# US 10,479,746 B2 · Method for producing and purifying 2,3,3,3-tetrafluoro-1-propene

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- Number: US 10,479,746 B2
- Document ID: US10479746B2
- Status: Granted
- Kind: B2
- Application number: 16/064,013
- Filed: 2016-12-14
- Published: 2019-01-03
- Granted: 2019-11-19
- Earliest claimed: 2015-12-23
- Assignees: Arkema France
- Applicants: Arkema France
- Inventors: Abdelatif Baba-Ahmed; Bertrand Collier; Dominique Deur-Bert; Laurent Wendlinger
- Web page: https://patentgrep.com/patent/US10479746B2

## CPC

- C07C 17/386: with auxiliary compounds
- B01D 3/40: Extractive distillation
- C07C 17/25: by splitting-off hydrogen halides from halogenated hydrocarbons
- C09K 5/045: {containing only fluorine as halogen}
- C09K 2205/126: Unsaturated fluorinated hydrocarbons
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

The present invention concerns a method for purifying 2,3,3,3-tetrafluoro-1-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-1-propene and at least one of the compounds chosen from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115), and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) said method comprising the steps consisting of: a) bringing said first composition into contact with at least one organic extractant in order to form a second composition; b) extractive distillation of said second composition in order to form (i) a third composition comprising said organic extractant and said at least one of the compounds chosen from the group consisting of 1,1-difluoroethane (152a) chloropentafluoroethane (115), and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); and ii) a stream comprising 2,3,3,3-tetrafluoro-1-propene. The invention also concerns a method for producing and purifying 2,3,3,3-tetrafluoro-1-propene.

## Claims

### Claim 1

A process for purifying 2,3,3,3-tetrafluoro-1-propene (1234yf) using a first composition comprising 2,3,3,3-tetrafluoro-1-propene and at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E), said process comprising:
a) placing said first composition in contact with at least one organic extracting agent to form a second composition;
b) distilling said second composition by extractive distillation to form:
i) a third composition comprising said organic extracting agent and said at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E); and
ii) a stream comprising 2,3,3,3-tetrafluoro-1-propene; and
c) recovering and separating said third composition to form a stream comprising said organic extracting agent and a stream comprising said at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E).

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein the first composition comprises 2,3,3,3-tetrafluoro-1-propene, trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of 1,1-difluoroethane (152a) and chloropentafluoroethane (115) and the third composition comprises said organic extracting agent, trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of 1,1-difluoroethane (152a) and chloropentafluoroethane (115); and wherein step c) comprises recovering said third composition and separating between, on the one hand, said organic extracting agent and, on the other hand, trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of 1,1-difluoroethane (152a) and chloropentafluoroethane (115).

### Claim 3 (depends on 1)

The process as claimed in claim 1, wherein said organic extracting agent comprises a solvent selected from the group consisting of hydrocarbon, halohydrocarbon, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide and heterocycle; or said organic extracting agent comprises difluorodiethylsilane, triethylfluorosilane or perfluorobutanoic acid.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein the boiling point of said organic extracting agent is between 10 and 150° C.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein said organic extracting agent has a separation factor S1,2 of greater than or equal to 1.1, said separation factor being calculated by the formula S1,2=(γ1,S*P1)/(γ2,S*P2) wherein
γ1,S represents the activity coefficient of 2,3,3,3-tetrafluoro-1-propene in said organic extracting agent at infinite dilution;
P1 represents the saturating vapor pressure of 2,3,3,3-tetrafluoro-1-propene;
γ2,S represents the activity coefficient of said at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) in said organic extracting agent at infinite dilution; and
P2 represents the saturating vapor pressure of said at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E).

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein said organic extracting agent has an absorption capacity C2,S of greater than or equal to 0.20, said absorption capacity being calculated by the formula C2,S=1/(γ2,S) wherein γ2,S represents the activity coefficient of said at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) in said organic extracting agent at infinite dilution.

### Claim 7 (depends on 1)

The process as claimed in claim 1, wherein said first composition comprises an azeotropic or quasi-azeotropic composition comprising 2,3,3,3-tetrafluoro-1-propene, trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of 1,1-difluoroethane (152a) and chloropentafluoroethane (115).

### Claim 8 (depends on 1)

The process as claimed in claim 1, wherein said organic extracting agent is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, ethoxyethene, dimethoxymethane, n-propylamine, methyl t-butyl ether, diethylamine, propanone, methyl acetate, isobutanal, tetrahydrofuran, isopropyl formate, diisopropyl ether, 2-ethoxy-2-methylpropane, ethyl acetate, butanone, diethoxymethane, isopropyl acetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 3-pentanone, 1,1-diethoxyethane, 2-pentanone, trimethoxymethane, n-pentylamine, 1,3-dioxane, 3,3-dimethyl-2-butanone, sec-butyl acetate, 4-methyl-2-pentanone, 1,2-diaminoethane, 1-methoxy2-propanol, diethyl carbonate, n-butyl acetate, 1-ethoxy-2-propanol and hexanal.

### Claim 9 (depends on 1)

The process as claimed in claim 1, further comprising recovering the stream comprising 2,3,3,3-tetrafluoro-1-propene formed in step b) and freeing said stream of at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E).

### Claim 10 (depends on 1)

The process as claimed in claim 1, further comprising, prior to step a):
i′) use of a composition comprising 2,3,3,3-tetrafluoro-1-propene, impurities with a boiling point below the boiling point of 2,3,3,3-tetrafluoro-1-propene, and at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E), and optionally heavy impurities;
ii′) distilling said composition from step i) to remove, at the top of the column, impurities with a boiling point below the boiling point of 2,3,3,3-tetrafluoro-1-propene and to form a first stream comprising 2,3,3,3-tetrafluoro-1-propene and at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E), and optionally heavy impurities, recovered at the bottom of the distillation column; and
iii′) optionally, distillating said first stream recovered at the bottom of the distillation column in step ii′) to recover, at the top of the column, a second stream comprising 2,3,3,3-tetrafluoro-1-propene and at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E), and, at the bottom of the distillation column, a stream comprising the heavy impurities;
wherein said first stream recovered in step ii′) or said second stream recovered in step iii′) corresponds to said first composition used in step a).

### Claim 11 (depends on 1)

A process for producing and purifying 2,3,3,3-tetrafluoro-1-propene, comprising:
A) fluorination in the presence of a catalyst for a compound of formula (I) CX(Y)2-CX(Y)m—CHmXY wherein X and Y independently represent a hydrogen, fluorine or chlorine atom and m=0 or 1; and/or fluorination in the presence of a catalyst for a compound of formula (CXnY3-n)CHpX1-pCHmX2-m (II) in which X is, independently of each other, Cl, F, I or Br; Y is, independently of each other, H, Cl, F, I or Br; n is 1, 2 or 3; and m is 0, 1 or 2; and p is 0 or 1;
B) recovering a stream comprising 2,3,3,3-tetrafluoro-1-propene and at least one compound selected from the group consisting of 1,1-difluoroethane (152a), chloropentafluoroethane (115) and trans-1,3,3,3-tetrafluoro-1-propene (1234ze-E);
C) implementing the process as claimed in claim 1 using the stream recovered in step B).