THE PURIFICATION OF PERFLUORINATED COMPOUNDS FOR COMMERCIAL USE

Two procedures for the purification of perfluorinated compounds have b een studied: the decomposition of impurities using concentrated alkali , and additional fluorination of products with elementary fluorine cat alysed by fluorides of transition metals. Characteristics of purified products of several classes (perfluorinated alkanes, ethers and trialk ylamines) have been presented. The problems of systematization of some classes of perfluoroorganic compounds-alkanes, ethers, tertiary amine s, cyclic analogues based on their physicochemical properties have bee n discussed. The connection between the change of boiling points of pe rfluorinated compounds and the number of carbon atoms has been establi shed and the corresponding empirical equation has been proposed. Quest ions of interchangeability of perfluorinated organic compounds of seve ral classes, for use as dielectrics, have been discussed. The influenc e of admixtures of by-products on the dielectric properties of perfluo rinated compounds has been considered. (C) 1998 Elsevier Science S.A.