Abstract:

Nickel-based catalysts supported on ZrO₂, SiO₂, and Al₂O₃ supports, were prepared by incipient impregnation method and evaluated using liquid phase hydrogenation of maleic anhydride. BET,XRD,H₂-TPR and TPO-MS were employed to characterize these catalysts. Their catalytic performance varied with supports used. Among all the catalysts, Ni/Al₂O₃ catalyst exhibited the highest activity for C=C hydrogenation, while there was the lowest activity for C=O hydrogenation. Ni/ZrO₂ catalyst had the highest C=O hydrogenation activity, and maleic anhydride conversion and γ-butyrolactone selectivity were 100% and 79.2% respectively under the reaction condition of 483 K, 5 MPa of H₂ and 8 h of reaction time. The re-use experiment of catalyst demonstrated that the stability of catalyst in liquid phase hydrogenation of maleic anhydride was better for Ni/ZrO₂ and Ni/SiO₂ than Ni/Al₂O₃. Both selectivity and stability of catalysts could be explained by the interaction between succinic anhydride and catalyst.

Key words: hydrogenation, catalyst, catalyst support, nickel, zirconia, silica, alumina

摘要：

分别以ZrO₂、SiO₂与Al₂O₃为载体,采用等体积浸渍法制备了Ni质量分数为15%的催化剂,考察了其催化顺酐液相加氢性能,并利用BET、XRD、H₂-TPR以及TPO-MS等表征手段对催化剂进行了详细表征。结果表明,随载体不同各催化剂的加氢活性及选择性存在较大差异,Ni/Al₂O₃催化剂的C=C键加氢活性最高,但其几乎没有C=O加氢活性,催化顺酐加氢主产物为丁二酸酐。Ni/ZrO₂催化剂具有最高的C=O加氢活性,催化顺酐加氢主产物为γ-丁内酯,在反应温度为483 K,氢气压力为5 MPa的条件下反应8 h时,Ni/ZrO₂催化剂的γ-丁内酯选择性达79.20%。催化剂的套用实验表明,Ni/ZrO₂与Ni/SiO₂催化剂具有高的使用稳定性,Ni/Al₂O₃催化剂则在套用过程中快速失活。顺酐加氢至γ-丁内酯的中间产物——丁二酸酐与催化剂间的相互作用是影响催化剂加氢选择性及使用稳定性的主要原因。

关键词: 加氢, 催化剂, 催化剂载体, 镍, 二氧化锆, 二氧化硅, 氧化铝