Study On Copper-based Hydrogenation Catalyst For Synthesis Of DL-γ-Butyrolactone

α-Hydroxy-β,β-dimethyl-γ-butyrolactone(DL-γ-butyrolactone) is an importantintermediate for preparation of series products, i.e., pantothenic acid. As the developmentof living condition, the applications of pantothenic acid series products increase in dailychemical, meanwhile DL-γ-butyrolactone demand expands ceaselessly. The synthesis ofDL-γ-butyrolactone contains aldol reaction, hydrogenation and lactonization cyclizationreaction. Among which hydrogenation catalyst of higher activity is the key to the study.In this paper, the copper-based catalyst was prepared by precipitation method. Theeffects of different precipitants and precipitation methods on the activity of hydrogenationcatalyst were studied. The best activity of copper-based catalyst was obtained by NaOHas precipitant and prepared by parallel flow co-precipitation method. The influences ofreaction temperature, pressure of H2, molar ratio of hydrogen and aldehyde and liquidspace velocity on hydrogenation process for synthesis of DL-γ-butyrolactone incontinuous micro-fixed bed reactor were also investigated. The obtained optimumreaction conditions were as following: reaction temperature120℃, hydrogen pressure7MPa, n(hydrogen):n(aldehyde)=80:1and liquid hourly space velocity0.6~0.8h-1.Under above-metioned conditions, the yield of product was up to98%.In order to obtain better stability of copper-based catalyst, changing the carrier andadding different additives to hydrogenation catalyst were studied. The results showed thatthe activity of hydrogenation catalyst decreased when changed carrier by adding Al2O3to copper-based catalyst, while high activity and better stability of catalyst were obtained by adding Ni and Mn to modified copper-based catalyst. The structure and morphology ofthe catalyst were characterized by XRD, TPR, BET and SEM. The results fromcharacterization indicated that the increase of surface area and pore volume and thedecrease in diameter of the active particles which resulted from the introduction of Ni andMn, are good for the improvement of catalytic activity and stability.After the scale-up of catalyst preparation process, on the basis of previous studies inthe laboratory, there was no changes on activity,crystal form and BET area of catalyst,which means the effect of saling-up was eliminated effectively. A high repeatability wasalso observed in the preparation of the catalyst.