Chloride-free Copper Catalyst Prepared By Liquid-phase Reduction Method And Oxycarbonylation Catalysis

Dimethyl carbonate (DMC) is an environment benign green-chemical which regarded as"new elementary-block"has wide application prospects because of its low toxicity and extensive dustry application. Among all methods, vapour phase carbonylation route is beneficial in thermodynamics therefor be focus as its simple process, environmental beingn and low cost. Metal choloride are selected as the precursor of these catalysts in presently study, thus the problems caused by chlorin lose of catalyst are mostly unavoidable, the research shows that the quick deactivation results in short longevity and HCl produced bring in heavy corrosion on equipments during the DMC synthesis process due to losing Cl from the catalyst. Therefore,the chloride-free catalyst become the important research direction. King prepared chloride-free catalyst Cu2O/LZ-20M(HAR) reach the high activity of CuCl/LZ-20M. Drake prepared chloride-free Cu/SiO2 catalysts with superior catalytic activity than the Cu(NO3)2 catalyst prepared by immersion method, these results show that Cl is unnecessary for DMC synthesis. Richter prepared chloride-free Cuâ… /Y zeolites catalysts, which were used Y zeolite impregated in the solution of Cu(NO3)2 or Cu(CH3COO)2, then heat-treated promote reduction of CuO dispersed on the surface of zeolite Cu2+ to Cu+.Our team once prepared the Cu/zeolite catalyst via SSIE(solid state ion exchange) by heating the mixed sample of CuCl or CuCl2 with zeolites, and prepared supporting Cu2(OH)3Cl catalyst by aqueous treatment to relief the problems caused by chlorine lose. And finally, the Cu2O/AC catalysts has good oxycarbonylation performance which prepared by pyrolysis of copper acetate dispersing in the surface of supports. This thesis is aimed at prepare chloride-free catalyst and changing the copper valent by adding reducing agent in liquid phase. the catalytic activities of Cu2O supported were studied on oxidative carbonylation of methanol to dimethyl carbonate, the effects of reducing agent, copper salt precurs, copper contents, precipitator, support and support modification were investigated. Also XRD, TPR, IR and SEM chacterization means were used to study these catalysts. After comparing the results of evaluation and characterization, the conclusions were listed as follow:(1) Prepared Cu2O/AC catalyst by liquid-phase reduction method.The effect of preparation condition, support and Cu2O laoding amount were investigated. The result: Under the normal condition, active carbon as support, catalyst show best performance when Cu2O laoding amount was 17.3%.(2)Reducing agent is the main factor which effect active species when glucose as reducing agent and dosage is 4g, Cu2O particle was global and its size small; precipitator doesn't change catalyst structure and performance, only provide alkaline condition; Copper salt precursor had greatly influence on catalyst performance, copper acetate is the best of we tested. The average STY of first 9 hours was to 71.96 mg?g-1?h-1. The reason of catalyst deactivation is not active species but for Cu2O particle dimeter grow up.(3)Hydrogen peroxide modified active carbone make the quantities of C=O bond increased, so hydrogen consumption increase obviously. This change can promote combine between Cu2O and support result in activity improvement.