Total Hydrogenation Of Furfural To Tetrahydrofurfuryl Alcohol Under Mild Conditions

Furfural is one of the platform compounds which is derived from the hemicellulose biomass.The catalytic conversion of furfural to useful chemicals has attracted tremendous attentions in both academic and industrial research fields.This thesis focuses on the total hydrogenation of furfural to tetrahydrofurfuryl alcohol.Two strategies have been employed for this purpose.First,physical mixture of supported Pd and Ru catalysts on various supports have been prepared and their catalytic performances in total hydrogenation have been evaluated.Second,monometallic Pd supported on CeO₂ with different morphologies have been synthesized and used as the catalysts for total hydrogenation.The major results have been summarized as following:The total hydrogenation of furfural in aqueous solution was investigated under mild conditions over a series of physical mixture of Pd and Ru supported catalysts.When supported Pd and Ru catalysts were mixed,the yield of tetrahydrofurfuryl alcohol was significantly improved compared with monometallic catalysts.A support-dependent promotion effect was noticed,in particular,Pd/Al₂O₃ and Ru/ZrO₂ mixture gave 99%yield of tetrahydrofurfuryl alcohol at 30°C and 0.5 MPa H₂.Detailed kinetics studies suggest that the reaction pathway with tetrahydrofurfural as the intermediate could be involved in this process.The apparent activation energy of furan hydrogenation over Pd/Al₂O₃ and the subsequent C=O bond hydrogenation over Ru/ZrO₂ is about 21 and30 kJ/mol,respectively.The low activation energies may well explain the observed activity of total hydrogenation of FAL over bimetallic mixtures.Pd/CeO₂ exhibited better performance for the total hydrogenation of furfural compared with Pd/Al₂O₃ and Pd/SiO₂.H₂-TPR profiles of CeO₂ with various morphology and corresponding Pd/CeO₂ suggest that the strong metal-support interaction between Pd and CeO₂ surface promotes the total hydrogenation activity.This enhancing effect depends on the morphology and particle size of CeO₂ materials.Pd supported on nanorod CeO₂ with diameter about 10 nm by using concentrated NaOH solution as base shows the best performance with 96%yield of tetrahydrofurfuryl alcohol under 50°C and 0.5 MPa of H₂ pressure within 2 hours.