Catalytic liquid phase fluorination of C 2 chloroalkanes and C 2 chloro alkenes with SbCl 5-HF

Abstract

The catalytic liquid phase fluorination of C 2 chloroalkanes and C 2 chloroalkenes to produce hydrogenochlorofluorocarbons is carried out with SbCl 5 and HF at 60–70 °C and 1 MPa. The catalytic species is prepared by reacting SbCl 5 and HF (xs) at 60 °C, for 3 hr. The excess of HF is vented; the chlorocompound is added to the reactor, followed by addition of HF. The following results are obtained: CH 3CCl 2F (73%) and CH 3CClF 2 (27%) are obtained from CH 3CCl 3 with a reaction rate equal to 1.45×10 −2 mole h −1 g −1 (SbCl 5). CCl 2HCCl 2F (82%) and CHCl 2CF 2Cl (18%) are obtained from CCl 2CCl2 with a reaction rate of 4.52×10 −3 mole h −1 g −1 (SbCl 5). The fluorination of CH 3CCl 3 is accompanied by a dehydrochlorination which gives CHCCl 2. This chloroolefin oligomerizes to give partially dehydrochlorinated by-products with general formula CH 3−(CClCH) x−CCl 3 (linear or branched). The compounds x=2 and x=4 could be isolated and hydrolysed with 6N H 2SO 4 to give 6-methyl-4-chloropyrone, 3,5-dichlorophenol and 2-methyl-5,7-dichlorochromone. Minor amounts of partially fluorinated oligomers are also formed. We thank the Atochem Company for financial support.