Synthesis Of Carbon Supported Pd-based Catalyst And The Application In Hydrogenation

Hydrogenations are one the pillars of the chemical industry.Synthesis of high performance catalysts to improve the selectivity of the hydrogenation reaction has always been the core content of scientists' research.Carbon supported Pd-based catalysts are the most widely used catalysts in industrial hydrogenations,especially in the field of fine chemicals.Therefore,it is necessary to study the carbon supported Pd-based catalysts with high activity,selectivity and stability for fine chemical industrial application.This work focuses on the preparation of carbon-supported palladium-based catalysts which can be applied in industry,and the catalytic performance in varieties practical hydrogenation reactions.In addition,the synthesis process of m-nitroaniline by catalytic hydrogenation was studied.Main reseach findings have been summarized as following:Chapter 1:Summarized the synthesis process of aromatic amine intermediates and the importance of selective hydrogenation.Strategies of improving hydrogenation selectivity and the recovery process of stannous chloride in industry were also introduced.The meanings and content of this thesis were listed.Chapter 2:CO and H2O are used as reductant to synthesize Pd/C catalyst under different conditions.And the performance of the catalysts in the hydrogenation reaction were investigated by the hydrogenation of styrene as the probe.The optimum preparation condition of Pd/C was screened out and the prepared Pd/C catalyst was successfully applied into the recovery process of stannous chloride by catalytic hydrogenation.Chapter 3:A bimetallic catalyst was prepared by introducing Ru into Pd/C catalyst.The bimetallic catalysts with different loading and different molar ratios of palladium and ruthenium were synthesized by coprecipitation method,and their catalytic performance in hydrogenation of nitrobenzene and o-nitroaniline was studied.The result showed that the catalyst with 1%Pd loading and 4%Ru loading has favorable performance in the hydrogenation of nitro group,which was superior to commercial Pd/C catalysts.In addition,the prepared Pd1Ru4/C catalyst also has a good performance in the synthesis of hydrogenated rosin.Chapter 4:A process route for the preparation of m-nitroaniline by selective hydrogenation of m-dinitrobenzene was developed.The yield of,m-nitroaniline products reached more than 90%through controlling the end point of reaction and selecting the appropriate catalyst and catalytic additives,was superior to traditional synthesis process.This result brings new opportunities for the industrial green synthesis processes of m-nitroaniline.Chapter 5:Conclusions and prospects of the mechanism and application of carbon-supported palladium-based catalysts are given.