Selective Hydrogenation Processes by Means of a Catalyst Preparation Method Using Volatile Metal Complexes

以Co/Al_（120）_3为前驱体，制备了具有高选择性的巴豆醛部分加氢催化剂，Zr（dpm）_2复合物的加入提高了催化剂的催化活性和选择性。其他Zr-配合物，挥发性小于Zr（dpm）2，建议劣化效果，和前体的挥发性是关键因素。研究了Zr（dpm）2分解后Zr的状态。前驱体在Co存在下在氢气流中分解，并沉积由ZrO 2作为主要成分组成的薄膜。但XPS也发现了低价态Zr（Zr^0），这种低价态Zr似乎导致了高选择性。这种低价Zr的形成对于我们的制备方法是独特的。对反应条件进行了优化，巴豆醇的最高收率可达80%以上。该催化剂比文献中报道的任何其他催化剂都更有活性。在Co中添加Zr促进了C=O加氢反应，抑制了C=C加氢反应，该催化剂制备方法有效地引入了特定价态的助催化剂，对开发新的催化剂体系具有重要意义。

Preparation of Co-based bimetallic catalysts has been tried using volatile metal complexes as precursors, and a highly selective catalyst in partial hydrogenation of crotonaldehyde has been found. Addition of Zr (dpm) 2 complex in Co/A1203 improved both activity and selectivity of the catalyst in hydrogenation of crotonaldehyde to form crotylalcohol. Other Zr-complexes, less volatile than Zr (dpm) 2, suggested inferior effect, and the volatility of the precursor is the critical factor. The state of Zr after decomposition of Zr (dpm) 2 was studied. The precursor decomposed in hydrogen flow in the presence of Co and deposited a thin film consisting of ZrO2 as the main component. However low valent Zr (Zr^0) was also found by XPS,and such low valent Zr seemed to result in the high selectivity. Formation of such low valent Zr was unique for our preparation method. The optimization of the reaction condition was tired and finally highest yield of crotylalcohol was found to be more than 80%. This catalyst is more active than any other catalyst reported in the literature. Addition of Zr in Co accelerated the C=O hydrogenation, and suppressed the C=C hydrogenation.Our new method of catalyst preparation was effective in introducing catalyst promoter in special valence state, and useful in the development of new catalyst systems.