Abstract:

Based on the fact that reactant phenol is immiscible with water at room temperature, while it is soluble at the reaction temperature, and the products cyclohexanone and cyclohexanol are slightly soluble in water, water as the green solvent instead of volatile solvents of organic compounds is proposed and used for phenol catalytic hydrogenationFor this process, the reaction rate is not limited by the solubility of reactant into water, and the products can be easily separated from the solvent water by phase separation technique after reactionMeanwhile, the solvent water after reaction could be reused, which indicates that it is an environmental benign processFurthermore, it might be a potential approach to increasing the reaction rate of organic hydrogenation and improving the selectivity to desired products due to the different adsorptiondesorption properties of reactants and products on the surface of catalyst in various solventsFor example Raney Ni is of more powerful adsorption to H₂ in water than in organic solvent.

Key words: 温控型, 水－有机两相, 苯酚, 催化加氢

摘要：

根据反应物苯酚在室温下微溶于水，但是在反应温度下能与水互溶，而产物环己酮或环己醇微溶于水的特点，提出利用绿色溶剂水代替挥发性有机物，实现在水溶剂条件下的苯酚催化加氢反应。在反应过程中，反应速率不受传质限制，而且反应结束后可以通过简单的相分离技术实现产物与水的分离，分离得到的水可以循环使用，过程无废液排放，环境友好。更重要的是，由于催化剂在水相和在有机溶剂相中对反应物和产物具有不同的吸脱附性能，如Raney Ni催化剂在水相中比在醇类等有机溶剂相中具有更强的氢气吸附能力，这为提高催化加氢反应的活性和改变目标产物的选择性提供了一种有效的途径。

关键词: 温控型, 水－有机两相, 苯酚, 催化加氢