Process for making 2,3,3,3-tetrafluoropropene and/or vinylidene fluoride

Patent metadata

Field	Value
Publication number	US-10071940-B2
Application number	US-201715709931-A
Country	US
Kind code	B2
Filing date	Sep 20, 2017
Priority date	Nov 12, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

Disclosed is a process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (HFO-1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane under conditions effective to produce a reaction product comprising HFO-1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2.

First claim

What is claimed is:

1. A process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (HFO-1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane to produce a reaction product comprising HFO-1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2;
wherein the pyrolysis is conducted at a temperature in the range of from about 750° C. to about 800° C. for a contact time of from about 2 seconds to about 25 seconds and at a pressure of about 1 atm.

2. The process of claim 1 , wherein the pyrolysis is conducted in a stainless steel tube reactor and wherein the reaction is quenched by cooling as said reaction product comes out of the reactor.

3. The process of claim 1 , wherein the pyrolysis provides a yield in the range of about 80% to about 90%.

4. The process of claim 1 , wherein the pyrolysis provides a conversion rate of about 70%.

5. The process of claim 1 , wherein the pyrolysis is conducted in a batch mode.

6. The process of claim 1 , wherein the pyrolysis is conducted in a continuous mode.

7. The process of claim 1 , further comprising the step of separating the mixture of the compounds 1234yf and vinylidene fluoride.

8. A process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (HFO-1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane to produce a reaction product comprising HFO-1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2;
wherein the pyrolysis is conducted at a temperature in the range of from about 750° C. to about 800° C. for a contact time of from about 2 seconds to about 25 seconds and at a pressure of about 1 atm; and
further comprising the step of forming the compound 1,1,2-trifluoro-2-trifluoromethyl-cyclobutane (TFMCB) by the thermal dimerization a mixture of hexafluoro-propene (HFP) and a stoichiometric excess of ethylene, in the presence of a polymerization or oligomerization inhibitor.

9. The process of claim 8 , wherein the HFP and ethylene were mixed in a reactor at a molar ratio of from 1:1 to 1:10.

10. The process of claim 8 , wherein the HFP and ethylene were mixed in a reactor at a molar ratio of from 1:1 to 1:6.

11. The process of claim 8 , wherein the inhibitor is present at from about 200 ppm to about 3% by weight.

12. The process of claim 8 , wherein the inhibitor is present at from about 500 ppm to 5000 ppm.

13. The process of claim 8 , wherein the inhibitor is selected from the group consisting of catechol and catechol derivatives, terpenes, quinones and combinations of two or more thereof.

14. The process of claim 8 wherein said inhibitor is selected from the group consisting of t-butyl catechol, limonene, pinene, 1,4-naphtho-quinone, 2,5-di-tert-butyl-hydroquinone, hydroquinone, hydroquinone monomethyl ether, mono-tert-butyl hydroquinone, para-benzoquinone, toluhydroquinone, trimethyl-hydroquinone and combinations of any two or more thereof.

15. The process of claim 8 , wherein the thermal dimerization is conducted at a temperature in the range of from about 250° C. to 450° C.

16. The process of claim 8 , wherein the thermal dimerization is conducted at a temperature in the range of from about 300° to 350° C.

17. The process of claim 14 , wherein the thermal dimerization is conducted for a reaction time in the range of from about one to five hours.

18. The process of claim 15 , wherein the thermal dimerization is conducted for a reaction time in the range of from about one to five hours.

19. The process of claim 8 , wherein any unreacted starting materials are recycled into a separate container.

20. The process of claim 8 , wherein the product TFMCB is decanted from the reactor at greater than 92% purity.

21. The process of claim 8 , wherein the product TFMCB is purified by distillation at greater than 99.8% purity.

Assignees

• Honeywell Int Inc

Inventors

• Banavali Rajiv
• Nair Haridasan K
• Zhai Yian

Classifications

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C07C17/361 Primary

  by reactions involving a decrease in the number of carbon atoms · CPC title

• C07C17/275 Primary

  of hydrocarbons and halogenated hydrocarbons · CPC title

• C09K2205/22

  All components of a mixture being fluoro compounds · CPC title

• C09K2205/122

  Halogenated hydrocarbons · CPC title