Patent ID: 7897823

Claim:
A process to produce an azeotrope composition comprising a hydrofluoroolefin containing 3 to 8 carbon atoms and hydrogen fluoride, said process comprising, dehydrofluorinating a hydrofluorocarbon containing at least one hydrogen and at least one fluorine on adjacent carbons, wherein said dehydrofluorinating is carried out in a reaction zone at a temperature from about 0° C. to about 1000° C., thereby forming a mixture comprising said hydrofluoroolefin, unreacted hydrofluorocarbon and hydrogen fluoride, wherein at least one of said hydrofluoroolefin and said hydrofluorocarbon are present in said product mixture as an azeotrope composition with hydrogen fluoride and are selected from the group consisting of CH3CF2CHF2 and CHF2CF=CH2; CF3CHFCH3 and CF3CH=CH2; CF3CH2CH2F and CF3CH=CH2; CHF2CH2CHF2 and CHF2CH=CHF; CF3CH2CF2CF3 and CF3CH=CFCF3; CF3CHFCHFCF3 and CF3CH=CFCF3; CH3CF2CF2CF3 and CH2=CFCF2CF3; CHF2CH2CF2CF3 and CHF2CH=CFCF3; CH3CF2CF2CHF2 and CH2=CFCF2CHF2; CHF2CH2CHFCF3 and CHF2CH=CHCF3; CHF2CHFCH2CF3 and CHF2CH=CHCF3; CF3CH2CHFCF2CF3 and CF3CH=CHCF2CF3; CF3CHFCH2CF2CF3 and CF3CH=CHCF2CF3; CF3CH2CHFCF2CF2CF3 and CF3CH=CHCF2CF2CF3; CF3CHFCH2CF2CF2CF3 and CF3CH=CHCF2CF2CF3; CH2FCHFCH2CF3 and CH2FCH=CHCF3; CH3CF(CF3)2 and CH2=C(CF3)2; (CF3)2CFCH2CF3 and (CF3)2C=CHCF3; CH3CH2CF2CF2CF2CF3 and CH3CH=CFCF2CF2CF3; C2F5CHFCH2CF2C2F5 and C2F5CH=CHCF2C2F5; C2F5CH2CHFCF2C2F5 and C2F5CH=CHCF2C2F5; CF3CHFCH2CF2CF2C2F5 and CFSCH=CHCF2CF2C2F5; and CF3CH2CHFCF2CF2C2F5 and CF3CH=CHCF2CF2C2F5, and distilling the mixture to produce a distillate composition comprising an azeotrope composition containing said hydrofluoroolefin and hydrogen fluoride and a column bottoms composition comprising said hydrofluorocarbon essentially free of hydrogen fluoride.