Preparation Of Bimetallic Catalysts And Their Performance In Catalytic Hydrogenation Reactions

Catalytic hydrogenation is one of the most important reactions in fine chemical industry.In fine chemical industry,some chemical pollutants can be converted by hydrogenation to purify the environment,and more valuable chemicals can be produced than substrate molecules.Therefore,catalytic hydrogenation technology can bring considerable benefits in environment and economy.The development of catalytic hydrogenation technology is mainly limited by low conversion rate of substrate molecules and selectivity of target products.Thus,research and development of high efficient catalyst is the key to promote the development of hydrogenation technology.At present,metallic catalysts are prevalent in research.Compared to mono-metallic catalysts,bimetallic catalysts often have more excellent catalytic hydrogenation performance because of the synergistic effect between metals.In this paper,bimetallic catalysts Ru Pt/C,Ru Cu@C were successfully synthesized and used in semi-hydrogenation of phenylacetylene,hydrogenation of 4-nitrophenol and furfural The catalytic hydrogenation performance under different conditions and mechanism of the catalysts were systematically studied.The main contents are as follows:（1）Ru/C,Pt/C and Ru Pt/C catalysts were prepared by solvothermal method.Ru/C showed low catalytic activity and high selectivity of styrene in semi-hydrogenation reaction of phenylacetylene,while Pt/C had high activity and low selectivity.In contrast,Ru Pt/C showed both high activity and selectivity due to the synergistic action of bimetal.In hydrogenation of4-nitrophenol to 4-aminophenol,Ru Pt/C showed a higher catalytic activity than that of mono-metal catalyst.Besides,catalytic activity of Ru Pt/C showed no decrease after 5 cycles.The excellent catalytic performance of Ru Pt/C catalyst can be attributed to the synergistic effect of bimetal Ru Pt.（2）Ru Cl₃ was loaded on Cu-BTC（1,3,5-benzenetricarboxylic acid,copper salt）and then pyrolyzed in N₂ at 500℃to obtain Ru Cu@C catalyst.When used in hydrogenation rearrangement of furfural,it was found that the introduction of Ru increased the selectivity of cyclopentanone compared with Cu@C.And reaction temperature,hydrogen pressure,concentration of furfural and solvent all affected the distribution of reactants in hydrogenation and rearrange of furfural.When 1.5%Ru Cu@C was used as catalyst,the reaction temperature was 150℃,the hydrogen pressure was 3 Mpa,the furfural concentration was 0.3 mol/L,and toluene/water was used as solvent,the furfural was completely transformed and the selectivity of cyclopentanone was 62%.Kinetic studies showed that intermediates such as furfuryl alcohol,4-hydroxy-2-cyclopentenone,3-hydroxy-cyclopentenone,2-cyclopentenone would be produced successively,and then cyclopentenone was formed.In addition,the Ru Cu@C catalyst showed good stability when reused in hydrogenation of furfural to cyclopentanone.