1,2-Benzenedicarboxylic acid, 4,4'-carbonylbis-, tetrapotassium salt 2479-49-4 3,3',4,4'-Benzophenonetetracarboxylic acid, tetrapotassium salt 56585-48-9 EINECS 260-270-2 Tetrapotassium 4,4'-carbonylbisphthalate