Effect of different additives on liquid phase selective hydrogenation performance of maleic anhydride over Ni/Al2O3
A series of nickel-based maleic anhydride hydrogenation catalysts were prepared by ultrasound-assisted precipi-tation method using P,Mg,Mo,and Cu additives,respectively.The catalysts were characterized and analyzed by N2 physical adsorption-desorption,X-ray diffraction(XRD),programmed temperature-raising reduction(H2-TPR),and ammonia-pro-grammed temperature-raising desorption(NH3-TPD),to investigate the effects of different additives on the crystalline struc-ture of the catalysts,the reduction performance,acid strength,BET specific surface area and pore structure.The results showed that the additives were highly dispersed in the catalyst system,while the introduction of the additives caused the specific surface area and pore volume of the catalysts to show different degrees of reduction.In addition,the additives in-creased the reduction temperature of the catalysts and enhanced the interaction force between the active metals and the car-riers,which led to the different degrees of reduction of the catalysts,and resulted in different numbers of Ni0 and Niδ+ with the characteristics of L-acid,which in turn affected the hydrogen activation and the adsorption capacity of the C=C/C=O bonds.The performance of the catalyst was evaluated using a fixed-bed maleic anhydride liquid-phase continuous hydroge-nation reaction,and it was found that the Ni-Mo/Al2O3 catalyst had the optimal γ-butyrolactone selectivity.Under the pro-cess conditions of reaction pressure of 5 MPa,reaction temperature of 150℃,molar ratio of 5∶1 for hydrogen anhydride,and space velocity of 1 h-1,the conversion rate of maleic anhydride was≥99.5%,the selectivity of γ-butyrolactone was≥54.34%.
NETL
NSTL
万方数据
