Study On Catalysts Of Hydrogenation Of Dymethyl Oxalate To Ethylene Glycol

Nowadays, the C1 chemistry based on coal and natural gas has risen to a new level. Many new important chemicals can be synthesized by using the syn-gas （CO+H2） as raw materials . Development of the process producing ethylene glycol （EG） from the syn-gas, in order to substitute the conventional route from petroleum, is of great significance. Two steps are included in this process routes: the coupling of CO with nitrite esters to obtain oxalates and the hydrogenation of oxalates to EG. The catalyst of the hydrogenation is a difficulty. Cu/SiO₂ catalysts were prepared via a homogeneous deposition–precipitation method using urea as precipitator. The activities of the catalysts were test using a fixed-bed micro reactor. The preparation conditions, operation conditions of the hydrogenation and the effect of the promoters were studied.The preparation conditions such as the initial copper concentrations, urea concentrations and copper loadings have a great influence to the structures and activities of the catalysts. The results indicated that the conditions of copper ion concentration 0.3mol·L-1, urea concentration 0.6 molï¹'L-1 and less than 30% copper loading gave the best catalyst. The catalysts preparation process was then scaled up to be carried out in a 5 liter reactor at the optimal conditions and the catalyst was tested in different operation conditions. Temperature was the factor which affects the reaction mostly. It should not be higher than 448K in order to get a good selectivity of EG. It is concluded that the aggregation of copper grain and absorption of organic molecular were the major transformation of the catalysts during the reaction.The promoters of Zr and Mn did affect the catalysts’performances. The promoter Zr can improve the thermol stability of the catalysts and Mn can restrain the activity of Cu/SiO₂ catalyst to help reduce the side-reaction.