Study On Catalysts And Reaction Paths For Hydrogenation Of Dimethyl Oxalate

Nowadays,problems of environment and energy have become more and more urgent for the society.How to conduct high efficient and clean utilization of coal resource is the problem needed to be solved.Ethanol is widely used in chemical industry as well as clean fuel.Hydrogenation of dimethyl oxalate?DMO?to produce ethanol is a promising and competitive route.This dissertation focuses on the development of two-step synthesis route.Through the analysis to the product of DMO hydrogenation,it indicates that the reaction rate of ethylene glycol hydrogenation is much slower than DMO hydrogenation.Base on this conclusion,the article proposes a new two-step approach of ethanol production: after completely conversion of ethylene glycol at 473 K,products will be transferred into the container of the second stage,and continue reacting into ethanol at 553 K.Compared to the traditional method,the new method inhibits side reactions,improving selective of target product.Basic sites are discovered as the efficient factor related to characters of catalysts,so decreasing the number of basic sites can inhibit side reactions.In this article,aluminum was introduced in the production of Cu/SiO₂ catalyst to change the acid and basic properties on the surface.Through the activity evaluation,catalyst with modified surface properties decreased the products of Guerbet?C3-C4 alcohol?.In addition,the modified catalyst was applied in the two-step reactions,leading to a much better ethanol selectivity.In another hand,as a light hydrogenated product,methyl glycolate is also an important raw chemical material.Through the investigation on nickel-based catalysts,the comparative selectivity of methyl glycolate was achieved because of the strong adsorption ability of DMO,which made desorption of DMO quite difficult.Doping Cu and increasing reduction level were applied to improve DMO conversion.However,the selectivity of ethylene glycol increased with Cu modified catalysts.Alternatively,when the reduction level of nickel-based catalysts was improved,a higher conversion of DMO was obtained with a higher selectivity of methyl glycolate.