Method for separating and recovering 2,3,3,3-tetrafluoropropene and hydrofluoric acid

Patent metadata

Field	Value
Publication number	US-2016130200-A1
Application number	US-201614995493-A
Country	US
Kind code	A1
Filing date	Jan 14, 2016
Priority date	Jul 8, 2011
Publication date	May 12, 2016
Grant date	—

Abstract

The present invention relates to a method for separating a composition containing 2,3,3,3-tetrafluoropropene and hydrofluoric acid, and for recovering the thus-separated 2,3,3,3-tetrafluoropropene and hydrofluoric acid. The invention also relates to a method for manufacturing and purifying 2,3,3,3-tetrafluoropropene using a hydrofluorination reaction of the saturated or unsaturated compound having three carbon atoms and including at least one chlorine atom in the presence of a fluorination catalyst.

First claim

1 . A process for the separation and recovery of 2,3,3,3-tetrafluoropropene and HF from a composition comprising 2,3,3,3-tetrafluoropropene and HF, characterized in that it comprises a stage of cooling said composition in the presence of an added amount of at least one compound (C1) chosen from chlorocarbons, hydrochlorocarbons, hydrochlorofluorocarbons, optionally fluorinated alcohols, optionally fluorinated ethers, ketones, esters, polyols and hydrofluorinated ethers in order to give an upper phase rich in HF and a lower organic phase rich in HFO-1234yf and compound C1.

2 . The process as claimed in claim 1 characterized in that the 2,3,3,3-tetrafluoropropene/HF molar ratio is between 0.5 and 2.5, preferably between 1.1 and 2.1.

3 . The process as claimed in claim 1 or 2 , characterized in that the amount of compound C1 to be added represents from 5% to 95% by weight, with respect to the HFO-1234yf/HF mixture, preferably from 10% to 80% by weight, with respect to the HFO-1234yf/HF mixture.

4 . The process as claimed in any one of the preceding claims, characterized in that the cooling temperature is between −20 and 40° C. and preferably between −5 and 35° C.

5 . The process as claimed in any one of the preceding claims, characterized in that the composition comprising 2,3,3,3-tetrafluoropropene and HF originates from a hydrofluorination reaction on at least one saturated or unsaturated hydrocarbon compound having three carbon atoms and comprising at least one chlorine atom in the presence of a fluorination catalyst.

6 . The process as claimed in claim 5 , characterized in that the saturated or unsaturated hydrocarbon compound having three carbon atoms is chosen from 1,1,1,2,3-pentachloropropane, 1,1,2,3-tetrachloropropene and 2-chloro-3,3,3-trifluoropropene.

7 . The process as claimed in claim 5 or 6 , characterized in that the stream resulting from the hydrofluorination stage is subjected to a stage of removal of HCl before the cooling stage.

8 . The process as claimed in any one of the preceding claims, characterized in that the compound C1 is chosen from 1,1,1,2,3-pentachloropropane, 1,1,2,3-tetrachloro-1-fluoropropane, 1,2-dichloro-3,3,3-trifluoropropane, 1,1,2,3-tetrachloropropene and 2-chloro-3,3,3-trifluoropropene.

9 . The process as claimed in any one of the preceding claims, characterized in that the compound C1 is chosen from alcohols ROH, ketones RCOR′, esters RCOOR′, with R and R′, which are identical or different, each representing an alkyl group of 1 to 5 carbon atoms, and ethers ROR′, with R and R′, which are identical or different, each representing an alkyl group of 1 to 7 carbon atoms.

10 . The process as claimed in any one of claims 5 to 8 , characterized in that the compound C1 is the same as that which has reacted with HF in the hydrofluorination stage.

11 . The process as claimed in any one of claims 5 to 10 characterized in that the part enriched in HF after the cooling stage is recycled to the hydrofluorination stage.

12 . The process as claimed in any one of the preceding claims, characterized in that the 2,3,3,3-tetrafluoropropene is separated from the organic part enriched in 2,3,3,3-tetrafluoropropene after the cooling stage.

13 . The process as claimed in claim 12 , characterized in that the organic part, after separation of the 2,3,3,3-tetrafluoropropene is recycled to the cooling stage and/or to the reaction stage.

14 . A process for the manufacture of 2,3,3,3-tetrafluoropropene, comprising (i) at least one reaction stage during which 1,1,1,2,3-pentachloropropane reacts in the gas phase with the HF in the presence of a fluorination catalyst to give a stream comprising 2,3,3,3-tetrafluoropropene and its intermediates, HCl and excess HF; (ii) a stage of removal of HCl from the stream exiting from stage (i); (iii) a stage of cooling in the presence of the addition of 1,1,1,2,3-pentachloropropane as claimed in any one of claims 1 to 4 to give an upper phase rich in HF and a lower organic phase rich in 2,3,3,3-tetrafluoropropene and comprising 1,1,1,2,3-pentachloropropane; (iv) a stage of separation of the 2,3,3,3-tetrafluoropropene from the lower phase and optionally recycling the 1,1,1,2,3-pentachloropropane to the cooling stage (iii) and/or to the reaction stage (i); (v) a stage of purification of the 2,3,3,3-tetrafluoropropene and (vi) optionally recycling of the upper phase rich in HF to stage (i).

15 . The process as claimed in claim 14 , characterized in that it comprises a stage of distillation of HF before the stage of removal of HCl.

Assignees

• Arkema France

Inventors

• Deur-Bert Dominique
• Collier Bertrand

Classifications

• C07C17/25

  by splitting-off hydrogen halides from halogenated hydrocarbons · CPC title

• C07C17/35

  by reactions not affecting the number of carbon or of halogen atoms in the reaction · CPC title

• C07C17/38

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C17/42 Primary

  Use of additives, e.g. for stabilisation · CPC title

• C07C17/383

  by distillation · CPC title