PURPOSE: To provide the subject compound useful as a raw material of polyimides which is suitable for the production of protective films having various improved properties such as thermal stability and increased glass transition temp.
CONSTITUTION: The compound of formula I (A is direct bond, -CO-, -S-, -CF2-, etc.; R is a halogen, 1-6 C alkyl, OH, etc.), e.g. 2,2'-dichloro-4,4',5,5'- benzophenone-tetracarboxylic acid dianhydride, is obtained, for example, by allowing 4-chloro-o-xylene to react with oxalyl chloride in the presence of aluminum chloride, then oxidizing the compound thus obtained in the presence of nitric acid, and dehydrogenating the teracarboxylic acid intermediate thus obtained in an aromatic solvent at 180-290°C. The polyamide comprised of 50-100 mole % of the component of formula IV and 95-0 mole % of component of formula V is obtained by polycondensing the compound of formula I together with the compound of formula II [Z is a quadrivalent (substituted) aromatic group which is different from formula IV, wherein two carbony groups are bonded to o- and p-positions of the aromatic group in each case] with a diamine of formula H2N-X-NH2 (X is a divalent aromatic diamine) to be cyclized.
PASUKARU ARUFURETSUDO FUARUSHI