Preparation of 1,1,1,3,3-pentafluoropropane

• US 5,895,825 A
• Filed: 12/01/1997
• Issued: 04/20/1999
• Est. Priority Date: 12/01/1997
• Status: Expired due to Term

• Current Assignee: Arkema Incorporated (Arkema)
• Original Assignee: Elf Atochem North America, Inc. (Totalenergies Se)
• Inventors: Chen, Bin, Bolmer, Michael S., Elsheikh, Maher Y.
• Primary Examiner(s): SIEGEL, ALAN M
• Application Number:
  US08/980,747
• Time in Patent Office: 505 Days
• Field of Search: 570/169, 570/167, 570/164
• US Class Current: 570/167
• CPC Class Codes: C07C 17/087 to unsaturated halogenated hydrocarbons
• CPC Class Codes: C07C 17/206 the other compound being HX
• CPC Class Codes: C07C 17/38 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 17/383 by distillation
• CPC Class Codes: C07C 19/08 containing fluorine
• CPC Class Codes: C07C 21/18 containing fluorine

Abstract

A process for the preparation of 245fa is provided, wherein 1233zd is first fluorinated to 1234ze, followed by fluorination of 1234ze to 245fa. 245fa is a known foam blowing agent and refrigerant.

Claims

1. A process for preparing 1,1,1,3,3-pentafluoropropane which comprises (a) contacting 1,1,1 -trifluoro-3-chloro-2-propene with hydrogen fluoride in a first reaction zone under conditions sufficient to produce a reaction mixture containing 1,1,1,3-tetrafluoro-2-propene;

and (b) seperating the 1,1,1,3-tetrafluoro-2-propene from said reaction mixture and contacting it with hydrogen fluoride in a second reaction zone under conditions sufficient to produce 1,1,1,3,3-pentafluoropropane.

2. A process as in claim 1 wherein the molar ratio of hydrogen fluoride to 1,1,1,3-tetrafluoro-2-propene in step (b) is at most about 3 to 1.

3. A process for preparing 1,1,1,3,3-pentafluoropropane which comprises (a) contacting 1,1, 1-trifluoro-3-chloro-2-propene with hydrogen fluoride in a first reaction zone under conditions sufficient to produce a reaction mixture containing 1,1,1,3-tetrafluoro-2-propene, 1,1,1,3,3-pentafluoropropane, and hydrogen chloride, together with unreacted 1,1,1-trifluoro-3-chloro-2-propene and hydrogen fluoride;

and (b) separating the 1,1,1,3-tetrafluoro-2-propene from said reaction mixture and contacting it with hydrogen fluoride in a second reaction zone under conditions sufficient to produce 1,1,1,3,3-pentafluoropropane.

4. A process as in claim 3 wherein the 1,1,1,3,3 -pentafluoropropane, 1,1,1-trifluoro-3-chloro-2-propene and hydrogen fluoride are separated from the reaction mixture in step (a) and recycled to the first reaction zone.

5. A process as in claim 3 wherein the reaction mixture from step (a) is subjected to a first distillation to separate the reaction mixture into a first stream containing the 1,1,1,3,3-pentafluoropropane, 1,1,1-trifluoro-3-chloro-2-propene and hydrogen fluoride and a second stream containing the 1,1,1,3-tetrafluoro-2-propene and hydrogen chloride, the hydrogen chloride in the second stream then being separated from the 1234ze via absorption or a second distillation.