Hydrogenation Of Biomass-Derived Aldehydes And Ketones Over Supported Cobalt-based Catalysts

By the development of science and technology,and the increasing material needs of people,the way of energy-providing on the earth has changed.Developing new energy sources is of great significance to the world's sustainable development due to the non-renewability of traditional petrochemical resources and a series of environmental problems caused by its use.As one of the most abundant resources on the earth among many renewable resources,biomass can be used in the fields of energy and chemical industry,and has a broad prospect of replacing traditional fossil energy.Therefore,it has received extensive attention and research.Lignocellulose biomass is very abundant,with an annual output of about 200 billion tons,making it the most promising alternative to fossil resources.Through the utilization of lignocellulose,a range of biomass platform molecules,such as high-value chemicals and fuel additives,can be prepared.These platform molecules can be directly applied or further catalyzed into other important molecules.Therefore,the research of depolymerizing biomass and the catalytic conversion of platform molecules have strategic significance.There have been many research results of catalytic conversion of biomass platform molecules in the past decades.For the hydrogenation catalysis of platform molecules,the conventional methods mostly used precious metal catalysts which cost too much.Meanwhile,most of the catalytic reactions needed to be in an organic solvent,and the subsequent separation was relatively difficult and easily caused various environmental problems.Therefore,we have developed a new hydrogenation catalytic system using cobalt as the catalytically active metal,zirconium dioxide and rare earth metals as carriers to efficiently catalyze the selective hydrogenation of aldehydes and ketones in the aqueous phase,and catalytic activity was superior to commercial precious metal catalysts.Meanwhile,the catalysts were stable during the reaction and well tolerated.In our first work,we used yttria-modified zirconia as a carrier,supported cobalt metal,and completely converted furfural under the reaction conditions of 80 ?,2 MPa hydrogen,2 h,and water as solvent.The yield of the sterol product was 98%.In addition,the catalyst still had catalytic activity after 5 cycles,and the yield of sterol was still above 95%.Through a series of characterization techniques and comparative experiments,we found that the excellent catalytic activity of the system is attributed to the strong interaction between the loaded metal and the carrierBased on the first work,we found that the making the rare earth metal directly as a catalyst carrier also exhibited good reactivity,and the catalyst preparation of this system was more simple,which was also suitable for the hydrogenation reaction of biomass platform molecules.We selected ethyl levulinate to prepare ?-valerolactone as a model reaction,and investigated the hydrogenation activity of a series of Co/La catalysts with different preparation conditions,and found that the addition of Bronsted acid promoted the reaction.At 90 ?,4 MPa hydrogen,4 h,water as a solvent,under the reaction conditions of HZSM-5,ethyl levulinate was completely converted,and the yield of y-valerolactone was over 99%,which was characterized by a series of Technical and comparative experiments,we found that the excellent catalytic activity of the system is attributed to the proper acidity and alkalinity of the carrier and the addition of Bronsted acid to the conversion of the intermediates of the reaction.