Study On The Catalyst For Preparation Of γ-Butyrolactone By Vaper-phase Dehydrogenation Of1,4-Butanediol

γ-butyrolactone （GBL） is an important fine organic chemical, drug synthesisintermediates and fine solvents, its industrial demand is very large. At present, the mostpopulous process of industrial production of γ-butyrolactone is vaper-phase1,4-butanediol （BDO） dehydrogenation process，and the key to this process is theexcellent performance of the catalyst. While the most commonly used Cu-based catalyststill has some problems, e.g. low yield of γ-butyrolactone, high content of poisous Cr.For preparing the catalyst with better performance, it is important to clarify theinfluence of the composition and structural properties on the performance of the catalyst,which has very important theoretical and practical significance for the developing newcatalysts, enhancing the catalytic dehydrogenation activity, ameliorating the processconditions, and increasing the yield of γ-butyrolactone.Cu/ZnO/Al₂O₃catalyst was firstly prepared by the co-precipitation method, andCu/Al₂O₃, ZnO/Al₂O₃catalyst was also prepared for comparison. The influence of theadditives Zn to the activity of BDO dehydrogenation on these catalysts was studied. Theresults of experiments showed that adding certain amount of additives Zn can increasesurface area of the catalyst and the dispersion of Cu, thus improves the selectivity ofGBL by preventing dehydration of BDO. Cu/ZnO/Al₂O₃catalysts with different Zncontents were characterized by XRD, BET, and TEM. The results showed that Cu/Znmolar ratio has a significant influence on the specific surface area of the catalyst anddispersion of Cu, which indicates that Cu and Zn can interact to form an active unit, sothat it was able to influence the performance of the catalyst. With the increase of Cu/Znmolar ratio, the specific surface area the catalyst and dispersion of Cu increased to amaximum and then decreased. And the selectivity of GBL also showed the same trend,which indicates the large surface area of the catalyst and good dispersion of Cu can helpimprove the performance of the catalysts. When content of Al₂O₃was20％（molarcontent） and Cu/Zn molar ratio was1, the catalyst had the maximum specific surfacearea, the best dispersion of Cu, and the best performance.Then, nano-TiO₂with high surface area was used as carrier for Cu-Cr/TiO₂catalysts, which was prepared by the deposition precipitation method. The influence ofthe additives Cr on the activity of BDO dehydrogenation on this catalyst and thecatalyst stability was studied. The experimental results showed that the conversion of BDO remains above99%, the selectivity of GBL remained above97%for48hr, whichindicates the Cu-Cr/TiO₂catalyst has high activity of1,4-butanediol dehydrogenationand good stability. XRD showed that additives Cr can interact with to form the CuCr2O4solid solution, thereby increasing the dispersion of Cu, and then enhancing the stabilityof the catalyst and the selectivity of GBL. The results of XRD, BET, and TEM of.theCu-Cr/TiO₂catalysts with different content of Cr showed that specific surface area ofthe catalyst and dispersion of Cu increases to a maximum and then decreased with theincrease of Cr contents, so does the selectivity of GBL. When the content of Cu is40wt%and Cr is3wt%, the catalyst shows the maximum specific surface area, the bestdispersion of Cu, and the best performance.