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 HYDROCHLORO FLUOROOLEFIN”

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

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

FIELD OF THE INVENTION
The present invention relates to a process for preparation of hydrochlorofluoroolefins. Also, the present invention provides a separation process of hydrochlorofluoroolefins using layer separation.

BACKGROUND OF THE INVENTION
Hydrofluorocarbon, widely used for refrigerants, heat transfer fluids, foam blowing agents, solvents, and aerosols, are being phased out and replaced by hydrofluoroolefins (HFO) and hydrochlorofluoroolefins (HCFO) due to their high global warming potential.
United States Patent No. 8921621 provides a process for preparation of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) by reacting 1,1,1,3,3-pentachloropropane (HCC-240fa) and hydrogen fluoride (HF) at a pressure 400 psig to 600 psig and further purified by partially condensing the product stream to obtain a condensate comprising HCFO-1233zd and finally separating the condensate.
United States Patent No. 8273928 provides a process for separation of fluoroolefin from a mixture comprising HF and fluoroolefin by first removing an azeotrope composition of HF and fluoroolefin as a first distillate, then condensing the first distillate to form to obtain fluoroolefins.
United States Patent No. 9227894 provides a process for preparation of 1-chloro-3,3,3-trifluoropropene (HFC-1233zd) by reacting 1,1,1,3,3-pentachloropropane (HCC-240fa) and hydrogen fluoride (HF) in presence of a catalyst at a high pressure, followed by multiple operations of distillation, re-distillation, phase separation by condensation, caustic scrubbing, drying, and re-distilling the organic components to provide purified 1233zd.
European Patent No. 3137183 provides a process for preparation of monochloro-trifluoropropene from an azeotrope or azeotrope like combination of monochloro-trifluoropropene and HF by distilling a reaction mixture to remove hydrogen chloride followed by multiple distillations including azeotropic distillation to isolate 1233zd.
United States Patent No. 9540296 provides a process for purification of 1233zd, by washing the crude HCFO-1233zd with water, followed by condensing the washed mixture and separating it into a lighter water layer and heavier HCFO-1233zd layer, and finally drying the HCFO-1233zd layer with a desiccant.
Most of the processes known for purification of 1233zd involves azeotropic distillation and layer separation by condensing the stream comprising 1233zd at low temperature range.
The present invention provides a process to obtain highly pure 1233zd by recirculating unconverted raw material or the excess into the decanter, where the organic and hydrogen fluoride layers are separated.

OBJECT OF THE INVENTION
The present invention provides a process for preparation and isolation of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) by recirculating unconverted raw material or the excess into the decanter.

SUMMARY OF THE INVENTION
In an aspect, the present invention provides a preparation and isolation of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), comprising the steps of:
a) heating 1,2-dichloroethane at a temperature of 200-600? to obtain a mixture comprising vinyl chloride;
b) reacting the mixture comprising vinyl chloride with carbon tetrachloride in presence of a catalyst to obtain a mixture comprising 1,1,1,3,3-pentachloropropane (240fa);
c) fluorinating the mixture comprising 1,1,1,3,3-pentachloropropane with hydrogen fluoride to obtain a mixture comprising 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd);
d) recirculating unconverted raw material selected from a group consisting of 1,2-dichloroethane, 1,1,1,3,3-pentachloropropane and carbon tetrachloride or a mixture thereof or the excess into the decanter containing the product stream comprising 1-chloro-3,3,3-trifluoropropene, to separate a hydrogen fluoride layer and an organic layer; and
e) isolating HCFO-1233zd from the organic layer.

DETAILS DECRIPTION OF THE INVENTION
As used herein, a mixture comprising 1-chloro-3,3,3-trifluoropropene further consists of hydrogen fluoride, hydrogen chloride, unreacted 240fa, intermediates like but not limited to 1,3-dichloro-3,3-difluoro-1propene and its isomers, 1,1-dichloro-3,3,3-trifluoropropane and its isomer, 1,2,3-trichloro-3,3-difluoropropane and its isomer, 1,1,3-trichloro-3,3-difluoropropane and its isomer, 1,1,3,3-tetrachloro-1fluoropropane and its isomers.
In another embodiment, the step of heating 1,2-dichloroethane at a temperature of 200-600? to obtain a mixture comprising vinyl chloride, is carried out in presence of carbon tetrachloride. In another embodiment, the conversion of 1,2-dichloroethane was maintained at 50-55% to avoid heavy tar formation.
In another embodiment, the step of reacting vinyl chloride with carbon tetrachloride is carried out in presence of ferric chloride/tributylphosphate/iron powder as complex as catalyst to obtain a mixture comprising 1,1,1,3,3-pentachloropropane.
In another embodiment, the step of fluorinating a feed comprising 240fa using a fluorinating agent in presence of catalyst in vapour phase to obtain a reaction mixture comprising 1-chloro-3,3,3-trifluoropropene.
The fluorination is carried out at a temperature of 200-300? and a pressure is of 0.1 to 20Kg/cm2. The step of fluorination is carried out using an anhydrous hydrogen fluoride in a vapour phase.
In another embodiment, the fluorination of 240fa using anhydrous hydrogen fluoride is carried out in tubular reactor having material of construction selected from Hastelloy, Inconel and Nickel or the like, that are resistant to corrosion.
In another embodiment, the process involves preheating 240fa and hydrogen fluoride prior to the reaction.
In another embodiment, the fluorination of 240fa with anhydrous hydrogen fluoride involve contacting 240fa and HF for 1-60 seconds.
As used herein, catalyst used in fluorination is selected from fluorinated chromia and fluorinated alumina. The catalyst used in the present invention are chromium oxyfluoride, chromium trifluoride, and aluminium trifluoride.
In an embodiment, 240fa is fluorinated using anhydrous hydrogen fluoride in presence of fluorinated chromia as a catalyst in a vapour phase to obtain a reaction mixture comprising 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride, hydrogen chloride, and unreacted 1,1,1,3,3-pentachloropropane.
In an embodiment, the fluorination is followed by dehydrohalogenation. The dehydrohalogenation can be dehydrofluorination and/or dehydrochlorination.
In another embodiment, the reaction mixture comprising 1-chloro-3,3,3-trifluoropropane, hydrogen fluoride, hydrogen chloride, and pentachloropropane is distilled for removal of hydrogen chloride, giving a top stream comprising hydrogen chloride and bottom mass comprising 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride and 1,1,1,3,3-pentachloropropane.
The top stream comprising hydrogen chloride is scrubbed in an alkali scrubber.
The distillation for removal of hydrogen chloride is carried out from 5 to 20 kg/cm2g pressure.
In an embodiment, the process involves adding a raw material selected from a group consisting of 1,2-dichloroethane, 1,1,1,3,3-pentachloropropane, and carbon tetrachloride or a mixture thereof to the mixture comprising 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride, and 1,1,1,3,3-pentachloropropane to separate two liquid phases, hydrogen fluoride phase and the organic phase.
The addition of solvent in the bottom mass composition is carried out at a temperature of 0 to 50?.
In an embodiment, the process involves adding a compound selected from a group consisting of trichloroethylene, tetrachloroethylene, tetrachloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane and 1,1,2-trichloroethane or a mixture thereof to the mixture comprising 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride and 1,1,1,3,3-pentachloropropane to separate two liquid phases, hydrogen fluoride phase and the organic phase.
The two liquid phases, obtained after addition of the raw material, are separated in liquid phase separator to obtain a top liquid phase comprising mainly of HF and an organic layer comprising 1-chloro-3,3,3-trifluoropropene.
In another embodiment, the organic layer comprising 1-chloro-3,3,3-trifluoropropene, and the raw material is distilled to obtain a top product stream comprising 1-chloro-3,3,3-trifluoropropene and a bottom stream comprising of R-240fa and other fluorinated intermediates like 1,3-dichloro-3,3-difluoro-1propene and its isomers, 1,1-dichloro-3,3,3-trifluoropropane and its isomer, 1,2,3-trichloro-3,3-difluoropropane and its isomer, 1,1,3-trichloro-3,3-difluoropropane and its isomer, 1,1,3,3-tetrachloro-1fluoropropane and its isomers. The bottom stream from this column is sent to another distillation column from where under fluorinated intermediates is taken from the top and sent back to the reactor. The bottom pentachloropropane can either be sent back to the layer separator or to the reactor.
In another embodiment, 1233zd is passed through a drying agent selected from a group consisting of sulfuric acid, molecular sieves, glycols or the like.
Unless stated to the contrary, any of the words “comprising”, “comprises” 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 completion of the reaction can be monitored by any one of chromatographic techniques such as thin layer chromatography (TLC), high pressure liquid chromatography (HPLC), ultra-pressure 5 liquid chromatography (UPLC), Gas chromatography (GC) and alike.
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 vinyl chloride.
1,2-Dichloroethane was thermally cracked in a tubular reactor at 400-550? to obtain vinyl chloride in presence of carbon tetrachloride (CTC) initiator. The conversion of 1,2-dichloroethane was maintained at 50-55% to avoid heavy tar formation.
Example 2: Preparation of 1,1,1,3,3-pentachloropropane (240fa)
An autoclave reactor was charged with ferric chloride/tributylphosphate/Iron powder as a catalyst complex to which carbon tetrachloride was added 2-5 times the mass of the complex. The temperature of the reactor was raised to 90oC and then both the feed namely carbon tetrachloride and vinyl chloride were fed. The reactor pressure was maintained around 2-4 kg/cm2g. The crude product was distilled to obtain 1,1,1,3,3-pentachloropropane. Conversion: 96.9%; Selectivity: 92.8%.
Example 3: Preparation of trans-1-chloro-3,3,3-trifluoropropene (trans-1233zd)
1,1,1,3,3-Pentachloropropane (240fa) and anhydrous hydrogen fluoride were preheated at a temperature of 130?, mixed and reacted in a tubular reactor at a temperature of 250? and at a vapour pressure of 10Kg/cm2 in presence of a fluorinated chromia catalyst. The reactor outlet was taken to a distillation column and from a top stream comprising hydrogen chloride was removed and added 240fa in the distillation bottom mass. The distillation mass was separated in the two layers in a liquid phase separator at room temperature in a decanter. The top layer comprising mainly of hydrogen fluoride and bottom layer comprising of mainly of 1233zd, 240fa. The bottom organic layer was washed with water followed by caustic solution. The bottom organic layer was then passed through diethyl glycol and sent to a distillation column to remove lighter organics and bottom mass was further distilled to isolate R-1233zd (Trans) as top stream and 240fa along with intermediate remain in the distillation bottom which was recycled back into the reactor or the decanter. The top layer comprising mainly of hydrogen fluoride was taken in another distillation column from where hydrogen fluoride along with organics are recycled back into reactor and at the bottom moisture rich hydrogen fluoride is purged out of the system. Analysis: Selectivity: 80%; Conversion: 99%; Trans-1233zd (GC Purity): 99.5%.
Example 4: Process for separation of AHF from crude R-1233zd.
A synthetic mixture containing anhydrous hydrogen fluoride (676 g), R-1233zd crude (462 g), and 1,1,1,3,3-pentachloropropane (462 g) was taken in a stainless-steel pipe with provision for sampling at different points. The synthetic mixture was mixed and then allowed to remain in vertical position overnight. The samples were taken from top and bottom. The bottom layer was predominantly organic with less than 1 % anhydrous hydrogen fluoride and the top layer consists of predominantly hydrogen fluoride with less than 5% organic. More than 97% organic was recovered as bottom layer. Analysis:
Before Layer Separation:
Input: AHF: 676 g, Crude R-1233zd : 462 g, Pure R-240fa : 462 g (added)
After Layer separation:
Bottom organic layer analysis:
Bottom layer quantity (g) AHF in bottom layer (%) Organic in bottom layer (%) AHF in bottom layer (g) Organic in bottom layer (g)
913.5g 0.93% 99.07% 8.5g 904.5g

Top AHF layer analysis:
Top layer quantity AHF in top layer (%) Organic in Top layer (%) AHF in top layer (g) Organic in top layer (g)
694.13g 96.1% 3.9% 667.03g 27.1g

Example 5:
The process described in Example 3-4 were repeated by adding 1,2-dichloroethane and below results were obtained:
Before Layer Separation:
Input: AHF: 700 g, Crude R-1233zd: 400 g, Pure 1,2-dichloroethane: 400 g (added)
After Layer separation:
Bottom organic layer analysis:
Bottom layer quantity (g) HF in bottom layer (%) Organic in bottom layer (%) AHF in bottom layer (g) Organic in bottom layer (g)
0.91% 99.2% 8.2g 905.8g

Top AHF layer analysis:
Top layer quantity AHF in top layer (%) Organic in Top layer (%) AHF in top layer (g) Organic in top layer (g)
97.5% 2.4% 700.03g 25.1g

Example 6:
The process described in Example 3-4 were repeated by adding carbon tetrachloride and below results were obtained:
Before Layer Separation:
Input: AHF: 700 g, Crude R-1233zd: 400 g, Pure carbon tetrachloride: 400 g (added)
After Layer separation:
Bottom organic layer analysis:
Bottom layer quantity (g) HF in bottom layer (%) Organic in bottom layer (%) AHF in bottom layer (g) Organic in bottom layer (g)
0.97% 98.2% 9.2g 900.8g

Top AHF layer analysis:
Top layer quantity AHF in top layer (%) Organic in Top layer (%) AHF in top layer (g) Organic in top layer (g)
96.5% 2.8% 698.03g 27.1g

The above tables clearly show that separation of anhydrous hydrogen fluoride can be easily done from crude 1233zd by adding raw material selected from the group consisting of 240fa, 1,2-dichloroethane and carbon tetrachloride in the crude 1233zd and separating the organic layers to obtain the bottom layer comprising mainly of organic and top layer comprising mainly of hydrogen fluoride layer.
Later, R-1233zd (Trans) can be easily separated from this organic layer by distillation.
Example 7: The process as disclosed in GB2313118A for the preparation of 1233zd was repeated to obtain a mixture comprising 1233zd and hydrogen fluoride, which was separated to isolate 1233zd by following the process delineated in above Examples 4-6.
,CLAIMS:WE CLAIM
1. A process for preparation and isolation of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), comprising the steps of:
a) heating 1,2-dichloroethane at a temperature of 200-600? to obtain a mixture comprising vinyl chloride;
b) reacting the mixture comprising vinyl chloride with carbon tetrachloride in presence of a catalyst to obtain a mixture comprising 1,1,1,3,3-pentachloropropane (240fa);
c) fluorinating the mixture comprising 1,1,1,3,3-pentachloropropane with hydrogen fluoride to obtain a mixture comprising 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd);
d) recirculating unconverted raw material selected from a group consisting of 1,2-dichloroethane, 1,1,1,3,3-pentachloropropane and carbon tetrachloride or a mixture thereof or the excess into the decanter containing the product stream comprising 1-chloro-3,3,3-trifluoropropene, to separate a hydrogen fluoride layer and an organic layer; and
e) isolating HCFO-1233zd from the organic layer.
2. The process as claimed in claim 1, wherein a mixture comprising 1-chloro-3,3,3-trifluoropropene further consists of hydrogen fluoride, hydrogen chloride, unreacted 240fa, 1,3-dichloro-3,3-difluoro-1propene and its isomers, 1,1-dichloro-3,3,3-trifluoropropane and its isomer, 1,2,3-trichloro-3,3-difluoropropane and its isomer, 1,1,3-trichloro-3,3-difluoropropane and its isomer and 1,1,3,3-tetrachloro-1-fluoropropane and its isomers.
3. The process as claimed in claim 1, wherein the step of reacting vinyl chloride with carbon tetrachloride is carried out in presence of ferric chloride/tributylphosphate/iron powder complex as catalyst.
4. The process as claimed in claim 1, wherein the fluorination is carried out at a temperature of 200-300? and a pressure is of 0.1 to 20Kg/cm2.
5. The process as claimed in claim 1, wherein the fluorination is carried out using an anhydrous hydrogen fluoride in a vapour phase.
6. The process as claimed in claim 1, wherein the catalyst used in fluorination is selected from fluorinated chromia and fluorinated alumina.
7. The process as claimed in claim 1, wherein the fluorination is followed by dehydrohalogenation.
8. The process as claimed in claim 1, wherein the reaction mixture comprising 1-chloro-3,3,3-trifluoropropane, hydrogen fluoride, hydrogen chloride, and pentachloropropane is distilled for removal of hydrogen chloride, giving a top stream comprising hydrogen chloride and bottom mass comprising 1-chloro-3,3,3-trifluoropropene, hydrogen fluoride and 1,1,1,3,3-pentachloropropane.
9. The process as claimed in claim 1, wherein the conversion of 1,2-dichloroethane is maintained at 50-55%.

Dated this 26th day of September 2022.