# US 2021/0214293 A1 · Process for purification of olefin feed comprising 1234yf

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- Number: US 2021/0214293 A1
- Document ID: US20210214293A1
- Status: Published application
- Kind: A1
- Application number: 17/054,863
- Filed: 2019-05-13
- Published: 2021-07-15
- Earliest claimed: 2018-05-16
- Assignees: SRF Limited
- Applicants: Srf Limited
- Inventors: Jose GEORGE; Sunil RAJ; Ambuj Kumar MISHRA; Anurag KATIYAR; Anurag JAIN; Sudip MAITY
- Web page: https://patentgrep.com/patent/US20210214293A1

## CPC

- C07C 17/386: with auxiliary compounds
- C07C 17/38: Separation; Purification; Stabilisation; Use of additives
- C07C 17/383: by distillation
- C07C 17/389: by adsorption on solids
- C07C 17/266: of hydrocarbons and halogenated hydrocarbons
- C07C 17/269: of only halogenated hydrocarbons
- C07C 17/275: of hydrocarbons and halogenated hydrocarbons
- C07C 17/278: of only halogenated hydrocarbons
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The present invention relates to a process for purifying olefin feed comprising R-5 1234yf, R-40, R-134a, R-134, R-1225zc, and OFCB, comprising the step of separating different ternary and binary azeotrope compositions comprising 1234yf. The olefin feed is obtained from the pyrolysis of tetrafluoroethylene/chlorodifluoromethane with chloromethane/methane, optionally in presence of initiator.

## Claims

### Claim 1

A process for purification of R-1234yf feed comprising R-1234yf, R-40, R-134a, R-134, R-1225zc, and OFCB, said process comprising a step of separating a ternary azeotrope composition “A” comprising about 52 mole % to about 62 mole % of R-1234yf, about 25 mole % to about 34 mole % of R-40 and about 2 mole % to about 25 mole % of R-134a R-1234yf, R-40 and R-134a.

### Claim 2

A process for purification of R-1234yf feed comprising R-1234yf, R-40, R-134a, R-134, R-1225zc, and OFCB, said process comprising a step of separating a binary azeotrope composition “B” comprising about 10 mole % to about 35 mole % of R-134a and about 65 mole % to about 90 mole % of 1234yf R-1234yf and R-134a.

### Claim 3 (depends on 1)

The A process for purification of R-1234yf feed as claimed in claim 1, further comprising the steps of:
a) passing the feed to a distillation column to separate top composition of ternary azeotrope composition “A” comprising R-1234yf, R-40 and R-134a;
b) optionally passing the ternary azeotrope composition “A” comprising R-1234yf, R-40 and R-134a through any one or more selected from an absorption tower, an adsorption tower and semipermeable membrane;
c) passing the composition obtained from step b) to another distillation column to separate top composition of binary azeotrope composition “B” comprising R-1234yf and R-134a and bottom composition comprising substantially pure R-1234yf.

### Claim 4 (depends on 2)

The A process for purification of R-1234yf feed as claimed in claim 2, further comprising the steps of:
a) passing the feed to a distillation column to separate top composition comprising R-22, OFCB, R-1234yf, R-40 and R-134a;
b) passing the top composition comprising R-22, OFCB, R-1234yf, R-40 and R-134a through any one of more selected from an absorption tower, adsorption tower and semipermeable membrane;
c) passing the composition obtained from step b) to another distillation column to separate top composition of binary azeotrope composition “B” comprising R-1234yf and R-134a and bottom composition comprising pure R-1234yf.

### Claim 5

A process for purification of R-1234yf feed comprising R-1234yf, R-40, R-134a, R-134, R-1225zc, and OFCB, said process comprising a step of separating a ternary azeotrope composition “C” comprising about 70 mole % to about 85 mole % of R-1234yf, about 5 mole % to about 15 mole % of R-134 and about 2 mole % to about 20 mole % of R-134a.

### Claim 6 (depends on 5)

A process for purification of R-1234yf feed as claimed in claim 5, further comprising a step of separating a binary azeotrope composition “D” comprising about 5 mole % to about 15 mole % of R-134 and about 85 mole % to about 95 mole % of 1234yf.

### Claim 7 (depends on 5)

The process for purification of R-1234yf feed as claimed in claim 5, further comprising the steps of:
a) passing the feed through any one or more selected from an absorption tower, adsorption tower and semipermeable membrane;
b) passing the composition obtained from step b) to another distillation column to separate top composition of ternary azeotrope composition “C” comprising R-1234yf, R-134, and R-134a and bottom composition comprising substantially pure R-1234yf;
c) recycling the top composition of ternary azeotrope.

### Claim 8

(canceled)

### Claim 9

(canceled)

### Claim 10 (depends on 3)

The process of claim 3, wherein the absorption tower contains chloroform or methanol.

### Claim 11 (depends on 3)

The process of claim 3, wherein the adsorption tower contains molecular sieves having mean pore diameter of the size ranging from 3 Å to 5 Å.

### Claim 12

(canceled)

### Claim 13 (depends on 3)

The process of claim 3, wherein semipermeable membrane includes polyethene or polypropylene.

### Claim 14

(canceled)

### Claim 15

(canceled)