摘要 |
NEW MATERIAL:p-Terphenyl-3,4,3'',4''-tetracarboxylic acid expressed by formula I or dianhydride thereof expressed by formula II. USE:A raw material for excellent heat-resistant polyimide resins, curing agent, etc., for epoxy resins, phenolic resins, etc. PREPARATION:A 4-halogoeno-o-xylene is reacted with metallic Mg and converted into Grignard reagent expressed by formula III (X1 is Cl, Br or I) by a conventional method and a p-dihalogenobenzene expressed by formula IV (X2 is same as X1) is subjected to double cross coupling with the above- mentioned compound expressed by formula I in the presence of a nickel metal complex catalyst e.g. dichloro[1,2-bis(diphenylphosphino)ethane]nickel, etc., to afford a compound expressed by formula V, which is then oxidized with a permanganate, nitric acid or air in the liquid phase to provide the compound expressed by formula I. The resultant compound expressed by formula I is then cyclodehydrated while heating or with acetic anhydride or directly oxidized in the vapor phase to give the compound expressed by formula II.
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