Secondary Effectiveness Factors and Solubility Effects for Catalytic Reactions in Series,ACS Catalysis

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Secondary Effectiveness Factors and Solubility Effects for Catalytic Reactions in Series
ACS Catalysis ( IF 11.3 ) Pub Date : 2020-03-23 , DOI: 10.1021/acscatal.0c00185
Baron Peters _{1,

2}

Affiliation

Thiele moduli and effectiveness factors are powerful ways to account for mass transfer limitations on reactions occurring within porous catalyst particles. Effectiveness factors have been developed for numerous rate laws, geometries, and nonisothermal situations, but not for reactions in series. This manuscript develops an effectiveness factor for the second step in the A → B → C reaction sequence with first-order kinetics and slab geometry. The expressions are more complicated than the familiar primary effectiveness factors because the intermediate B is being generated and consumed within the catalyst particle. We illustrate the application of the secondary effectiveness factor by modeling the conversion from A to B and C for plug flow through a porous ceramic monolith catalyst. Then we modeled A → B → C in a slurry of catalyst flakes within a well-stirred batch reactor, including equilibrium solvent-molecular sieve partition coefficients for the A and B species. When both Thiele moduli are small and the molecular sieve adsorbs A more strongly than B, the second reaction is suppressed. This situation can give essentially 100% yield of B, even when A and B have similar reactivities within the catalyst. Our results provide a framework for predicting the effects of interior mass transfer limitations and solvent–solid phase partitioning in heterogeneously catalyzed series reactions.

中文翻译：

系列催化反应的次要影响因素和溶解度影响

蒂尔模量和有效性因子是解决多孔催化剂颗粒内发生的反应的传质限制的有效方法。已经为许多速率定律，几何形状和非等温情况开发了效率因子，但没有针对串联反应进行开发。该手稿为具有一级动力学和平板几何形状的A→B→C反应序列中的第二步开发了效率因子。由于中间体B在催化剂颗粒中生成和消耗，因此表达式比熟悉的主要有效性因素更复杂。我们通过模拟从转换示出了次要有效性因子的应用阿到乙和C用于塞流通过多孔陶瓷整体催化剂。然后，我们在搅拌良好的间歇式反应器中的催化剂薄片浆液中对A→B→C进行建模，包括A和B物种的平衡溶剂-分子筛分配系数。当两个蒂尔模量均较小且分子筛比B吸附A时，第二反应被抑制。即使A和B发生这种情况，B的产量也可以达到100％在催化剂内具有相似的反应性。我们的结果为预测内部传质限制和非均相催化系列反应中溶剂-固相分配的影响提供了框架。

更新日期：2020-03-24

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