Process for the manufacture of halocarbons and selected compounds and azeotropes with HF
View Patent ↗A liquid phase process is disclosed for producing halogenated alkane adducts of the formula CAR 1 R 2 CBR 3 R 4 (where A, B, R 1 , R 2 , R 3 , and R 4 are as defined in the specification) which involves contacting a corresponding halogenated alkane, AB, with a corresponding olefin, CR 1 R 2 ═CR 3 R 4 in a dinitrile or cyclic carbonate ester solvent which divides the reaction mixture into two liquid phases and in the presence of a catalyst system containing (i) at least one catalyst selected from monovalent and divalent copper; and optionally (ii) a promoter selected from aromatic or aliphatic heterocyclic compounds which contain at least one carbon-nitrogen double bond in the heterocyclic ring. When hydrochlorofluorocarbons are formed, the chlorine content may be reduced by reacting the hydrochlorofluorocarbons with HF. New compounds disclosed include CF 3 CF 2 CCl 2 CH 2 CCl 3 , CF 3 CCl 2 CH 2 CH 2 Cl and CF 3 CCl 2 CH 2 CHClF. These compounds are useful as intermediates for producing hydrofluorocarbons. Azeotropes of CClF 2 CH 2 CF 3 with HF and azeotropes of CF 3 CH 2 CHF 2 with HF are also disclosed; as are process for producing such azeotropes. A process for purification of certain hydrofluorocarbons and/or chloro-precursors thereof from mixtures of such compounds with HF is also disclosed.
1. A process for producing CF 3 CH 2 CHF 2 , comprising:
fluorinating CCl 3 CH 2 CHCl 2 with HF to produce a fluorination product comprising CF 3 CH 2 CHF 2 and HF;
obtaining an azeotropic mixture of CF 3 CH 2 CHF 2 with HF from the fluorination product; and
purifying CF 3 CH 2 CHF 2 from said mixture.
2. The process of claim 1 wherein the azeotropic mixture comprises (a) from about 44 to 84 mole percent HF and (b) from about 56 to 16 mole percent CF 3 CH 2 CHF 2 , and exhibits a relative volatility of about 1 at a pressure within the range of 5.5 kPa to 3850 kPa when the temperature is adjusted within the range of −50° C. to 130° C.
3. The process of claim 2 wherein the azeotropic mixture is distilled in a high pressure distillation column to yield an azeotropic distillate of HF and CF 3 CH 2 CHF 2 and a bottoms containing HF; and wherein the azeotropic distillate is further distilled in a low pressure distillation column to yield another azeotropic distillate of HF and CF 3 CH 2 CHF 2 and a bottoms of essentially pure CF 3 CH 2 CHF 2 .
4. The process of claim 2 wherein the azeotropic mixture is distilled in a low pressure distillation column to yield an azeotropic distillate of HF and CF 3 CH 2 CHF 2 and a bottoms containing essentially pure CF 3 CH 2 CHF 2 ; and wherein the azeotropic distillate is further distilled in a high pressure distillation column to yield another azeotropic distillate of HF and CF 3 CH 2 CHF 2 and a bottoms containing HF.
5. The process of claim 2 wherein the CCl 3 CH 2 CHCl 2 is produced by reacting CCl 4 with CH 2 ═CHCl.
6. The process of claim 5 wherein the CCl 4 is reacted with the CH 2 ═CHCl in a dinitrile or cyclic carbonate ester solvent which divides the reaction mixture into two liquid phases, and in the presence of a catalyst system containing (i) at least one catalyst selected from the group consisting of monovalent and divalent copper and (ii) a promoter selected from aromatic and aliphatic heterocyclic compounds which contain at least one carbon-nitrogen double bond in the heterocyclic ring.