Synthesis Of Dicarboxylic Esters From Cleavage Of Cyclic Ethers By Carboxylic Anhydrides

A series of Al-Mg composite oxide catalysts were designed and studied for catalysizing one step alkoxylation (ethoxylation or propoxylation) of linear/cyclic carboxylic acid anhydride. The optimum catalysts for ethoxylation of acetic anhydride and propoxylation of acetic anhydride were screened out respectively. The reaction between succinic anhydride with ethylene oxide as well as propylene oxide were investigated.A technique was described about producing ethylene glycol dicarboxylic acetate (EGDBA) by inserting ethylene oxide (EO) into the carboxylic anhydrides(linear) directly with catalyst RAs. The products were characterized by FTIR, ESI-MS, 1H-NMR and GC-MS. It was found that the catalyst, RA-4, has the highest production selectivity for ethylene glycol diacetate (EGDA). The optimum selectivity of EGDA was 97.8% ( w/w) under the following optimized reaction conditions: amount of Al-Mg composite is 1.6 g/100 g acetic anhydride, the initial pressure 0, n(PO) : n(AA)=1:1 and dropping EO while maintaing the pressure of the system of 0.35 MPa, at the temperature of 130～135℃. The production selectivity of EGDA was not decreased if the recycled catalyst had been reactivated.The product of propylene oxide (PO) reacted with carboxylic acid anhydride(linear) catalyzed by FXs was identified by FTIR, ESI-MS and 1H-NMR analysis. The catalyst FX-4 has the highest production selectivity of propylene glycol diacetate (PGDA). The optimum selectivity of PGDA (98.2%, w/w) was obtained under following suitable conditions: amount of Al-Mg composite is 1.6 g/100 g acetic anhydride, n(PO) : n(AA)=1:1 and dropping PO while maintaing the pressure of the system of 0.4 MPa under the temperature of 130～135℃.The reaction of succinic anhydride with EO/PO using Al-Mg composite oxide as catalyst were explored, The product was analyzed by FTIR and ESI-MS, The product of EO and SA is linear polymer. It was assumed that propylene oxide was inserted into the anhydride and formed a compound with cyclic structure. The initial compound then furtherly react with themselves as well as PO to form larger cyclic compounds.