| γ-Butyrolactone (GBL) is an important fine chemical which is widely used in petrochemicals, textile, pharmacentical and pesticide industries.There are inevitable deficiencies present in the traditional individual hydrogenation of maleic anhydride (MA) and dehydrogenation of 1,4-butanediol (BDO) process, such as poor utilization of hydrogen, low selectivity of the desired products and difficulty in controling process conditions. In order to solve these problems, the coupling process of hydrogenation of MA with dehydrogenation of BDO has been studied for the synthesis ofγ-butyrolactone.The preparation methods of catalysts were investigated in this paper. The results showed that the catalysts made by the co-precipitation and complex-precipitation methods both had good catalystic performance. The experiment results on the effect of the ratio of Cu/Zn/Al showed that the catalysts with 20% (molar content) Al and Cu/Zn molar ratio with a range of 0.5 to 2 had good catalytic performance.The results of experiments showed that ZnO could increase the selectivity of GBL by preventing dehydration of BDO. The characterization of catalysts using XRD, TPR and BET indicated that with the addition of ZnO, advantages such as increased specific surface area of the catalyst, lower reduced temperature and dispersion of CuO were found.The conditions of the coupling process were studied by orthogonal experiments. The effects of temperature, liquid space velocity (LSVH) and H2/C4 molar ratio were discussed. It was found that these factors did not have considerable influence on the conversion of BDO, instead, on the selectivity of GBL. The H2/C4 ratio and temperature factors had notable influences on the selectivity of GBL. The optimized reaction conditions were at temperature 240℃, LSVH 0.12h-1 and H2/C4 ratio 50.The results of TPSR showed that H2 was not only favorable to dehydrogenation of BDO, but also to the prevention of the dehydration of BDO and hydrogenolysis of the reactant.
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