Azeotrope-like composition of 2-chloro-3,3,3-trifluoropropene (HCFC-1233xf) and hydrogen fluoride (HF)
View Patent ↗Provided are azeotropic and azeotrope-like compositions of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and hydrogen fluoride (HF). Such azeotropic and azeotrope-like compositions are useful as intermediates in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf).
1. A method of forming an azeotropic or azeotrope-like composition which comprises forming a blend consisting essentially of from about 79.3 mole percent to about 85.3 mole percent hydrogen fluoride and from about 14.7 mole percent to about 20.7 mole percent 2-chloro-3,3,3-trifluoropropene to thereby form an azeotropic or azeotrope-like composition having a boiling point of from about 0° C. to about 61° C. at a pressure of from about 15 psia to about 107 psia.
2. The method of claim 1 wherein the composition consists of hydrogen fluoride and 2-chloro-3,3,3-trifluoropropene.
3. The method of claim 1 wherein the hydrogen fluoride in present in an amount of from about 82.5±1.2 mole percent.
4. The method of claim 1 further comprising the step of separating 2-chloro-3,3,3-trifluoropropene from an azeotropic or azeotrope-like composition of 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride using pressure swing distillation.
5. The method of claim 1 further comprising the step of feeding the azeotropic or azeotrope-like composition of 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride to a fluorination reactor as a source of hydrogen fluoride.
6. A method for removing 2-chloro-3,3,3-trifluoropropene from a mixture containing 2-chloro-3,3,3-trifluoropropene and at least one impurity, which comprises adding hydrogen fluoride to the mixture in an amount sufficient to form an azeotropic or azeotrope-like composition comprising from about 79.3 mole percent to about 85.3 mole percent hydrogen fluoride and from about 14.7 mole percent to about 20.7 mole percent 2-chloro-3,3,3-trifluoropropene, and thereafter separating the azeotropic composition from the impurity.
7. The method of claim 6 wherein the impurity does not form an azeotropic mixture with 2-chloro-3,3,3-trifluoropropene, hydrogen fluoride or a mixture of 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride.
8. The method of claim 6 wherein the impurity does form an azeotropic mixture with 2-chloro-3,3,3-trifluoropropene, hydrogen fluoride or a mixture of 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride.
9. The process of claim 6 wherein the impurity comprises a halocarbon.
10. The method of claim 6 wherein the impurity is miscible with 2-chloro-3,3,3-trifluoropropene.
11. The method of claim 6 wherein the impurity comprises one more of 1,1,1,2,3-pentachloropropane; 1,1,2,3-tetrachloropropene; 2,3,3,3-tetrafluoropropene; 2,3-dichloro-3,3-difluoropropene; 1,1,1,2,2-pentafluoropropane and 1,2-dichloro-3,3,3-trifluoropropene.
12. The method of claim 6 wherein the separating is conducted by distillation.
13. The method of claim 6 wherein the azeotropic composition consists essentially of about 82.5±1.2 mole percent hydrogen fluoride and about 17.5±1.2 mole percent 2-chloro-3,3,3-trifluoropropene.