Catalysts For The Selective Hydrogenation Of Methacrolein To Methyl Allyl Alcohol

Methallyl alcohol(MAO)is an important organic synthesis intermediates and raw material of fine chemicals,especially employed for HPEG synthses,which is the material for new kind of water-reducing admixture.Recent years,the requiment for the new water-reducing admixture increase about 20%.And more,MAO is expected as the replacement for ally alcohol,which is used widely in water-reducing admixture and is regared as a slight toxicity substance.The effects of active metal,additives and support of catalysts have been studied for the hydrogenation from methyl acrolein to methallyl alcohol under the fixed kettle type conditions,and the process parameters for catalyst praperation have also studied,2% Re-2% Ir/K004 catalyst has been developed with excellent performance.The strong intecation was proposed between ReOx and IrOx on catalyst,which lowered the reduction temperature and promoted the reaction performance.The acid site with proper acid strength was found to increase the production of MAO.The influence of process parameters on catalyst performance were studied in batch reactor.The promotion effect was found with water solvent in feed.The optimized reaction condition is as followed: rection temperature 70 °C,pressure 2 MPa,residence time 4 h,under which MAL conversion reached 79.4% with MAL selectivity of 56.3%.The hydrogenation of MAL to MAO was carried on 2% Re-2% Ir/K004 catalyst in bed reactor.Without water in feed,excellent reaction perfoance was maintained with MAL conversion of 58.7% and MAO selectivity of 34.9% under optimized reaction conditions.The difference between catalyst reaction performance in fixed bed reaction and that in batch reactor probably arise from the diffusion effects under the two reaction conditions.