Patent ID: 8008523
Filing Date: 2011-08-30
Classification: C08G

Abstract:
1. A process for preparing monocarboxylic perfluoropolyethers of formula: wherein: X=H, a linear or branched, when possible, alkyl radical R with a number of carbon atoms between 1 and 10, or a C Y=F, CF t is an integer from 1 to 3, t=1 when Y=CF A is a linear or branched, when possible, C z is an integer 0 or 1; R having molecular weight or number average molecular weight in the range 180-8,000; comprising the following steps: a) one or more distillations of perfluoropolyethers of formula: b) partial fluorination of the fraction obtained in a) until obtaining a content of neutral end groups from 40% to 60% molar with respect to the total of the end groups; c) esterification c1) and/or hydrolysis c2) as follows: c1) esterification of the mixture obtained in b) with an alcohol of formula R—OH wherein R is as above, in stoichiometric amount with the functional acylfluoride end groups of the mixture obtained in b) and distillation of the formed HF; c2) hydrolysis of the mixture obtained in b) with water used in stoichiometric ratio with the functional acylfluoride end groups of the mixture obtained in b), by distilling the formed HF; d) distillation of the product obtained in c1) or in c2) by operating at temperatures from +20° C. to +300° C. and under a pressure between 10