Raney－Ni浸取方法对木糖加氢活性的影响

THE EFFECTS OF LEACHING PROCESS ON THE ACTIVITY OF RANEY-Ni IN XYLOSE HYDROGENATION

在木糖加氢反应中，考察了浸取（Ｌｅａｃｈｉｎｇ）方法对Ｒａｎｅｙ－Ｎｉ催化剂活性的影响。合金原料是１６０～２００目及＜３２０目的Ｎｉ－Ａｌ－Ｔｉ。实验表明，温度（５０～９３℃）及ＮａＯＨ浓度（２～６ｍｏｌ／Ｌ）越高，催化剂活性越好。但是，若先在低温和稀碱下浸取，再继以高温和浓碱的后处理，则比单一条件浸取时活性好。浸取起始１０～２０ｍｉｎ的反应剧烈程度，对合金破碎情况和催化剂活性均有显著影响；而后处理使活性提高的主要原因是对催化剂微孔的扩孔作用。

The effects of leaching conditions on the activity of Raney-Ni in xylose hydrogenation were studied. The original Ni-Al-Ti alloy used were particles of 160～200 and< 320 mesh.The activity was found to increase with leaching temperature(50～93℃)and concentration of NaOH(2～6mol/L). But the activity of mildly leached catalysts can be raised to the best by retreating them with higher temperature and alkali concentration. It is proved that the reaction intensity of the initial 10～20 min plays an important role on both the alloy disintegration and catalyst activity. The increase of activity by succeeding treatment mainly attributes to the enlarging of micropore inside catalyst pellets.