Study On Cu/SiO₂ Catalyst Of Dimethyl Oxalate Hydrogenation

Ethylene glycol is a chemical raw materials whick can be widely used in various industries. This paper was prepared by sol-gel Cu/SiO2 catalyst which is use for the hydrogenation of ethylene glycol dimethyl oxalate reaction, in order to enhance the catalytic performance Experiments from multiple angles with different methods investigated copper loading, experimental conditions, and the Ce、Zr additives influence on Cu/SiO2 catalyst. and a series of characterization was used for the catalyst, The results are as follows.(1) In the preparation of Cu/SiO2 catalyst,the conditions of the copper will have a relatively large impact on the activity of the catalyst. The results obtained that the copper loading of 20%, the conversion and selectivity of ethylene glycol dimethyl oxalate to the highest.(2) By soaking ammonia to change the properties of the catalyst, the hydrogenation activity of the catalyst were significantly different. The catalyst which is not by the affect of the ammonia,the conversion of dimethyl oxalate and ethylene glycol selectivity was only 89.9% and 79.6%. while the use of aqueous ammonia pH 11.5 soaking Cu/SiO2 catalyst, the catalytic performance has been significantly enhanced.(3) Changing the experimental conditions, we find that the catalyst at a reaction temperature 200℃, reaction pressure of 3MPa, hydroquinone ratio of 60 which could be the best performance. The conversion of dimethyl oxalate was 99.9%, the selectivity of ethylene glycol was 97.8%.(4) Considering the copper has a low melting point, and the copper is sensitive to the temperature. The catalyst at the high temperatures may become Sintering Quickly. In order to improve the anti-sintering performance of the catalyst, by doping with varying amounts of cerium nitrate, and find the effects of different methods of doping on its catalytic activity. By the conclusion of the experiments, the catalyst doped with 0.6% of the content of Ce can be the best anti-deactivation.(5) Copper in the hydrogenation process is easily changed from Cu2+ to Cu0, excessive the Cu0 may also reduce the activity of the catalyst, especially the selectivity of ethylene glycol. By doping different amounts of zirconium nitrate which was investigated for Cu SiO2 catalyst, in the doping amount of 0.4% of the Zr, The selectivity of dimethyl oxalate was 99.2%, and the selectivity of ethylene glycol was 93.9%.