DESC:FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

“PROCESS FOR PREPARATION OF ALKALI AND ALKALINE EARTH METAL SALTS OF HALOALKYL CARBOXYLIC ACID”

SRF LIMITED, AN INDIAN COMPANY,
SECTOR 45, BLOCK-C, UNICREST BUILDING,
GURGAON – 122003,
HARYANA (INDIA)

The following specification particular describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention provides a process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid using mild and easily available agents.

BACKGROUND OF THE INVENTION
The present invention provides a process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid which are important intermediates for the preparation of different pharmaceutical and agrochemical products.
A few methods are known for the preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid.
U.S. Pat. No. 4,760,177 discloses a process for preparation of alkali metal salts of trifluoroacetic acid by reacting trifluoro acetic acid with alkali metal carbonate in presence of alcohol. The use of alcohol poses challenges in isolation of the final salt.
The present invention relates to a cost effective and robust process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid.

OBJECT OF THE INVENTION
The present invention provides a commercially viable process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid using mild and easily available agents with effective recovery and recycle of solvents.

SUMMARY OF THE INVENTION
The present invention provides a process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid, comprising the step of reacting haloalkyl carboxylic acid with an agent in the presence of an organic solvent to obtain alkali and alkaline earth metal salts of haloalkyl carboxylic acid.

DESCRIPTION OF THE INVENTION
In an embodiment, the present invention provides a process for preparation of alkali and alkaline earth metal salt of haloalkyl carboxylic acid, comprising the step of reacting haloalkyl carboxylic acid with an agent in the presence of an organic solvent to obtain alkali and alkaline earth metal salt of haloalkyl carboxylic acid.
In an embodiment, the reaction of haloalkyl carboxylic acid is carried out using an agent in the presence of an organic solvent to obtain alkali and alkaline earth metal salt of haloalkyl carboxylic acid.
As used herein, the agent is at least one compound selected from the group consisting of alkali metal hydroxides, alkaline earth hydroxides, metal carbonates and metal oxides.
The preferred alkali and alkaline earth metals can be selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, lithium carbonate, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, magnesium carbonate and ammonium carbonate or mixture thereof.
As used herein, the organic solvent is selected from a group consisting of toluene, chlorobenzene, o-dichlorobenzene, cyclohexane, benzotrifluoride, xylene or a mixture thereof.
In another embodiment, the mole ratio of the agent w.r.t haloalkyl carboxylic acid is ranging from about 0.90 to 1.3 and most preferably 0.97.
In another embodiment, the mole ratio of the organic solvent to haloalkyl carboxylic acid is from about 4.0 to 10.0 and more preferably 5.0.
In another embodiment, the process of the present invention provides an efficient recycling and recovery of solvents.
In another embodiment, the reaction of haloalkyl carboxylic acid with alkaline agent is carried out at a temperature in the range from 100 to 160?.
In a specific embodiment, the process for the preparation of the alkali and alkaline earth metal salt of haloalkyl carboxylic acid involves reaction of haloalkyl carboxylic acid and solvent to form a reaction mixture and then alkaline reagent introduced into the reaction mixture as such or in solution form. After complete addition of a reagent to the reaction mixture, moisture was distilled out from the reaction mass at a temperature between 100-150? under atmospheric pressure. Thereafter, gradually cool down the reaction mass to 20? and maintained the temperature for 1 hour. Then, filtered the resultant slurry mass under nitrogen pressure and washed the obtained wet cake with hexane and dried to obtain desired product.
In the present invention for the preparation of alkali and alkaline earth metal salt of haloalkyl carboxylic acid offers following advantages over the known methods:
1. It reduces the number of operations of the industrial scale thereby making it cost effective and commercially viable process.
2. The process of the present invention provides efficient recycling and recovery of solvents.
3. The process of present invention is simple and safe at commercial scale.
4. The process of present invention is highly industrial favourable as it exhibits a high yield of the product.
In another embodiment, the present invention provides a yield of greater than 95.0% for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid.
In another embodiment, the present invention provides a process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid having assay greater than 98.0%.
In another embodiment, the alkali and alkaline earth metal salts of haloalkyl carboxylic acid are obtained with a yield selected in the range of 95 to 99%.
In another embodiment, the alkali and alkaline earth metal salts of haloalkyl carboxylic acid are obtained with an assay selected in the range of 98% to 99.5%.
In another embodiment, haloalkyl carboxylic acid refers to difluoroacetic acid, dichloroacetic acid, trifluoroacetic acid, trichloroacetic acid, pentafluoropropionic acid, chloro-difluoroacetic acid and a like.
The haloalkyl carboxylic acid used in the present invention may be prepared by any method known in the literature or may be obtained commercially.
The compounds of the invention are isolated by any method known in the art, for example, chemical separation, extraction, acid-base neutralization, distillation, evaporation, column chromatography and filtration or a mixture thereof.
The completion of the reaction may be monitored by any one of chromatographic techniques such as thin layer chromatography (TLC), high pressure liquid chromatography (HPLC), ultra-pressure liquid chromatography (UPLC), Gas chromatography (GC), liquid chromatography (LC) or acid-base titration and alike.
The reagents used in the above process are obtained commercially.
Unless stated to the contrary, any of the words “comprising”, “comprises” and includes mean “including without limitation” and shall not be construed to limit any general statement that it follows to the specific or similar items or matters immediately following it.
Embodiments of the invention are not mutually exclusive, but may be implemented in various combinations. The described embodiments of the invention and the disclosed examples are given for the purpose of illustration rather than limitation of the invention as set forth in the appended claims.
The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention.

EXAMPLES
Example 1: Preparation of potassium trifluoroacetate
Trifluoro acetic acid (200 g, 1.75 mole) and xylene (1000 g, 9.42 mole) were added into the reactor to form a reaction mixture. Aqueous potassium hydroxide (KOH) (40%, 281.7 g, 2.01 mole) was added into the reaction mixture at a temperature < 50?. After complete addition of KOH, water and unreacted trifluoroacetic acid were distilled out from the reaction mass at a temperature between 100-150? under atmospheric pressure by using dean stark. Thereafter, gradually cooled down the reaction mass to 20? and maintained the reaction mass at same temperature for an additional an hour. Then filtered the resultant slurry mass under nitrogen pressure and washed the wet cake with hexane (2*200 g, 4.64 mole). Dried the wet cake to get titled compound.
Yield: 98%; Assay: 94.0 wt%

Example 2: Preparation of potassium trifluoroacetate
Trifluoro acetic acid (100 g, 0.87 mole) and xylene (700 g, 6.60 mole) were added into the reactor to form a reaction mixture. Aqueous KOH (40%, 110 g, 0.78 mole) was added into the reaction mixture at a temperature < 50?. After complete addition of KOH, water and unreacted trifluoroacetic acid were distilled out from the reaction mass at a temperature between 100-150? and at an atmospheric pressure by using dean stark. Thereafter, gradually cooled down the reaction mass to 20? and maintained the temperature for an hour. Then filtered the resultant slurry mass under nitrogen pressure and washed the wet cake with hexane (2*100 g, 2.32 mole) and dried to get titled compound.
Yield: 85%; Assay: 98.5 wt%
Example 3: Preparation of potassium salt of 2,2,3,3,3-pentafluoro propionic acid
2,2,3,3,3-Pentafluoro propionic acid (50 g, 0.30 mole) and toluene (250 g, 2.72 mole) were added into the reactor to form a reaction mixture. Aqueous KOH (40%, 40 g, 0.28 mole) was added into the reaction mixture at a temperature < 70?. After complete addition of aqueous KOH solution, water and unreacted 2,2,3,3,3-pentafluoro propionic acid were distilled out from the reaction mass at a temperature between 100-150? under atmospheric pressure by using dean stark. Thereafter, gradually cooled down the reaction mass to 20? and maintained at the same temperature for an additional an hour. Then filtered the resultant slurry mass under nitrogen pressure and washed the wet cake with hexane (2*50 g, 1.16 mole). Dried to get titled compound.
Yield: 90%; Assay: 98.0 wt%
Example 4: Preparation of sodium salt of 2-chloro-2,2-difluoroacetic acid
2-Chloro-2,2-difluoro acetic acid (50 g, 0.34 mole) and xylene (500 g, 4.72 mole) were added into the reactor to form a reaction mixture. Aqueous sodium hydroxide (NaOH) (20%, 67 g, 0.33 mole) was added into the reaction mixture at a temperature < 70?. After complete addition of aqueous NaOH solution, water and unreacted 2-chloro-2,2-difluoro acetic acid were distilled out from the reaction mass at a temperature between 100-160? and at an atmospheric pressure by using dean stark. Thereafter, gradually cooled down the reaction mass to 20? and maintained the reaction mass at the same temperature for an additional an hour. Then filtered the resultant slurry mass under nitrogen pressure and washed the wet cake with hexane (2*50 g, 1.16 mole). Then dried to get titled compound. Yield: 91%; Assay: 96.0 wt%
Example 5: Preparation of calcium trifluoroacetate
Trifluoro acetic acid (100 g, 0.87 mole) and xylene (500 g, 4.72 mole) were added into the reactor to form a reaction mixture. Calcium hydroxide (Ca(OH)2) (31.80 g, 0.43 mole) was added into the reaction mixture at a temperature < 50?. After complete addition of Ca(OH)2, water and unreacted trifluoroacetic acid were distilled out from the reaction mass at a temperature between 100-150? and at an atmospheric pressure by using dean stark. Thereafter, gradually cooled down the reaction mass to 20? and maintained the temperature for an additional an hour. Then filtered the resultant slurry mass under nitrogen pressure and washed the wet cake with hexane (2*100 g, 2.32 mole). Dried to get titled compound. Yield: 97%; Assay: 98.0 wt%
,CLAIMS:WE CLAIM:
1. A process for preparation of alkali and alkaline earth metal salts of haloalkyl carboxylic acid, comprising the step of reacting haloalkyl carboxylic acid with an agent in the presence of an organic solvent to obtain alkali and alkaline earth metal salts of haloalkyl carboxylic acid.
2. The process as claimed in claim 1, wherein the agents used is selected from the group consisting of alkali metal hydroxides, alkaline earth hydroxides, metal carbonates and metal oxides.
3. The process as claimed in claim 1, wherein the alkali and alkaline earth metal hydroxides are selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, lithium carbonate, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, magnesium carbonate and ammonium carbonate.
4. The process as claimed in claim 1, wherein the organic solvent is selected from a group consisting of toluene, chlorobenzene, o-dichlorobenzene, cyclohexane, benzotrifluoride, xylene or a mixture thereof.
5. The process as claimed in claim 1, wherein the reaction is carried out at a temperature in the range from 30 to 70?.
6. The process as claimed in claim 1, wherein the mole ratio of the agent w.r.t haloalkyl carboxylic acid is selected in the range of0.90 to 1.3.
7. The process as claimed in claim 1, wherein the solvent is recycled and reused.
8. The process as claimed in claim 1, wherein the alkali and alkaline earth metal salts of haloalkyl carboxylic acid are obtained with a yield selected in the range of 95 to 99%.
9. The process as claimed in claim 1, wherein the alkali and alkaline earth metal salts of haloalkyl carboxylic acid are obtained with an assay selected in the range of 98% to 99%.
10. The process as claimed in claim 1, wherein haloalkyl carboxylic acid is selected from a group consisting of difluoroacetic acid, dichloroacetic acid, trifluoroacetic acid, trichloroacetic acid, pentafluoropropionic acid and chloro-difluoroacetic acid.

Dated this 29th day of September 2023.