2, 3, 3apos; , 4apos; preparation method of-diphenyl ether tetracarboxylic dianhydride

The invention discloses a preparation method of 2, 3, 3 ', 4'-diphenyl ether tetracarboxylic dianhydride, which comprises the following steps: carrying out amidation reaction on 3-chlorophthalic anhydride and aniline to obtain a first intermediate, carrying out condensation reaction on the first intermediate and 3, 4-dimethylphenol to obtain a second intermediate, and simultaneously oxidizing and hydrolyzing the second intermediate by using nitric acid under the conditions of high temperature and high pressure to obtain 2, 3, 3 ', 4'-diphenyl ether tetracarboxylic dianhydride; and 2, 3, 3 ', 4'-diphenyl ether tetracarboxylic acid is subjected to dehydration to form anhydride, such that 2, 3, 3 ', 4'-diphenyl ether tetracarboxylic acid dianhydride is obtained. According to the method disclosed by the invention, aniline and 3-chlorophthalic anhydride are subjected to amidation reaction to obtain a second intermediate containing phenyl, and the second intermediate can be oxidized and hydrolyzed by nitric acid at