Research Of Catalytic Hydrogenation Of Esters To Alcohols

The mixed dibasic acids, which are difficult to separate, are byproducts of the production process of adipic acid. It is not only a serious waste of resources, but also cause environmental pollution to throw the mixed dibasic acids away. Taking the mixed dibasic acids esterification,then catalytic hydrogenate these esters to alcohols, which are important chemical raw material of the products, has broad prospects.Prepared four copper-based catalysts by coprecipitation. Selected the Cu-Zn-Al catalyst as the hydrogenation catalyst by the pre-experiment. Identified the amount of catalyst is 5% of the fatty acid esters based on the weight.Considering the synthesis of esters and the process of catalytic hydrogenation, fatty acid dibutyl ester was selected as the hydrogenate material. Examined a variety of process conditions on the reaction. Experimental results showed that high temperature or high pressure was helpful for improving the conversion rate of esters, but the selectivity of alcohols would be debased when the temperature was too high. There was an optimal value of reaction time, the reaction was not sufficient when the time was too short, the target product turn to byproducts when the time was too long.The optimal reaction conditions of dibutyl succinate catalytic hydrogenation were optained:T= 270℃,P=11MPa, t=7h, the conversion rate was 95.23%,the yield of 1,4-butanediol was up to 56.14%.Within the reaction conditions, the conversion rate of dibutyl glutarate was up to 15.42%, while the yield of 1,5-pentanediol was very low.The optimal reaction conditions of dibutyl adipate catalytic hydrogenation were optained:T= 285℃, P=11MPa, t=6h, the conversion rate was 98.22%,and the yield of 1,6-hexanediol was up to 45.34%.