Studies On Hydrogen Transfer Reaction Of Aromatic Over Supported ZrO₂ ZrMO_x?M=La?Ce?Sm?Gd?

Aromatic alcohol is a kind of important chemical intermediate,and the Meerwein-Ponndorf-Verley(MPV)reduction offered a viable route for hydrogenation of aromatic ketone,with the advantages of high chemical selectivity,mild conditions and simple treatment after reaction.Zirconia supported on activity carbon,siliceous MCM-41 mesporous and silica gel,respectively,was prepared through the method of impregnation,and the ZrMOx/MCM-41 was also by this way.Their activities in the MPV reduction of acetopheone with ?-propanol as a hydrogen donor were investigated.At the same time,these samples were characterized by XRD,N2 adsorption-desorption,XPS,TG-DSC,NH3-TPD,FT-IR spectra of adsorbed pyridine methods.The results showed that catalytic activity was significantly improved upon loading Zirconia on MCM-41 and silica gel,and the Zr02/MCM-41 showed better catalytic activity than the ZrO2/SiO2,due to the highly dispersion of Zr02 on MCM-41.There was no obvious increase of catalytic activity after loading Zirconia on AC support,owing to the weak interaction between Zirconia and AC support.The best loading of ZrO2/MCM-41 was 5%.The reaction was essentially completed after 8h;The best alcohol-ketone ratio was 10:1;Compared with acetophenone,the conversion of acetophenone with electron-withdrawing grounp linked to the aromatic ring was higher,while the conversion of acetophenone with electron-releasing grounp linked to aromatic ring was lower.The addition of lanthanide elements and the loading order had important influences on the catalytic activities.The catalytic activity was significantly improved upon La and Sm addition to the catalyst,the catalytic activity was slightly improved by adding the Gd to the catalyst,and when the Ce added,the catalytic activity fell sharply.ZrO2-La2O3/MCM-41 and Sm2O3-Zr02/MCM-41 were the best preparation method.The optimal loading amount of La2O3 on ZrMOx/MCM-41 was 3%,and the Sm2O3 was 5%.The reaction was essentially completed after 8h;The best alcohol-ketone ratio was 10 · 1;Compared with acetophenone,the conversion of acetophenone with electron-withdrawing group linked to the aromatic ring was higher,while the conversion of acetophenone with electron-releasing group linked to aromatic ring was lower.The order of the catalysts'reusability was 5%Zr02/MCM-41>5%Sm203-5%Zr02/MCM-41>5%Zr02-3%La203/MCM-41,and the order of the catalysts'water-resistance was 5%Zr02-3%La203/MCM-41>5%Zr02/MCM-41>5%Sm203-5%Zr02/MCM-41,and the order of acid resistance or base resistance of the catalysts was 5%Zr02/MCM-41>5%Zr02-3%La203/MCM-41>5%Sm203-5%Zr02/MCM-41 or 5%Zr02-3%La203/MCM-41>5%Zr02/MCM-41>5%Sm203-5%Zr02/MCM-41.