Raney镍催化松香加氢反应的机理

Mechanism of Hydrogenation Reaction of Rosin over Raney Nickel Catalyst

以 2 0 0号油为溶剂 ,Raney镍作催化剂研究了松香的加氢反应机理。由均匀设计实验方法得到松香加氢最优反应条件是 :温度 4 4 3K ,压力 5 0MPa ,催化剂用量占松香质量分数的 5 0 % ,溶剂质量分数为5 0 % ,反应时间 10 0min ,搅拌转速 6 0 0r/min ,据此确定了动力学的实验条件。在线跟踪测定了反应物浓度随反应时间变化的关系 ,使用EVIEWS软件进行参数拟合 ,经对Hougen Warson的 17种反应机理模型进行筛选 ,认为最可几的反应机理为 :催化剂表面上被吸附的氢原子和液相中的枞酸型树脂酸分子进行反应 ,氢的解离吸附为控制步骤 ,其反应速度与氢压成正比和产物浓度的平方成反比。并比较了松香催化加氢的熔融法和溶剂法 。

The mechanism of catalytic hydrogenation of rosin over Raney nickel catalyst has been studied using 200 # gasoline as a solvent. The optimal processing conditions for hydrogenation of rosin have been attained by the uniform design experiments as follows, temperature 443 K, pressure 5 0 MPa, catalyst content 5 0%(based on rosin), solvent content 50%(based on solution), reaction time 100 min, stirring rate 600 r/min , and the conditions for kinetics experiment were then obtained. The relation between reactant concentration and reaction time was traced on line, and the parameters have been regressed by using EVIEWS. Based on the experiment results, a suitable reaction model has been deduced from Hougen Warson 17 reaction mechanism models. It appeared that a reaction occurrs between abietic acid molecules and hydrogen atom adsorbed on the catalyst surface, and the dissociation adsorption of hydrogen could be the controlling step, and the reaction rate is proportional to the pressure of hydrogen and inversely proportional to the square of product concentration. Comparisons undertaken between melting method and solvent process showed that the hydrogenation reaction rate of the solvent process is greater than that of the melting method.