUDN) in a single step.
It is another object of the invention to provide a method for producing ADN-d4 that achieves a higher yield of ADN-d4 compared to known methods.
It is a further object of the invention to provide a method for producing ADN-d4 that requires a reduced amount of solvent.
It is yet another object of the invention to provide a method for producing ADN-d4 that produces a less sticky and more easily filterable potassium sulphate or N-guanylurea sulphate byproduct.
It is still another object of the invention to provide a method for producing ADN-d4 that can be carried out at controlled reaction conditions e.g. lower temperatures.
It is a further object of the invention to provide a method that is simpler and more efficient than existing methods.

SUMMARY OF THE INVENTION
One of the aspects of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4)
,
the method comprising:
a) treating a precursor with a deuterated ammonium source in a solvent to obtain a reaction mass;
b) contacting the reaction mass obtained from step (a) with a solvent to obtain a precipitated mass;
c) filtering the precipitated mass obtained from step (b) to obtain a filtrate and a solid residue;
d) concentrating the filtrate obtained from step (c) to obtain crude ADN-d4;
e) purifying the crude ADN-d4 and drying to obtain a pure ADN-d4 with isotopic purity in the range of 50% to 99.99%, preferably 90% to 99.99%
Another aspect of the present invention provides a method for purifying crude AND-d4 to obtain pure ADN-d4, wherein said method is carried out by recrystallisation using solvent selected from Deuterium oxide (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane(C6D6), Deuterated cyclohexane and combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION
For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art.
The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described.
Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional and structural details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
In the specification different terms are used for describing the invention. The definitions of the terms are provided below.
The term ‘deuterated ammonium dinitramide (ADN-d4)’ used herein refers to ammonium dinitramide (ADN) where hydrogen atoms of ammonium cations [NH4]+ are replaced with deuterium atoms. The terms ‘deuterated ammonium dinitramide’ and ‘ADN-d4’ are used interchangeably throughout the specification of present invention.
The term ‘precursor’ used herein refers to a compound that participates in a chemical reaction that produces desired final product. It may be starting material or intermediate. In the present invention precursor is potassium dinitramide (KDN) or N-guanylurea-dinitramide (GUDN) used as precursor for producing ADN-d4.
The term ‘deuterated ammonium source’ used herein refers to a reagent that provides ND₄⁺ ions instead of NH₄⁺, which is produced by replacing one or more hydrogen atoms by deuterium (²H or D), the stable isotope of hydrogen.
The term ‘solvent’ used herein refers to a medium, usually a liquid, in which solutes are dissolved to form a solution. In the present invention, solvent used is polar and/or non-polar solvent. The solvent includes such as but is not limit to alcohols, ethers, ketones, amides, acids, esters, acetonitrile (ACN), halogenated solvent(s) and/or deuterated form of alcohols, ethers, ketones, acids, esters, and/or deuterated halogenated solvent(s). Solvent may be used deuterated form of above-mentioned solvents.
The term ‘reaction mass’ used herein refers to the total mass obtained after completion of reaction (product formation) which includes precursor, solvent/s catalysts (if any), intermediates, products and by products.
The term ‘precipitated mass’ used herein refers to the solid material (precipitate) that forms by adding solvent and/or anti-solvent, solid obtained which further separates out from a solution by filtration or decantation, any other methods known in prior art.
The term ‘crude ADN-d4’ used herein refers to ADN-d4 that has been isolated from filtrate but has not yet been purified. It may contain minimal amount of impurities such as but is not limited to unreacted precursor, by-products, traces of solvents.
The term ‘pure ADN-d4’ used herein refers to ADN-d4 with a uniform and definite composition and distinct physical and chemical properties, having isotopic purity in the range of 50% to 99.99%, preferably 60% to 99.99%, more preferably 70% 99.99%, most preferably 90% to 99.99% and it contains no detectable impurities within the limits of analytical methods used.
The term ‘Isotopic purity’ used herein refers to the extent to which the deuterium (²H or D) atoms in the molecule replace protium (¹H) atoms in the ammonium ion (ND₄⁺ vs. NH₄⁺) in deuterated ammonium dinitramide (ADN-d4). It is typically expressed as a percentage of deuterium incorporation in the final product, ADN-d4.
One of the embodiments of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4)
,
the method comprising:
a) treating a precursor with a deuterated ammonium source in a solvent to obtain a reaction mass;
b) contacting the reaction mass obtained from step (a) with a solvent to obtain a precipitated mass;
c) filtering the precipitated mass obtained from step (b) to obtain a filtrate and a solid residue;
d) concentrating the filtrate obtained from step (c) to obtain crude ADN-d4; and
e) purifying the crude ADN-d4 and drying to obtain a pure ADN-d4 with isotopic purity in the range of 50% to 99.99%, preferably 90% to 99.99%.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein the precursor is potassium dinitramide (KDN) or N-guanylurea-dinitramide (GUDN).
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein deuterated ammonium source is selected from deuterated ammonium sulphate (ammonium sulphate-d8), deuterated ammonia (ND4) and combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein treating the precursor with an ammonium source in a solvent to obtain a reaction mass is carried out at a temperature in the range of 25oC to 100oC for a time period in the range of 5min to 120min.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent is polar and/or non-polar solvent.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent used in step (a) is selected from Deuterium oxide/water (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent used in step (a) is deuterated water (D2O).
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent used in step (b) is selected from Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and/or combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent used in step (b) is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane and/or combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein the filtrate comprising ADN-d4.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein the solid residue comprising ammonium sulphate or N-guanylurea sulphate salt.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein crude ADN-d4 is purified by any conventional purification techniques such as but is not limited to crystallisation, recrystallisation, extraction, chromatographic techniques, Lyophilization and combinations thereof.
In an preferred embodiment, crude ADN-d4 is purified by recrystallisation techniques.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein purifying the crude AND-d4 to obtain pure ADN-d4 is carried out by recrystallisation using solvent selected from Deuterium oxide (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane(C6D6), Deuterated cyclohexane and combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent used for recrystallisation is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane (C6D6) or combinations thereof.
Another embodiment of the present invention provides a method for producing deuterated ammonium dinitramide (ADN-d4), wherein solvent is selected from water, acid, alcohols, esters, ketone, amide, hydrocarbons, deuterated acid, deuterated alcohols, deuterated esters, deuterated ketone, deuterated amide, deuterated hydrocarbons and combinations thereof.
In an embodiment of the present invention, the pure ADN-d4 is obtained with yield in the range of 50% to 99.99% (w/w).
Advantages of the present Invention:
The method of the present invention offers several advantages over prior art methods for producing ADN-d4 from GUDN/ KDN:
i. Higher Yield: The use of deuterated solvent increases the solubility of KDN/ GUDN, leading to a more complete reaction and a higher yield of deuterated ADN (ADN-d4).
ii. Reduced Solvent Usage: The method requires significantly less deuterated water (D₂O) compared to traditional aqueous methods, leading to cost savings.
iii. Improved Filterability: The guanylurea sulfate/ potassium sulphate, byproduct, is produced as a less sticky and more easily filterable solid, simplifying the separation process.
iv. Lower Reaction Temperature: The method can be carried out at lower temperatures, reducing energy consumption and improving safety.
v. Less unit of operations: The method provides a direct, single-step conversion of GUDN/KDN to deuterated ADN (ADN-d4), simplifying the process and reducing the number of unit operations.
vi. Cost-Effective: The reduced solvent usage, lower reaction temperatures, and improved yield contribute to a more cost-effective process.
vii. Efficient Deuterium Incorporation: The method efficiently incorporates deuterium from ammonium sulphate-D8 into the final deuterated ADN product (ADN-d4).
The following examples are provided to illustrate the invention and are not intended to limit the scope of the invention.
Examples
1. PREPARATION OF ADN-d4:
40g (0.276 mol) of KDN and 40 g (0.303mol) of ammonium sulphate-D8 are dissolved in 80 ml of D2O, respectively. After mixing the two solutions, 800 ml deuterated-2-propanol was added to yield white precipitate, potassium sulphate. This was removed by filtration and subsequently the filtrate was concentrated to obtain the solid through distillation. After the recrystallization using deuterated 2-propanol and hexane, the obtained solid was filtered and washed and then dried at 50oC for 3 hrs. The amount of solid product was shown to be increased from 30 g to ~100 g scale maintaining the isotopic purity 99.99%.
Scheme 1:

2. Preparation of AND-d4:
Direct Method by conversion of GUDN to ADN-d4 as shown in scheme 2, 150 ml of D2O was added to the 1 L double jacketed reactor and subsequently 10 g (0.0478 mol) GUDN and 7.58 g (0.0574 mol) of ammonium sulphate-d8 were also added. After completion of the addition, the reaction solution was heated to 100oC and the reaction was allowed to proceed for 5 min. After the addition of 1500 ml deuterated 2-propanol the resulting solid is filtered and distilled. Again, deuterated 2-propanol is added in a second step and the remaining solid is filtered. The resulting liquid phase after filtration is distilled again to obtain the solid ADN-d4. Isotopic purity 99.99%.
Scheme 2:

We claim:
1. A method for producing deuterated ammonium dinitramide (ADN-d4)
,
the method comprising:
a) treating a precursor with deuterated ammonium source in a solvent to obtain a reaction mass;
b) contacting the reaction mass obtained from step (a) with a solvent to obtain precipitated mass;
c) filtering the precipitated mass obtained from step (b) to obtain a filtrate and a solid residue;
d) concentrating the filtrate obtained from step (c) to obtain crude ADN-d4;
e) purifying the crude ADN-d4 and drying to obtain a pure ADN-d4 with isotopic purity in the range of 50% to 99.99%, preferably 95% to 99.99%.
2. The method as claimed in claim 1, wherein the precursor is Potassium dinitramide (KDN) or N-guanylurea-dinitramide (GUDN).
3. The method as claimed in claim 1, wherein deuterated ammonium source is selected from deuterated ammonium sulphate (ammonium sulphate-d8), deuterated ammonia (ND4) and combinations thereof.
4. The method as claimed in claim 1, wherein treating the precursor with an ammonium source in a solvent to obtain a reaction mass is carried out at a temperature in the range of 25oC to 100oC for a time period in the range of 5min to 120min.
5. The method as claimed in claim 1, wherein solvent used in step (a) is selected from Deuterium oxide/water (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and combinations thereof, preferably deuterated water (D2O).
6. The method as claimed in claim 1, wherein solvent used in step (b) is selected from Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and/or combinations thereof.
7. The method as claimed in claim 8, wherein solvent used in step (b) is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane and/or combinations thereof.
8. The method as claimed in claim 1, wherein the filtrate comprising ADN-d4; and wherein the solid residue comprising ammonium sulphate or N-guanylurea sulphate.
9. The method as claimed in claim 1, wherein purifying the crude AND-d4 to obtain pure ADN-d4 is carried out by recrystallisation using solvent selected from Deuterium oxide (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane(C6D6), Deuterated cyclohexane and combinations thereof.
10. The method as claimed in claim 13, wherein solvent used for recrystallisation is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane (C6D6) or combinations thereof.

Dated this: 21st May, 2025

Vijaykumar Shivpuje
IN/PA-1096
Agent for the Applicant/s
To
The Controller of Patents
The Patent Office, Mumbai

ABSTRACT
“METHOD FOR PRODUCING DEUTERATED AMMONIUM DINITRAMIDE (ADN-d4)”

The present invention relates to a method for producing deuterated ammonium dinitramide (ADN-d4). More specifically, the invention concerns a single-step method for producing ADN-d4 from potassium dinitramide (KDN) or guanylurea dinitramide (GUDN) using deuterated water and deuterated isopropanol. The method for producing deuterated ammonium dinitramide (ADN-d4) comprising: (a) treating a precursor with deuterated ammonium source in a solvent to obtain a reaction mass; (b) contacting the reaction mass with a solvent to obtain precipitated mass; (c) filtering the precipitated mass to obtain a filtrate and a solid residue; (d) concentrating the filtrate to obtain crude ADN-d4; (e) purifying the crude ADN-d4 and drying to obtain a pure ADN-d4 with isotopic purity in the range of 50% to 99.99%.

, Claims:We claim:
1. A method for producing deuterated ammonium dinitramide (ADN-d4)
,
the method comprising:
a) treating a precursor with deuterated ammonium source in a solvent to obtain a reaction mass;
b) contacting the reaction mass obtained from step (a) with a solvent to obtain precipitated mass;
c) filtering the precipitated mass obtained from step (b) to obtain a filtrate and a solid residue;
d) concentrating the filtrate obtained from step (c) to obtain crude ADN-d4;
e) purifying the crude ADN-d4 and drying to obtain a pure ADN-d4 with isotopic purity in the range of 50% to 99.99%, preferably 95% to 99.99%.
2. The method as claimed in claim 1, wherein the precursor is Potassium dinitramide (KDN) or N-guanylurea-dinitramide (GUDN).
3. The method as claimed in claim 1, wherein deuterated ammonium source is selected from deuterated ammonium sulphate (ammonium sulphate-d8), deuterated ammonia (ND4) and combinations thereof.
4. The method as claimed in claim 1, wherein treating the precursor with an ammonium source in a solvent to obtain a reaction mass is carried out at a temperature in the range of 25oC to 100oC for a time period in the range of 5min to 120min.
5. The method as claimed in claim 1, wherein solvent used in step (a) is selected from Deuterium oxide/water (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and combinations thereof, preferably deuterated water (D2O).
6. The method as claimed in claim 1, wherein solvent used in step (b) is selected from Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane, Deuterated cyclohexane and/or combinations thereof.
7. The method as claimed in claim 8, wherein solvent used in step (b) is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane and/or combinations thereof.
8. The method as claimed in claim 1, wherein the filtrate comprising ADN-d4; and wherein the solid residue comprising ammonium sulphate or N-guanylurea sulphate.
9. The method as claimed in claim 1, wherein purifying the crude AND-d4 to obtain pure ADN-d4 is carried out by recrystallisation using solvent selected from Deuterium oxide (D2O), Deuterated chloroform (CDCl₃), Deuterated dimethyl sulfoxide (DMSO-d₆), Deuterated methanol (CD₃OD), Deuterated ethanol (C₂D₅OD), Deuterated isopropanol ((CD₃)₂CHOD), Deuterated tert-butanol ((CD₃)₃COD), Deuterated acetone (acetone-d₆), Deuterated benzene (C₆D₆), Deuterated acetonitrile (CD₃CN), Deuterated toluene (C₆D₅CD₃), Deuterated tetrahydrofuran (THF-d₈), deuterated hexane(C6D6), Deuterated cyclohexane and combinations thereof.
10. The method as claimed in claim 13, wherein solvent used for recrystallisation is Deuterated isopropanol ((CD₃)₂CHOD), deuterated hexane (C6D6) or combinations thereof.