Dehydrohalogenation of hydrochlorofluorocarbons
A dehydrohalogenation product includes a hydrochlorofluorocarbon mixture of a fluoroolefin of formula RCX=CZQ and a halofluoroalkane of formula RCXYCZQT. R is a perfluorinated alkyl group and X, Z, and Q are independently H or halogen. One of Y and T is H and the other is Cl, Br, or I. About 80% or greater of the hydrochlorofluorocarbon mixture is the fluoroolefin. The dehydrohalogenation product also includes a caustic agent and a solvent. In some embodiments, the dehydrohalogenation product is free of any catalyst, including any phase transfer catalyst.
1. A dehydrochlorination process comprising vigorously contacting a chlorofluoroalkane of formula RCXYCZQT in an aqueous solvent comprising NaOH in a molar ratio of about 0.5 to about 2.0 of NaOH:chlorofluoroalkane, in the absence of any additional phase transfer catalyst, at a temperature in the range of about 30° C. to about 80° C. to produce a product comprising a fluoroolefin of formula RCX=CZQ, wherein R is a perfluorinated alkyl group and X, Z, and Q are independently H or fluorine, and one of Y and T is H and the other is Cl, wherein the conversion by the dehydrochlorination process is at least 95% of the maximum based on a starting ratio of NaOH and chlorofluoroalkane.
2. The dehydrochlorination process of claim 1 , wherein the conversion by the dehydrochlorination process is at least 98% of the maximum based on the starting ratio of NaOH and chlorofluoroalkane.
3. The dehydrochlorination process of claim 1 , wherein RCX=CZQ comprises one of CF 3 CF═CH 2 , CF 3 CH═CHF, and CF 3 CCl═CH 2 .
4. The dehydrochlorination process of claim 3 , wherein RCX=CZQ comprises CF 3 CF═CH 2 .
5. The dehydrochlorination process of claim 1 , wherein the aqueous solvent further comprises a co-solvent.
6. The dehydrochlorination process of claim 1 , wherein the dehydrohalogenation is conducted for about 1 to 120 minutes.
7. The dehydrochlorination process of claim 6 , wherein the dehydrohalogenation is conducted for about 10 to about 45 minutes.
8. The dehydrochlorination process of claim 1 , wherein the fluoroolefin is a chlorofluoroolefin.
9. The process of claim 1 , wherein the vigorous contacting involves agitation.
10. The process of claim 1 , wherein the vigorous contacting involves a mixing power at a horsepower in the range of 0.5 to 40 per 1000 gallons.
11. The process of claim 10 , wherein the mixing power is at a horsepower in the range of 1.2 to 40 per 1000 gallons.
12. The process of claim 1 , wherein the temperature is in the range of about 50 to about 80° C.
13. The process of claim 1 , wherein the aqueous solvent is about 12 wt % NaOH.
14. The process of claim 1 , wherein the molar ratio of NaOH:chlorofluoroalkane is sufficient to convert at least 99% of the chlorofluoroalkane.
15. A composition comprising:
a hydrochlorofluorocarbon mixture comprising:
a fluoroolefin of formula RCX=CZQ, wherein R is a perfluorinated alkyl group and X, Z, and Q are independently H or fluorine; and
a chlorofluoroalkane of formula RCXYCZQT, wherein one of Y and T is H and the other is Cl; and
an aqueous solvent comprising NaOH in a molar ratio of 0.5 to 2.0 of NaOH:hydrochlorofluorocarbon mixture.
16. The composition of claim 15 , wherein RCX=CZQ comprises one of CF 3 CF═CH 2 , CF 3 CH═CHF, and CF 3 CCl═CH 2 .
17. The composition of claim 16 , wherein RCX=CZQ comprises CF 3 CF═CH 2 .
18. The composition of claim 15 , the aqueous solvent further comprising a co-solvent.
19. The composition of claim 15 , wherein the NaOH is about 12 wt % in aqueous solvent.
20. The composition of claim 15 , wherein the composition is free of any additional phase transfer catalyst and wherein the molar ratio of NaOH:chlorofluoroalkane is sufficient to convert at least 95% of the chlorofluoroalkane based on a starting ratio of NaOH and chlorofluoroalkane.