Hydrogen-free halomethanes prodn - from fluorine-contg hydrogen-free methanes by a friedel-crafts reaction

摘要

Process for prepg. hydrogen-free halogen methanes from fluorine-contg. H-free halogen methanes of different constitution in the presence of Friedel-Craft catalysts. F-contg. H-free halogen methanes (A) e.g. CFCl3, CFBr3, CF2Br2 are reacted with e.g. CCl4, CBr4, CCl3Br, CCl2Br2 (B) in the presence of pref. AlCl3.AlBr3 or mixtures thereof in a mol. ratio A:B of 4-1:1 at -10 to +150 degrees pref. 20-80 degrees C. Thus from CF2Br2 and CCl4 is obtd. a mxiture of CF2Cl2, CF3Br, CF2ClBr and CF2Br2 which may be separated by fractionation. The products are propellents, fire extinguishers and artificial foam producers.