Application Of Modified Copper Based Catalyst In The Hydrogenation Of Dimethyl Oxalate

Methyl glycolate?MG?,as an important chemical intermediate,has been widely used in the fields of medicine,chemical industry and agriculture.The present study catalyst for the synthesis of MG in hydrogenation of dimethyl oxalate?DMO?mainly concentrated in the Cu-noble metal alloy catalyst and Ag catalyst,while the MG high yield of these two kinds of catalysts,but the overall cost of the catalyst preparation.In the study of the catalyst support,the main supporter research is the SiO₂,and the research on the complex supporter catalyst is rarely reported.Based on this,Cu-Ni/SiO₂,Cu/ZrO₂-SiO₂ and Cu/CS-SiO₂ catalysts were prepared by adding Ni promoter,ZrO₂ and carbon microspheres?CS?.The catalyst can be used to synthesize MG under mild conditions,and the effects of modified copper based catalysts on catalytic activity are discussed.The main contents and conclusions of this paper are as follows: 1.Preparation of Cu-Ni/SiO₂ catalysts and application in DMO hydrogenation to MGCu-Ni/SiO₂ series catalysts were prepared by hydrothermal method.Under the same reaction conditions,by force of contrast the total metal loading,different Cu/Ni molar ratio,the 20%Cu1Ni1/SiO₂ catalyst in the reaction yield of MG was the highest,reached 70% and the stable operation of more than 100 hours.The characterization of the catalyst was carried out.The results showed that the molar ratio of Cu/Ni had a certain influence on the specific surface area,dispersion and the proportion of Cu+ to the catalyst.2.Preparation of Cu/ZrO₂-SiO₂ catalyst and application in DMO hydrogenation to MGCu/ZrO₂-SiO₂ series catalyst is prepared by the classic ammonia evaporation method,through the Cu load,different ZrO₂/SiO₂ mass ratio and other conditions.Under the same reaction conditions,the activity of the catalyst was determined,and the yield of 20%Cu/1ZrO₂-1SiO₂ catalyst in the reaction of MG was the highest,which could reach 81% of the yield and could run stably for more than 100 hours.Compared with the single carrier ZrO₂ and SiO₂ catalyst,the catalyst of the composite carrier ZrO₂-SiO₂ showed better catalytic activity.Through the characterization of the catalyst,it was found that the addition of ZrO₂ could improve the dispersion of Cu on the carrier,and the content of Cu+ in the catalyst could be adjusted,which is beneficial to the formation of MG.3.Preparation of Cu/CS-SiO₂ catalyst and application in DMO hydrogenation to MGThe preparation of Cu/CS-SiO₂ series catalyst is also prepared by ammonia evaporation,CS is carbon microsphere.This part of the work is to use carbon microspheres and SiO₂ as a double carrier and then loaded copper species.For this part of the work quality of Cu loading,different CS/SiO₂ mass ratio and liquid space vel?ity reaction conditions were investigated on the catalytic activity,which highlights the catalytic activity of 20%Cu/1CS-1SiO₂,the formation of ethylene glycol?EG?at low speed,the main product yield is 90%;high speed main product was MG,the yield of product is up to 60%,and the catalyst has a good stability.It was found that the structure of the catalyst was changed by CS-SiO₂ double carriers,and the effect of copper species on the dispersion and the content of Cu+ were also discussed.