4,5-Dichlorophthalic anhydride942-06-331 % similar 2-Methyl-6-nitrobenzoic anhydride434935-69-031 % similar Perylenetetracarboxylic dianhydride128-69-830 % similar 5,5'-Bi-2-benzofuran-1,1',3,3'-tetrone2420-87-330 % similar 2,3-Naphthalenedicarboxylic anhydride716-39-230 % similar