CuCeZr Solid Solution Catalyst Catalyzes The Dehydrogenation Of Ethanol To Ethyl Acetate

Ethyl acetate is a significant organic solvent that finds extensive application in industrial production.Among the various methods employed for its preparation,ethanol dehydrogenation has emerged as one of the most competitive techniques owing to its high atomic economy（96%）,abundant availability of raw materials,and absence of waste acid and by-product hydrogen.The key to achieving an efficient method for ethanol dehydrogenation in the preparation of ethyl acetate lies in the design and precise regulation of catalysts.Cu Zr-based catalysts have been widely utilized due to their low toxicity,water resistance,and excellent catalytic properties.However,the uncontrollable catalytic microenvironment on the surface of Cu Zr-based catalysts results in a complex downstream conversion network for ethanol,leading to the formation of ethyl acetate accompanied by the production of aldehydes,ketones and other byproducts.Despite the significant challenges,achieving high efficiency ethanol conversion through selective preparation of ethyl acetate remains a critical objective.This paper presents an innovative approach to the ethanol dehydrogenation process of ethyl acetate,which involves starting with Cu Zr catalyst and modifying it through Ce doping.By designing and preparing a series of CuCeZr solid solution catalysts that control the number of active Cu sites and acid-base site strength,we were able to achieve highly efficient ethanol dehydrogenation for selective preparation of ethyl acetate.The structure-activity relationship was further established and the catalytic mechanism of principal and secondary reactions was clarified,providing reference for the further design and preparation of highly active catalysts.The specific research results are as follows:1)CuCeZr solid solution catalyst was synthesized by coprecipitation method,and the selective dehydrogenation condensation of ethanol to ethyl acetate was achieved.At 10 wt%Ce doping,the CuCeZr catalyst showed the highest selectivity for ethyl acetate（87.5%）and55.9%ethanol conversion,which was superior to other reported Cu Zr-based catalysts.The continuous 1000 h lifetime test results show that CuCeZr catalyst has good stability.The characterization and reaction results showed that the Ce doping promoted the formation of Cu（I）and improved the selectivity of ethyl acetate.In addition,it reduces the number of strong acid-base sites,inhibits the self-condensation and dehydration processes of acetaldehyde,and reduces the production of C4 by-products.2)Based on the basic understanding of the catalytic system,the influence of co-precipitation p H value on the catalytic performance of bioethanol dehydrogenation to ethyl acetate was investigated,and the reaction conditions such as reaction temperature,reaction pressure and mass space velocity were investigated and optimized.The results show that when the precipitation p H is 12,the catalytic performance of CuCeZr catalyst is the best.When the reaction temperature is 240℃,the reaction pressure is 1.0 MPa,and the mass space velocity is 1.0 h^-1,the conversion of ethanol and the selectivity of ethyl acetate reach45.6%and 80.6%,respectively.The results of 250 hours continuous stable operation show that the catalyst has good catalytic stability.