Study on the selective hydrogenation of acetic acid to ethanol

Effects of temperature, pressure, acetic acid (HAC) feeding rate and H₂/HAC (GHSV or H₂ flow) on the conversion of acetic acid, product selectivities and the productivity of ethanol in selective hydrogenation of acetic acid to ethanol were investigated in a fixed-bed reactor. The good stability of the lab-made catalyst was verified. The results show that the reaction rate of esterification and decarboxylation/ketonization are very fast. Selectivities of ethyl acetate and acetone are affected by the catalyst composition and reaction conditions. The hydrodecarbonylation of acetic acid to methane and the further conversion of ethanol can be avoided when the contact time of the reactants with the catalyst is less than 5 s. Optimum reaction conditions were found at 280 ℃, 2.5 MPa, LHSV=0.72 h^-1, H₂/HAC (mol ratio)=16, under which the selectivity of ethyl acetate could reach 6%.Life time test more than 900 h shows that the lab-made catalyst has a good potential for industrial application.