Studies On The Preparation Of Raney Ni Catalysts Modified With Fe And/or Mo And Their Hydrogenation Performance

Raney Ni was one of the most widely used catalysts in industry for the characteristic of low cost and easy to prepare, which still had the disadvantage of poor reactivty and selectivity, especially poor stability. It was an effective way to improve the performance of Raney Ni catalysts by adding other metals to modify Raney-Ni. In the present thesis, Raney Ni catalysts modified by Fe and/or Mo were prepared. Glucose hydrogenation was used as a probe reaction, meanwhile the loss of metals used to modify Raney Ni was investigated systematically. The main content as follows.(1) Reaction conditions of glucose hydrogenation were optimized as follows: glucose amount used 100g, water amount used 100 ml, pressure 5 MPa, temperature 140℃, catalyst amount used 4 g(wet weight).(2) Raney Ni modified by Fe showed higher activity than Raney Ni in the reaction with new catalysts. However, In the probe reaction with Raney Ni modified by Fe, the loss of Fe was numerous and the loss of Al was more serious than that in the reaction with Raney Ni, which led to the decrease of surface area and activity for Raney Ni modified by Fe. There was no loss of Mo in the probe reaction with Raney Ni modified by Mo, less loss of Al than in the probe reaction with Raney Ni, and the activity and stability of Raney Ni modified by Mo was fairly good in the probe reaction. The decrease of activity was mainly due to the loss of Al and the growth of particle size .(3) Raney-Ni catalysts modified by Fe and Mo together dissolved in the same conditions had the characteristic of smaller particle size and less loss of Al in the reaction process, which were attributed to higher activity and stablity of the catalysts.(4) Phase and valence of Fe and Mo in the alloy and modified Raney Ni catalysts was investigated. The loss of the metals used to modify the Raney Ni catalysts in the dissolving process of alloy and the probe reaction process were systematically investigated according to the phase and valence in the alloy and Raney Ni catalysts modified by Mo or Fe, respectively.