Synonyms: Phthalicanhydride, 4,4'-sulfonyldi- (7CI,8CI); 3,3',4,4'-Diphenyl sulfonetetracarboxylic anhydride; 3,3',4,4'-Diphenyl sulfone tetracarboxylicdianhydride; 3,3',4,4'-Diphenylsulfoxide tetracarboxylic acid;3,3',4,4'-Tetracarboxydiphenyl sulfone dianhydride; 3,4,3',4'-Diphenylsulfonete tracarboxylic acid dianhydride; 4,4'-Diphthalic anhydride sulfone;4,4'-Sulfonylbis(phthalic anhydride); 4,4'-Sulfonyldiphthalic acid dianhydride;4,4'-Sulfonyldiphthalic anhydride; Bis(3,4-dicarboxyphenyl)sulfone dianhydride;NSC 689416; Rikacid DSDA