Process for making 2,3,3,3-tetrafluoropropene and/or vinylidine fluoride
View Patent ↗Disclosed is a process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane under conditions effective to produce a reaction product comprising 1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2.
1. A process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane (TFMCB), wherein the TFMCB has a purity greater than 92%, under conditions effective to produce a reaction product comprising 1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2.
2. The process of claim 1 , wherein the pyrolysis is conducted at a temperature in the range of from about 750° C. to about 800° C. and for a contact time of from about 2 seconds to about 25 seconds and at a pressure of about 1 atm.
3. 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 the products come out of the reactor.
4. A process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane under conditions effective to produce a reaction product comprising 1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2;
wherein the pyrolysis provides a yield in the range of about 80% to about 90%.
5. The process of claim 1 , wherein the pyrolysis provides a conversion rate of about 70%.
6. The process of claim 1 , wherein the pyrolysis is conducted in a batch mode.
7. The process of claim 1 , wherein the pyrolysis is conducted in a continuous mode.
8. The process of claim 1 , further comprising the step of separating the mixture of the compounds 1234yf and vinylidene fluoride.
9. A process for the formation of a mixture of the compounds 2,3,3,3-tetrafluoropropene (1234yf) and vinylidene fluoride, comprising pyrolyzing 1,1,2-trifluoro-2-trifluoro-methyl-cyclobutane under conditions effective to produce a reaction product comprising 1234yf and vinylidene fluoride in a 1234yf:vinylidene fluoride molar ratio of from about 0.5 to about 1.2;
the process 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; and
wherein the TFMCB has a purity greater than 92%.
10. The process of claim 9 , wherein the HFP and ethylene were mixed in a reactor at a molar ratio of from 1:1 to 1:10.
11. The process of claim 9 , wherein the HFP and ethylene were mixed in a reactor at a molar ratio of from 1:1 to 1:6.
12. The process of claim 9 , wherein the inhibitor is present at from about 200 ppm to about 3% by weight.
13. The process of claim 9 , wherein the inhibitor is present at from about 500 ppm to 5000 ppm.
14. The process of claim 9 , wherein the inhibitor is selected from the group consisting of catechol and its derivatives, terpenes, quinones and combinations of two or more thereof.
15. The process of claim 9 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.
16. The process of claim 9 , wherein the thermal dimerization is conducted at a temperature in the range of from about 250° C. to 450° C.
17. The process of claim 9 , wherein the thermal dimerization is conducted at a temperature in the range of from about 300° to 350° C.
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 16 , wherein the thermal dimerization is conducted for a reaction time in the range of from about one to five hours.
20. The process of claim 9 , wherein any unreacted starting materials are recycled into a separate container.
21. The process of claim 9 , wherein the product TFMCB is purified by distillation at greater than 99.8% purity.