Study The Effect Of Cu-based Hydrotalcite Catalyst On The Hydrogenation Of Furfuralcohol To Pentanediol

1,2-pentanediol and 1,5-pentanediol are widely concerned as the important diols and crucial intermediates in organic synthesis.1,2-pentanediol is an important pharmaceutical and chemical intermediate for the synthesis of fungicide propionazole.Moreover,it is also an important raw material for the production of polyester fiber,surfactant,printing ink,cosmetics and medicine,etc.1,5-Pentanediol is a linear diol that is widely used as a chemical intermediate in the manufacture of coatings,polyesters,perfumes,polyurethanes,plasticizers,and inkjet inks or inks.Recently,the demand for pentanediol has growing rapidly as the well prospect of its market.However,there is a large gap in domestic production for pentanediol.It is hence that the efficient synthesis of pentanediol has broad development prospect and application value.At present,pentanediol is mainly obtained by the hydrogenation of biomass-based platform compound furfural or its downstream furfuryl alcohol.However,the existing technologies still have some problems,such as low catalytic efficiency,high production cost,harsh catalytic reaction conditions,and low yield of products.On the basis of these understandings,,a series of Cu-based hydrotalcite catalyst with high dispersion of active metal and alkaline prepared by coprecipitation were proposed for the hydrogenation of furfuryl alcohol to 1,2-pentanediol and1,5-pentanediol.Herein,the effects of different calcination temperatures and various Ce content on the catalyst structure,properties and catalytic performance were systematically investigated.Then the structure-activity relationship of the catalyst was established.The main contents of in this thesis are as follows:(1)In view of the low catalytic activity,high cost and low product yield,a highly efficient and stable metal-alkali bifunctional Cu Mg Al hydrotalcite catalyst was designed and prepared for the hydrogenation of furfuryl alcohol to pentanediol under mild conditions.The effects of catalyst calcination temperature on the structure,morphology and catalytic performance of the catalyst were investigated systematically,and the structure-activity relationship of the catalyst was established.The results show that the calcination temperature has a significant effect on the structure and catalytic performance of the catalyst.The metal active center and the basic site of the metal increased firstly and then decreased with the increase of the calcination temperature.The evaluation results diaplayed that the Cu-based hydrotalcite catalyst has high catalytic activity and selectivity for the hydrogenation of furfuryl alcohol.The surface of the catalyst,which calcined at 600℃ with a Cu content of 10%,has a suitable metal sites and basic sites,and exhibits excellent catalytic performance.Under the reaction temperature of 140℃ and H2 pressure of 4 MPa,the conversion of furfuryl alcohol and the yield of pentanediol reached 74.13%and 58.36%,respectively within 8h.(2)Based on the understanding of the first part,in which the synergistic effect between metal sites and base sites can promotthe efficiency of hydrogenation of furfuryl alcohol to pentanediol,the lanthanide element of Ce was introduced into the Cu Mg Al hydrotalcite catalyst.On the one hand,the addition of Ce might promote the reduction of metallic Cu;on the other hand,the surface alkalinity of the catalyst can be further increased with the addition of Ce.It is thus that the catalytic performance of the catalyst can be further improved in the hydrogenation of furfuryl alcohol to pentanediol.The effects of the Ce content and calcination temperature on the structure,properties and catalytic performance of Cu Mg Al Ce hydrotalcite catalyst were investigated systematically.The results show that the surface of the catalyst has the suitable metal sites and basic sites when the catalyst calcined at 500℃ with a 4:1 molar ratio of Cu/Ce.It exhibited an excellent catalytic performance under mild conditions as the synergistic effect between metal and alkaline sites.The conversion of furfuryl alcohol and the yield of pentanediol were up to 65.27% and 54.52%,respectively at 120℃ and the H2 pressure of 4 MPa within 8h,which has significant advantage over the catalyst without Ce.The research in this paper will provide a useful reference for the design of dual-site catalysts and provide new ideas for the efficient conversion of biomass.