DESC:FIELD OF THE INVENTION
The invention relates to a process for purification of acaricide and fungicides. More particularly the present invention relates to a process for purification of Propargite and Propiconazole using Short Path Distillation (SPD) and/or Wiped Film Evaporation (WFE).
BACKGROUND OF THE INVENTION
Propargite is a chemical compound commonly used as an acaricide, i.e., a pesticide specifically designed to target and control mites. It is often utilized in agricultural settings to protect crops from various types of mites that can damage plants. Propargite works by interfering with the mites' nervous system, ultimately leading to their death.
Propiconazole (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1,2,4-triazole) is a triazole fungicide, and is a diastereomeric mixture of four stereoisomers. All four stereoisomers of propiconazole provide biological activity. The intrinsic activity of each isomer is different from pathogen to pathogen. The broad spectrum and high level of activity of propiconazole is the result of the combined activity of all isomers. Propiconazole-4H-1,2,4-triazole (4-[[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-4H-1,2,4-triazole), also known as 4H impurity is an unwanted stereoisomer and generally present in about 15% in the final propiconazole prepared by conventional methods.
The commercially produced propargite technical has purity of 89-90% and is inconsistent during commercial scale production. This is mainly due to the formation of by-product impurities which have a high boiling point making removal difficult at commercial scale. For instance, the commercially available propargite technical often contains indeterminate amounts of impurities such as dipropargyl sulfite (DPS).
Similarly, commercially produced propiconazole, often contains the 12-15% of 4-H isomer as an impurity (4-[[2- (2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-4H-1,2,4-triazole). Additionally, there are other solvent impurities and high boiler impurities present in the technical. Thus, the technical purity of Propiconazole and Propargite prepared using conventional techniques usually range from 85-90% by weight respectively, due to the presence of these impurities and thereby such technical is not suitable for making desired formulations.
Further, toluene is used as solvent in the preparation of propiconazole or propargite and this low boiler solvent (toluene) can be removed by conventional vacuum distillation or evaporation during product isolation, other high boiler impurities cannot be distilled out using the conventional techniques under conventional distillation set-up. Moreover, the higher content of impurities such as DPS destabilizes the subsequent formulation for example liquid agrochemical formulation. Additionally, Propargite technical is likely to undergo degradation when subjected to high- temperature conditions. Therefore, it is essential to have high purity Propargite to prepare a stable agrochemical formulation.
Owing to these challenges, there have been some developments whereby use of inert non-polar solvents, such as pet ether, has been proposed for manufacturing Propargite to remove excess thionyl chloride under vacuum. Such a technique has resulted in control of the unwanted DPS. However, it has been observed that during the solvent-stripping process, the chlorosulfinate intermediate tends to degrade further. This leads to the formation of a dimer impurity, which eventually results in technical purity levels lower than 90%.
On the other hand, using lower or optimum equivalents of thionyl chloride initially leads to a relatively higher content of unreacted compound, 2-(4-(Tert-butyl) phenoxy) cyclohexanol (TBPC). However, this also results in higher dimer formation at the end of the reaction. In view thereof, there is a need for a simple, efficient, and robust technological solution to address the issues pertaining to purity, especially on a commercial scale.
The existing techniques for purification of Propargite and/or Propiconazole involve either a conventional batch reactor or an agitated Thin Film Evaporator (ATFE) operating under high vacuum. However, these methods are not very effective in removing high boiler impurities due to the long vapor travel path.
However, the methods described in the art are expensive, not practical for production on an industrial scale and not satisfactory with regard to yield and purity of the desired technical product which is suitable for preparing stable formulations. In view of the above, methods are needed for a purification process which addresses at least the aforementioned problems.
Therefore, there remains a need to develop a simple and commercially viable process for the purification of agrochemicals, particularly Propargite and/or Propiconazole. The present invention provides an industrially viable process to obtain highly pure Propargite and/or Propiconazole with excellent yields without any active degradation in quality.
SUMMARY OF THE INVENTION
In an aspect, the present invention provides a process for purification of Propargite and/or Propiconazole.
In another aspect, the present invention provides a simple, cost effective and industrially viable process for purification of highly pure Propargite and/or Propiconazole with excellent yields and reduced impurities, using short Path Distillation (SPD) and/or wiped film evaporation (WFE).
In another aspect, the present invention provides Propargite and/or Propiconazole with purity more than 90%.
In an aspect the present invention provides pure propargite having purity of about 95% and DPS impurity less than about 0.5%.
In an aspect the present invention provides pure propiconazole having purity of about 95% and 4H impurity less than about 5%.
In yet another aspect, Propargite and/or Propiconazole is purified by a process comprising the steps of,
a) subjecting crude propargite or propiconazole to a short path distillation and/or a wiped film evaporator at predetermined feed rate and b) isolating propargite or propiconazole with high purity as a bottom and impurity at the distillate end.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1: It represents a flow diagram of process for purification of propargite or propiconazole according to the present invention.
DESCRIPTION OF THE INVENTION
Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by persons of ordinary skill in the art to which this subject matter pertains.
The term “a” or “an” as used herein includes the singular and the plural, unless specifically stated otherwise. Therefore, the terms “a,” “an,” or “at least one” are used interchangeably in this application.
Throughout the application, descriptions of various embodiments are described using the term “comprising”; however, it will be understood by one of skill in the art, that in some specific instances, an embodiment can be described using the language “consisting essentially of’ or “consisting of.”
The term “about” herein specifically includes ±10 % from the indicated values in the range. In addition, the endpoints of all ranges directed to the same component or property herein are inclusive of the endpoints, are independently combinable, and include all intermediate points and ranges.
The term “dipropargyl sulfite” and “DPS” or “DPS impurity” are used synonymously. The term “4-H isomer” or “4H impurity” or “4-[[2- (2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-4H-1,2,4-triazole” are used synonymously.
The term “% w/w” or “%” or “% by weight” as used herein refers to the percentage of a component by weight in relation to the total weight of a product.
It is understood that where a parameter range is provided, all integers within that range, and tenths thereof, are also provided by the invention as if the integers and tenths thereof are expressly described herein. For example, “0.1% to 70%” includes 0.1%, 0.2%, 0.3%, 0.4%, 0.5% etc. up to 70%.
As used herein, all numerical values or numerical ranges include integers within such ranges and fractions of the values or the integers within ranges unless the context clearly indicates otherwise. Thus, for example, reference to a range of 90-100%, includes 91%, 92%, 93%, 94%, 95%, 95%, 97%, etc., as well as 91.1%, 91.2%, 91.3%, 91.4%, 91.5%, etc., 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, etc., and so forth.
In an aspect the present invention provides a process for purification of the crude product particularly, propargite or propiconazole.
The present invention provides a process for purification of propargite or propiconazole which provides a simple, efficient, and robust technological solution to address the issues in the existing solutions pertaining to purity, especially on a commercial scale. In the present context, suitable sulfite ester acaricides for example triazole and/or conazole can be purified by the present process using short path distillation and/or a wiped film evaporator.
Suitable triazoles can be selected from azaconazole, bitertanol, bromuconazole, cyproconazole, difenoconazole, diniconazole, epoxiconazole, etaconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, imibenconazole, ipconazole, mefentrifluconazole, metconazole, myclobutanil, penconazole, propiconazole, simeconazole, tebuconazole, tetraconazole, triadimefon, triadimenol, triticonazole and prothioconazole.
In an embodiment, high purity propargite and/or propiconazole is achieved through efficient purification of the crude using novel distillation techniques such as Short Path Distillation (SPD) and/or Wiped Film Evaporation (WFE).
In an embodiment, the present invention provides a process for purification of an agrochemical active ingredient comprising
subjecting crude agrochemical active ingredient to short path distillation or wide film evaporation and
isolating pure agrochemical active ingredient having reduced unwanted impurities,
the agrochemical active ingredient is selected from propargite and propiconazole.
In an embodiment the present invention provides a process for purifying an agrochemical selected from propargite and/or propiconazole comprising
subjecting crude agrochemical active ingredient selected from propargite and/or propiconazole to short path distillation or wiped film evaporator and
isolating pure agrochemical selected from propargite and/or propiconazole with reduced impurities.
In an embodiment, the crude agrochemical selected from propargite and propiconazole subjected for short path distillation comprises propargite or propiconazole with high boiling and low boiling impurities such as DPS impurity upto 5-7%, 4H impurity upto 12-15%, toluene or mixtures thereof.
In an embodiment, the reduced impurities comprise high boiling and low boiling impurities such as DPS impurity less than 0.5%, 4H impurity less than 5%.
In an embodiment the crude agrochemical active ingredient is preheated at 50-80°C, preferably at at 50-60°C.
In an embodiment the process for purifying propargite comprises
subjecting crude propargite to short path distillation or wiped film evaporator and
isolating pure propargite with reduced DPS impurity.
wherein DPS impurity is reduced to less than 0.5%.
In an embodiment the process for purifying propargite comprises
subjecting crude preheated propargite to short path distillation or wiped film evaporator and
isolating pure propargite with reduced DPS impurity.
wherein DPS impurity is reduced to less than 0.5%.
In an embodiment crude propargite is preheated at 50-80°C, preferably at at 50-60°C.
In an embodiment the process for purifying propiconazole comprises
subjecting crude propiconazole to short path distillation or wiped film evaporator and
isolating pure propiconazole with reduced 4H impurity.
wherein 4H impurity is reduced to less than 5%.
In an embodiment, the short path distillation for propargite is performed at temperature in the range from 100°C to 250°C. In an embodiment, the short path distillation for propargite is performed at temperature in the range from 100°C to 150°C. In an embodiment, the short path distillation for propargite is performed at temperature in the range from 120°C to 150°C.
In an embodiment, the short path distillation for propiconazole is performed at temperature in the range from 100°C to 250°C. In an embodiment, the short path distillation for propiconazole is performed at temperature in the range from 150°C to 250°C. In an embodiment, the short path distillation for propiconazole is performed at temperature in the range from 150°C to 200°C.
In an embodiment, the feed residence time is in the range of about 5 seconds to 30 seconds.
In an embodiment, the feed rate in short path distillation is about 15 to 20 kg/hr.
In an embodiment, the process using SPD and WFE is operated in the range of 0.1 to 1.0 torr pressure. In an embodiment, the process using SPD and WFE is operated at below 1.0 torr pressure. In some embodiments, the process using SPD and WFE is operated at below 0.1 torr pressure.
The present invention utilizes a Short Path Distillation Unit (SPDU) and/or a Wiped Film Evaporator (WFE) for purification of Propiconazole and/or Propargite. The degree of purification obtained by present process is such that the unwanted impurities such as DPS and toluene in the final pure product propargite does not exceed 0.5%.
In an embodiment the unwanted impurities such as DPS and toluene in the final pure propartite is reduced to less than 0.5% using the present purification process. In an embodiment there is provided a process of reducing unwanted DPS impurity in propargite characterized in that a short-path vacuum distillation is carried out.
In an embodiment the present invention provides a method for reducing the unwanted high boiling and low boiling impurities preferably DPS impurity less than 0.5%, 4H impurity less than 5% or mixtures thereof.
In an embodiment the present invention provides highly pure Propiconazole and Propargite substantially free from unwanted DPS impurity and 4H impurity.
Moreover, the unwanted 4H impurity in final product propiconazole does not exceed 10%. In an embodiment the unwanted 4H impurity in final product propiconazole does not exceed 5%.
In an embodiment, the present invention provides highly pure propargite having purity of about 95% by weight and DPS impurity less than 0.5%.
In an embodiment, the present invention provides highly pure propargite having purity of about 95% by weight and DPS impurity less than 0.5%, purified using short path distillation.
In an embodiment, the present invention provides highly pure propargite having purity of about 95% by weight and DPS impurity less than 0.4%.
In an embodiment, the present invention provides highly pure propargite having purity of about 95% by weight and DPS impurity less than 0.3%.
In an embodiment, the present invention provides highly pure propargite having purity of about 95% by weight and DPS impurity less than 0.2%.
In an embodiment, the present invention provides highly pure propiconazole having purity of about 95% by weight and 4H impurity less than 5%.
In an embodiment, the present invention provides highly pure propiconazole having purity of about 95% by weight and 4H impurity less than 4%.
In an embodiment, the present invention provides highly pure propiconazole having purity of about 95% by weight and 4H impurity less than 3%.
In the present context, SPDU comprises of a feed tank, feed preheater and the short path distillation unit having internally mounted condenser and a rotor. Further, the unit is connected to vacuum system and the receivers to collect bottom and distillate. The short path condenser designed to minimize the distance between the evaporator flask and the condensation surface. A vacuum system, including a vacuum pump, creates a vacuum within the system, lowering the boiling points of the high boiler components in the mixture and reducing the risk of thermal degradation of the desired bottom. The condensed liquid collects in a receiver flask, allowing for the collection of impurities and purified components separately.
WFE includes a cylindrical or conical vessel designed for continuous evaporation of a liquid mixture. The liquid is introduced onto the inner surface of the vessel, forming a thin film, while a wiping mechanism, such as blades or rollers, ensures uniform distribution and renewal of the liquid film. The vessel is then heated to promote evaporation, and the evaporated vapor is promptly removed from the liquid film, minimizing residence time, and preventing thermal degradation. This configuration allows for efficient separation and purification of unwanted components/impurity formed during the process of preparation of agrochemical active ingredients with varying volatilities and difficult-to-remove impurities.
In the present context, the liquid mixture in the SPD and/or WFE is a crude propiconazole and/or propargite mixture. The mixture includes high boiling impurities which are subjected to SPD and/or WFE for obtaining pure propiconazole and/or propargite technical.
Both SPDU and WFE can be operated at much below 1.0 torr pressure due to their inherent design, and shorter distillation vapor path, thereby effectively removing the high boiling impurities at relatively lower temperature, without impacting the colour/ quality of the propiconazole and/or propargite product. The present process of purification is superior in purity and is novel and industrially advantageous.
According to one embodiment of the present invention the SPD and/or WFE is operated at following parameters:
1) SPD/ WFE Jacket Temp: 100° C to 130°C
2) Pressure: 0.1 to 1.0 Torr.
3) Feed Rate: As per equipment configuration.
4) Feed Temp: 70°C to 90°C
In an exemplary embodiment, the crude propargite technical feed (or liquid mixture) having average purity range of 85-92% comprising DPS and other high boiling impurities is subjected to SPD and/or WFE purification wherein DPS and other high boiling impurities are efficiently removed to enhance the purity of propargite technical to more than 92.0% and reduced impurity level. The crude technical, Propiconazole and/or Propargite can be prepared from conventionally known methods. For example, Propargite can be conventionally prepared by the process disclosed in patent applications such as, CN1830253 and CN103373943 and propiconazole can be conventionally prepared by the process disclosed in patent application CN105017232.
Since the present invention specifically relates to purification of Propiconazole and/or Propargite technical feed, the present invention may be integrated as a downstream technique after preparing Propiconazole and/or Propargite from known methods. Suitable techniques for synthesizing Propiconazole and/or Propargite are well known to a person skilled in the art.
Advantages of the present invention:
1. The present invention provides a novel process for purifying Propiconazole and/or Propargite that can safely and simply produce the desired product.
2. The present invention also offers a process/method for isolation of pure product with high yield and purity particularly Propiconazole and Propargite from other unwanted products that may occur in crude product.
3. Furthermore, the present invention provides highly pure Propiconazole and/or Propargite and the process is advantageous for production on an industrial scale.
4. The products, Propiconazole and/or Propargite purified by the process of the present invention contains substantially no impurity that can cause any issue while making the formulation.
5. The process of the present invention can be implemented on a large scale using low-cost materials, and is superior in economic efficiency, and is suitable for production on an industrial scale.
The present invention has numerous benefits over existing purification techniques such as batch type agitated reactors and shell and tube type evaporators (falling or rising film). It was therefore an object to find a simplified process that can be carried out safely and on an industrial scale advantageously and provides an active ingredient in high yield and high purity in agrochemically acceptable quality. The present invention involves an inventive feature that involves technical advance as compared to the existing knowledge or having economic significance or both and that makes the invention not obvious to a person skilled in the art. The present invention is carried out in shorter residence time, in fact of few seconds vs few hours in the conventional methods. Further, the operating temperature is substantially low. Due to low residence time and low operating temperature, the desired product degradation is minimized or completely avoided. Due to the precise operation and selection of parameters, purity of in the final product is substantially high. In fact, the product purity of more than 90%, or even more than 94% is achieved. The higher and consistent purity technical product helps to address instability issues in liquid agrochemical formulations and contributes to superior quality agrochemical formulations with fewer or no impurities. Furthermore, the present invention can be easily integrated with any existing technique for synthesizing Propiconazole and/or Propargite as a downstream purification step.
In an embodiment, the present invention provides an agrochemical composition comprising highly pure propartite having purity of about 90-95% by weight and DPS impurity less than 0.5% by weight, purified by short path distillation and an agrochemically acceptable excipient.
In an embodiment, the present invention provides an agrochemical composition comprising highly pure propiconazole having purity of about 95% by weight and 4H impurity less than 5% by weight, purified by short path distillation and an agrochemically acceptable excipient.
The following examples are for illustrative purposes only and are not intended, nor should they be interpreted, to limit the scope of the invention in any manner.
EXAMPLES:
Example 1:
Process for purification of propargite using SPDU
Multiple samples of crude propargite having average purity in the range of 85-92% by weight were used and was previously heated at 50- 60°C. The samples were subjected to SPDU purification under determined operating conditions in a continuous process and results are summarized in below tables.
Table 1: Propargite samples at different operating conditions

Operating conditions
Trial Jacket Pressure Jacket Temp Vacuum (Torr) Condenser Cooling media Feed Temp Feed rate
(Kg/cm2) (°C) (°C) (Kg/Hr)
1 1.3-1.6 124-126 0.1-0.2 26.8 73-80 17
2 1.5-1.6 127-129 0.1-0.2 26.3 82-85 16.8
3 1.4 125-126 0.1-0.2 26.4 80-86 15.68
4 1.2-1.6 122.127 0.1-0.2 27 77-79 18.6
5 1.4 124-127 0.1-0.2 28.2 79-84 17.9
6 1.4 123.127 0.15-0.2 25.5 79-82 18.31
7 1.5-1.7 124-126 0.3-0.5 26.8 75-80 15
8 1.5-1.6 127-129 0.3-0.5 26.3 75-80 16
9 1.5-1.6 125-130 0.3 -0.5 26.4 77-80 15.8

Feed
(% w/w)
Bottom – Product
(% w/w)

Trial PGT Toluene DPS PGT Toluene DPS

1 90.16 0.07 4.46 94.21 ND 0.22
2 88.83 0.03 6.57 94.54 ND 0.36
3 89.5 0.03 6.25 94.86 ND 0.29
4 89.45 0.03 4.75 93.61 ND 0.27
5 91.58 0.04 4.51 94.92 ND 0.29
6 90.96 0.03 4.01 94.58 ND 0.23
7 90.16 0.07 3 94.2 ND 0.46
8 90.16 0.07 3.5 94.1 ND 0.56
9 90.16 0.07 3.5 94 ND 0.44
*ND-Not detected.
Feed
(% w/w)
Distillate
(% w/w)

Trial PGT Toluene DPS PGT Toluene DPS

1 90.16 0.07 4.46 2.87 - 84.35
2 88.83 0.03 6.57 3.68 - 62.6
3 89.5 0.03 6.25 3.47 - 84.26
4 89.45 0.03 4.75 2.43 - 82.18
5 91.58 0.04 4.51 3.47 - 81.59
6 90.96 0.03 4.01 3.55 - 61.45
7 90.16 0.07 3 1 0.12 92.2
8 90.16 0.07 3.5 3.68 0.09 90
9 90.16 0.07 3.5 3.47 0.07 91
‘ – ‘ is NIL
As observed from above tables, high boiler impurities such as DPS and other low- boiling impurities (such as toluene) have been efficiently removed during purification using SPDU technique. The purity of PGT (propargite technical) reported with SPDU is about 94% by weight consistently and confirmed by multiple samples which were purified in accordance with the present invention with minimized or reduced impurity level thereby making propargite suitable for stable formulation without any degradation of the technical.
Table 2: Propargite (PGT) samples processed using WFE
Operating conditions-WFE
Trial Jacket Heating media Jacket Pressure (Kg/cm2) Jacket Temp (°C) Vacuum (Torr) Condenser Cooling media Feed Temp (°C) Feed rate (Kg/Hr)
1 LPS 1.5-1.6 135 0.3-0.5 26.3 75-80 16
2 LPS 1.5-1.6 140 0.3 -0.5 26.4 77-80 15.8
3 LPS 1.5-1.6 140 0.3 -0.5 26.4 77-80 15.8
4 LPS 1.5-1.6 140 0.3 -0.5 26.4 77-80 15.8
Feed
(% w/w)
Bottom – Product
(% w/w) Distillate
(% w/w)
Trial PGT Toluene DPS PGT Toluene DPS PGT Toluene DPS
1 89.65 0.13 2 91.8 0.08 1.86 1 0.11 89
2 89.65 0.13 2 91.5 0.06 1.71 2.5 0.15 89.2
3 89.65 0.13 2 91.5 0.07 1.5 2 0.12 90
4 89.65 0.13 2 91.5 0.05 1.2 1.8 0.14 88

Table 3: Propiconazole Samples processed using SPDU
Operating conditions
Trial Jacket Heating media Jacket Temp (°C) Vacuum (Torr) Condenser Cooling media Rotar RPM Feed Temp (°C) Feed rate (Kg/H r)
1 Oil 200 0.1 25-30 300 150 10-11
2 Oil 200 0.1 25-30 300 150 10-11
3 Oil 200 0.1 25-30 300 150 10-11

Feed
(% w/w)
Product
(% w/w)
Batch Number 1H 4H Toluene 1H 4H Toluene
1 85.1 13.4 1 93.31 5 0.3
2 85.1 15.3 1 94.14 4.2 0.4
3 85.1 13.4 1 94.6 4.7 0.37

It is evident from the above table that the present process for purification provides the desired propiconazole in high purity by removing or reducing unwanted high boiler impurities such as 4H impurity and other low boiling impurities (such as toluene). ,CLAIMS:We Claim:
1. A process for purification of an agrochemical active ingredient comprising
subjecting crude agrochemical active ingredient to short path distillation or wide film evaporation and
isolating pure agrochemical active ingredient having reduced unwanted impurities,
the agrochemical active ingredient is selected from propargite and propiconazole.
2. The process as claimed in claim 1 wherein the crude agrochemical active ingredient comprises propargite or propiconazole with unwanted high boiling and low boiling impurities such as DPS impurity upto 5-7%, 4H impurity upto 12-15%, toluene or mixtures thereof.
3. The process as claimed in claim 1 wherein crude agrochemical active ingredient is subjected to short path distillation at temperature in the range from 100°C to 250°C preferably in the range of 120°C to 150°C.
4. The process as claimed in claim 1 wherein the residence time for short path distillation is in the range from 2 to 30 seconds.
5. The process as claimed in claim 3 further comprises isolation of pure propargite having purity equal to or more than 95% by weight and unwanted DPS impurity reduced to less than 0.5%.
6. The process as claimed in claim 1 wherein the reduced unwanted impurities comprise high boiling and low boiling impurities such as DPS impurity less than 0.5%, 4H impurity less than 5%.
7. The process as claimed in claim 1 wherein the crude agrochemical active ingredient is selected from propargite and propiconazole subjected for short path distillation comprises propargite or propiconazole with high boiling and low boiling impurities such as DPS impurity upto 7%, 4H impurity upto 15%, toluene or mixtures thereof.
8. The process as claimed in claim 1 wherein isolating the agrochemical active ingredient comprises isolating highly pure propargite having purity of about 95% by weight and unwanted DPS impurity less than 0.5% or isolating highly pure propiconazole having purity of about 95% by weight and unwanted 4H impurity less than 5%.
9. Highly pure propargite having purity of about 95% by weight and unwanted DPS impurity less than 0.5% or highly pure propiconazole having purity of about 95% by weight and unwanted 4H impurity less than 5%.
10. An agrochemical composition comprising highly pure propargite having purity of about 95% by weight and unwanted DPS impurity less than 0.5% or highly pure propiconazole having purity of about 95% by weight and unwanted 4H impurity less than 5% as claimed in claim 9.

Dated this 12th day of March 2024
lndofil Industries Ltd
By their Agent & Attorney

(Nisha Austine)
of Khaitan & Co
Reg No IN/PA-1390