ETHER-LINKED ARYL TETRACARBOXYLIC DIANHYDRIDES

摘要

1503968 Tetracarboxylic dianhydrides NATIONAL AERONAUTICS & SPACE ADMINISTRATION 11 July 1975 [16 July 1974] 29193/75 Heading C2C Novel tetracarboxylic dianhydrides of general formula wherein Rf is a perfluoroalkylene group -(CF 2 ) n - or a perfluoroalkylene ether group -(CF 2 ) m -O-(CF 2 ) m - in which n=2-10 and m=1-10, are prepared by reacting 3,4-bis-(trifluoromethyl) phenol and a perfluoroalkanedioyl halide where X is F, Cl or Br, in a molar ratio of at least 2 : 1 to produce the corresponding 3,4-bis- (trifluoromethyl) phenol perfluoroalkane dioate, fluorinating the latter to the corresponding 3,31,4,41 - tetrakis - (trifluoromethyl) - α,# - diphenoxy polyfluoroalkane, hydrolysing the latter to the corresponding 3,31,4,41-tetracarboxylic acid-α, #-diphenoxy polyfluoroalkane and dehydrating the acid to give the dianhydride. Preferably n is 4-6. In the examples 1,5-diphenoxydecafluoropentane - 31,311,41,411 - tetracarboxylic acid dianhydride is prepared. 3,4-Bis-(trifluoromethyl) phenol (I) is obtained by diazotization of 3,4-bis-(trifluoromethyl) aniline. 3,4 - Bis - (trifluoromethyl) phenyl hexafluoroglutarate (II) is prepared from the phenol (I) above and perfluoroglutaryl chloride. 31,311,41,411 - Tetrakis - (trifluoromethyl) - 1,5- diphenoxydecafluoropentane (III) is obtained by treating the compound (II) above with HF/SF 4 . 1,5 - Diphenoxydecafluoropentane - 31,311,41,411- tetracarboxylic acid is produced by the acid hydrolysis of the compound (III) above.