低碳混合醇合成中的耦合效应

根据CO加氢合成低碳混合醇催化反应的特点,从耦合效应角度,对影响产物选择性的因素进行了分析和计算.由于产物分布在动力学上受Schulz-Flory方程的制约,不同碳数的醇达最大选择性时要求不同链增长几率a相匹配.推导并计算出混合醇合成体系混合自由能及反应自由能计算公式,得到了△G°=0时转变温度与链增长几率a之间的关系.由于产物分布和混合效应的影响,混合醇比单醇的合成热力学更为有利,转变温度相应提高.通过改变催化剂组成调节a值并选择合适的反应温度是提高混合醇合成选择性的可能途径.

The coupling effects in lower mixed alcohols synthesis

Based upon the characteristics of lower mixed alcohols synthesis from CO and hydrogen, the parameters affecting alcohol selectivity were analyzed and calculated in the viewpoint of coupling effects. Owing to the product distribution is restricted kinetically by Schulz-Flory equation, the optimum selectivities for alcohols with different carbon numbers require matching with different chaingrowth probability a*. The calculation equations for mixed free energy and reaction free energy in the mixed alcohols synthesis system were calculated and deduced, obtaining the relation between conversion temperature and chaingrowth probability at △G°=0. The synthesis thermo-dynamic of mixed alcohols is more beneficial than that of single alcohol due to the effects of product distribution and mixed effects. And conversion temperature rises correspondly. It is a possible way to promote the selectivity of mixed alcohol synthesis when changing catalyst composition, regulating a value and choose suitable reaction temperatures.