for the following products
1,2,4-Benzenetricarboxylic acid 1,2-anhydride ethylene ester | Ethane-1,2-diyl bis(1,3-dioxo-1,3-dihydroisobenzo-furan-5-carboxylate) | Ethylene glycol bis(4-trimellitate anhydride) and Ethylene bis[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate]
