Pd-non-precious Metal / C Catalysts Of Hydrogenation Of Maleic Anhydride System Tetrahydrofuran

The effect of non-noble metal component M (herein M represents one or more non-noble metal elements) on the performance of Pd-M/C catalyst for the hydrogenation of maleic anhydride (MA) to tefrahydroftiran (ThF) was investigated under moderate pressure (2.O-8.OMpa) in a fixed-bed microreactor '~' -butyrolactone (GBL) or maleic anhydride as a feedstock. It is found that the performance of the Pd-M1C catalyst for the hydrogenation of MA was significantly improved when the Pd-M/C catalyst was prepared by impregnating the Pd/C with a mixed salt solution containing four non-noble metal Cu, Zn, Mn, and Al.The concerted catalysis between copper, zinc, manganese, aluminum and palladium was investigated carefully. The addition of manganese and aluminum to Pd/C catalyst increases the activity of hydrogenation, the addition of zinc and copper improves the selectivity of THF.When the Pd-M/C catalyst was used for hydrogenation of MA, the reaction pathway was in accord with that hypothesis of Massimo Messori. In the Pd-M1C catalyst system, the most of THF was from form the pathway of MA-GBL- BDO-THF.The structure of Pd-M/C catalyst was examined by using techniques of SEM, TEM, XPS and XRD. The main factors influencing the catalyst structure were investigated. The effect of catalyst structure on catalyst performance was discussed. The spherical particles of catalyst active components highly dispersed on the support of active carbon are advantageous to improving the performance of Pd-M/C catalyst Calcining temperature is an important factor of affecting catalyst stmcture, and it is preferably in the range from 4OO-5OOC. The ammoniation of Pd-M1Ccatalyst can improve the catalyst active components to form highly dispersed spherical particles on active carbon.