process for the production of perfluoropolyoxyalkylene with ocf2h, ocf2cf2h or ocf (cf3) h groups

摘要

A process for preparing perfluoropolyoxyalkylenes having -OCF2H, -OCF2CF2H and -OCF(CF3)H end groups and a number average molecular weight from 120 to 3,000, by decarboxylation of the corresponding perfluoropolyoxyalkylenes having -OCF2COOH, -OCF2CF2COOH, -OCF(CF3)COOH end groups, in the presence of catalytic amounts of salts formed by perfluoropolyoxyalkylenes having end groups selected from -OCF2COOZ, -OCF2CF2COOZ and -OCF(CF3)COOZ, wherein Z is a monovalent cation of the group Ia or Ib or Z is -NR4+ wherein R is hydrogen or a C1-C4 alkyl, using ratios between Z and the -COOH equivalents of the perfluoropolyoxyalkylenes to be decarboxylated from 0.01 to 0.08, at a temperature between 120 DEG C and 180 DEG C, in the presence of water, at pH 5 and at a pressure comprised between 2 and 80 atmospheres.