Preparation And Characterization Of Pd/C Catalysts And Their Application In Hydrogention Of Dehydrodibenzylbiotin-methyl Ester

Recently,Biotin(VH)which is widely used in the pharmaceutical,health-product,food and cosmetic industry becomes a major concern.The hydrogenation of dehydrodibenzylbiotin-methyl ester is the important step of the technology for Biotin.This process is widely used by domestic and foreign companies.However,the catalysts used for the hydrogenation of dehydrodibenzylbiotin-methyl ester by some domestic companies currently have some characteristics as low activity and stability,resulting in a high manufacturing cost.Therefore,the main objective of this research is to develop a catalyst with high activity for the hydrogenation of dehydrodibenzylbiotin-methyl ester in order to reduce the production cost.Pd/C catalysts were prepared by a wet-impregnation metnod.On the basis of screening appropriate activated carbon as support,catalysts preparation conditions,including nitric acid pre-treatment with activated carbon,etc.were optimized.N2 adsorption-desorption,XRD,TEM ect.were applied to characterize activated carbon supports and catalysts,and then the prepared catalysts were used in the hydrogenation of dehydrodibenzylbiotin-methyl ester.The catalysts developed in lab were used on a pilot scale at the collaborated companies.The results showed that the catalyst showed a better performance than the product bought from market.This catalyst can significantly reduce the production cost.The catalystic kinetics of the hydrogenation of dehydrodibenzylbiotin-methyl ester over the developed 7.5%Pd/C were studied in batch reactions.Influencing factors such as stirring speed,Pressure of H2,temperature and dosages were studied.In the end,the poisoning mechanism of the catalysts was summarized in the hydrogenation reaction,and the methods to resistance poison were put forward.