Selective Hydrogenation Of Furfural Over Raney Copper Catalyst

Furfural is an important organic chemical material.Furfural is a very reaetive molecule because of its unsaturated carbon-carbon double bonds in the furan ring and the carbonyl in the side chain,so a large number of derivatives can be obtained by catalytic hydrogenation,such as furfuryl alcohol,2-methyl furan,cyclopentanone and cyclopentanol.Present traditional catalyst for furfural hydrogenation contains Cr is harmful to people's health and causes severe environmental pollution.So to study new high active catalyst for hydrogenation of furfural,is no doubt of great practical significance.The Raney catalyst was prepared by quenching technique,and it was employed for the catalytic hydrogenation of furfural.Effects of solvent type,volume ratio of solvent,volume ratio of reactants and solvent,reaction temperature,reaction pressure and reaction time on the furfural conversion and selectivity are investigated in detail.Under the optimal conditions(V(methanol):V(water)=4:1,V(furfural):V(solvent)=1:10,180 ?,3MPa and 4 h),the conversion of furfural is 98.9% and the selectivity of cyclopentanone and cyclopentanol are 52.9% and 19.3% respectively.The microstructure of Raney copper is characterized by XRD,BET and SEM.Then a possible reaction mechanism of hydrogenation of furfural to cyclopentanone and cyclopentanol was put forward.On the basis of catalytic hydrogenation system of furfural catalyzed by Raney copper,effects of Cu2 O which contain in the Raney copper was investigated in detail.The Raney copper was processing by acetic acid and ammonia.The content of Cu2 O in the Raney copper reduced and the conversion of furfural was improved after processing by acetic acid and ammonia.This suggests that Cu2 O restrain the hydrogenation of furfural.Then the Raney copper modified by metal elements was employed for the catalytic hydrogenation of furfural.The structural characterization of the catalysts indicated that the Raney copper modified by phosphotungstic acid and nickel nitrate cotain less Cu2 O,the conversion of furfural was higher and the main products was cyclopentanone and cyclopentanol.