Pharmaceutical IntermediateChina Pyromellitic Dianhydride/Pmda/ Benzene-1, 2, 4, 5-Tetracarboxylic Dianhydrid 89-32-7, Find details about China CAS No. 89-32-7, Pyromellitic Dianhydride from Pyromellitic Dianhydride/Pmda/ Benzene-1, 2, 4, 5-Tetracarboxylic Dianhydrid 89-32-7