Study On The Preparation Of Methyl Glycolate In One Step

The preparation of methyl glycolate from ethylene glycol and methanol by one-step oxidative esterification was studied in this paper. Series of catalysts camparing experiments were carried out, which showed that Au/Al2O3 supported catalyst possessed good activity for the oxidative esterification. Based on the researches, the optimum reaction conditions for synthesis of methyl glycolate were determined.At first, the P-Mo-V heteropoly acids with Keggin structure were prepared and used for ethylene glycol oxidative esterification as a catalyst. Reaction results showed that these P-Mo-V heteropoly acid catalysts exhibited no activity. Then, Au/Al2O3 catalysts were prepared by deposition-precipitation method. The influences of Al2O3 grain size, quantity of Au loading and catalyst calcination temperature on the reaction conversion and selectivity were examined. The Au/Al2O3 catalyst prepared with large pore size support, Au weight loading between 0.5% and 1.0% and calcined under 300℃for 2h, showed favorable performance.The effects of reaction temperature, reaction pressure, oxygen concentration and raw material ratio were investigated. Both of the conversion of ethylene glycol and selectivity of methyl glycolate could reach up to 80% under the optimum conditions as follow:temperature at 120℃, pressure of 0.45 MPa (O2:N2=1:1～1:2) and the molar ratio of ethylene glycol to methanol equal to 1:10.