Selective hydrogenation of dimethyl maleate to tetrahydrofuran over Cu/SiO_2 catalyst:Effect of Cu^+ on the catalytic performance

摘要

Cu/SiO_2 catalysts prepared by different methods have been investigated focusing on the influence of Cu^+on the catalytic performance.The composition,structure and copper valence state were characterized by means of BET,XRD,XPS,FTIR,N_2O-titration.It was found that the Cu/SiO_2 prepared by ammoniaevaporation(AE) method had much higher TOF value than that prepared by wetness-impregnation(WI)with the same THF selectivity.The higher TOF value was attributed to the coexistence of Cu^+ and Cu^0species in the activated AE-Cu/SiO_2.while only Cu° species existing in the activated Wl-Cu/SiO_2.Researches suggest that Cu^+ can adsorb and polarize the C=0 bond of DMM.It is concluded that Cu°could be the main active site and the synergistic effect between Cu^0 and Cu^+ could contribute to hydrogenation of DMM to THF.