Maleic Anhydride At Atmospheric Pressure Hydrogenation Of ¦Ã-butyrolactone Catalyst

γ-Butyrolactone (GBL) is an important fine chemical intermediate, widely used in petrochemicals, textile, pharmaceutical and pesticide industries.γ-Butyrolactone is mainly synthesized from 1,4-butanediol dehydrogenation in industry. Due to the significantly reduction of maleic anhydride cost and the empty waste of H2 in chlor-alkali industry, malefic anhydride hydrogenating toγ-Butyrolactone was much concerned. However, the low activity, unstable selectivity and short life of the current industrial catalyst used in maleic anhydride hydrogenation have been seriously restricted the application of the method. Herein, the catalyst on maleic anhydride hydrogenation ofγ-butyrolactone was systematically studied.A series of Cu/ZnO, Cu/ZnO-SiO2, Cu/ZnO-Al2O3 and Cu/ZnO-C catalysts was prepared by means of parallel flow co-precipitation method. The carriers of catalysts were screened. The results showed that the activated carbon as carrier in Cu/Zn catalyst could lead to larger specific surface, better distribution of the active component and wider mesoporous distribution as well as lower reduction temperature of the catalyst. With the Cu/ZnO-C catalyst, the temperature of maleic anhydride hydrogenation toγ-butyrolactone could be decreased to 250℃which was 20~30℃lower than the industrial value. By optimizing the ratio of each component, the best mole ratio of Cu:Zn:C(active carbon) was between 2:2:1 and 2:2:2. The catalyst preparation conditions were studied. The results showed that the catalyst calcining temperature could affect specific surface, mesoporous distribution, reduction temperature, which affect the performance of the catalysts. According to catalyst characterization and catalytic activity of inspection data to determine the calcination temperature to 350℃for the best. Catalyst reduction temperature was 230℃under a mixture gas of 5% H2&N2.Catalytic reaction conditions were optimized. At the optimum condition, which temperature was 250℃, LHSV was 0.1h-1 and ratio of H2/MA was 50, the conversion of maleic anhydride was 100%, selectivity ofγ-Butyrolactone was more than 90% as well as succinic anhydride was not detected. Catalyst lifetime was investigated. The Cu/ZnO-C catalyst showed stable activity and selectivity in maleic anhydride hydrogenation for about 2000 hours. So the one-way catalyst lifetime of Cu/ZnO-C catalyst should be up to 2000 hours which is much longer than that of Cu/ZnO-Al2O3 used in industry.On Cu/ZnO-C catalyst deactivation factors are analyzed, the results show that the catalyst sintering and carbon deposition are the main reasons for catalyst deactivation.These studies demonstrated that the Cu/ZnO-C catalyst which we developed had the advantage of high activity and selectivity forγ-butyrolactone meanwhile stable catalytic performance. Our catalyst would be paid more atention to in nowadays of energy saving and emphasizing economic benefit.