Preparation And Performance Study Of HF-Based Acid-Base Bifunctional Catalysts For Catalytic Transfer Hydrogenation Of Furfural

Due to the non-renewable and environmental pollution problems of traditional fossil fuels,the development of new energy-efficient,high-grade fuels and chemicals has become the focus of current scientific research.Biomass energy has the characteristics of renewable,abundant sources and low pollution,and has attracted extensive attention in recent years.Among them,lignocellulose can obtain a variety of oxygen-containing small molecule compounds through a series of catalytic conversions.These oxygen-containing compounds can be used as raw materials for further conversion into various fine chemicals and liquid fuels through hydrogenation and other means.Traditional hydrogenation conversion uses the H₂ as the hydrogen source,which has the disadvantages of transportation and storage difficulties,high cost,and flammability and explosion.Therefore,it is of great scientific significance and economic value to explore the liquid hydrogen source to replace hydrogen to achieve the catalytic transfer hydrogenation（CTH）of biomass derivatives.This paper studies the selective hydrogenation conversion of furfural（FUR）and studying preparation and catalytic performance of the used catalyst.Organic-inorganic hybrids are used as acid-base bifunctional hydrogenation catalysts,and organic alcohols are used as hydrogen sources.It also catalyzes the selective hydrogenation of furfural to furfuryl alcohol（FFA）.The acid-base active sites,conversion efficiency,product yield and selectivity of the catalyst were investigated in detail,and its catalytic mechanism,recycling performance and application prospect were discussed.The research results of this paper include the following aspects:The work was about preparation and performance study of bifunctional catalyst Hf-PDCA for catalytic hydrogenation of FUR.The organic-inorganic hybrid material Hf-PDCA catalyst was prepared by a simple and economic method,and applied to the efficient catalytic hydrogenation of FUR to produce FFA.The metal chloride（Hf Cl₄）and the organic ligand 1H-pyrrole-2,5-dicarboxylic acid（PDCA）were reacted to synthesize Hf-PDCA catalyst by hydrothermal method.The as-prepared Hf-PDCA was characterized by various characterization techniques.It was proved that the Hf-PDCA catalyst was a porous,nitrogen-containing,heterogeneous acid-base bifunctional catalyst.The as-prepared catalyst exhibits excellent catalytic performance in the catalytic hydrogenation of FUR.FUR conversation（98.8%）,FFA selectivity（98.5%）were obtained from FUR over Hf-PDCA using 2-propanol as the hydrogen source under mild conditions（120oC,2 h）.The catalyst can also be recovered by filtration and washing after the end of the reaction.The catalytic performance of the catalyst hardly changes after repeated use for six times,indicating that the Hf-PDCA catalyst has strong stability and durability.In addition,the catalyst is also extended to the preparation of corresponding alcohols by the hydrogenation reaction of other biomass derivative aldehydes,and it also shows good catalytic activity.The work was about preparation and performance study of bifunctional catalyst Hf-H₃IDC-T for catalytic hydrogenation of FUR.In the above work,we found that the nitrogen-containing heteroatom group in the organic ligand structure can promote the hydrogenation reaction.In addition,in order to further improve the catalytic performance of the catalyst,it is necessary to increase the specific surface area of the catalyst.Based on this,we have further optimized the preparation of catalysts and the selection of organic ligands.We have optimized the preparation of the catalyst.The Hf-H₃IDC-T hydrogenation catalyst was prepared by hydrothermal method under the ideas of the previous work.Herein,a facile route was developed to synthesize the surfactant-assisted heterogeneous acid-base bifunctional 4,5-imidazoledicarboxylic acid-hafnium hybrid catalyst（Hf-H₃IDC-T）by hydrothermal reaction method.The as-prepared Hf-H₃IDC-T was characterized in detail.Hf-H₃IDC-T hybrid had mesoporous structure and acid-base couple sites.The experimental results show that a quantitative yield（99.2%）of FFA was obtained from FUR over Hf-H₃IDC-T using 2-propanol as the hydrogen source under mild conditions（120oC,1 h）.It’s found that the amino groups on the imidazole ring are beneficial to enhance the base sites of catalyst.Meanwhile,the addition of CTAB as template agents can improve the specific surface area of the catalyst.Dynamic analysis showed that the apparent activation energy of FUR reduction was as low as 50.89 k J/mol.The as-prepared catalyst has good stability and can be recycled.Finally,the catalyst also has a good catalytic effect on the hydrogenation reaction of aldehydes and ketones of biomass-derived compounds.