Discovery Screening Workflow for New Polyolefin Catalysts

4 Chemical Reaction Engineering Aspects of Homogeneously Catalyzed Processes 

Liquid-phase homogeneous catalytic reactions which are carried out in the absence of a second or even third phase, i.e., a gas or an immiscible liquid, can be treated from a chemical reaction engineering point of view in analogy to other homogenous reactions. If the chemical kinetics of such homogeneous catalytic reactions are known, the reactor performance can easily be predicted with respect to conversion and selectivity. The required procedures have been extensively described in various textbooks, e. g., [1-3]. 

In two-phase systems in which the catalytic reaction takes place in the liquid phase between a liquid reactant and gaseous reactants, the latter have to be transferred over the gas/liquid boundary layer into the liquid phase. In this situation the reaction engineering prediction described above can be performed in an analogous way as long as the rate of transfer of the gaseous reactants into the liquid phase is fast compared with the intrinsic catalytic reaction. Under these circumstances it can usually be assumed that the liquid-phase concentrations of the gaseous reactants correspond to gas/liquid thermodynamic equilibrium. 

The situation may become even more complicated if a second liquid phase is present it may either serve as the reaction space containing the catalyst while the product as well as a part of the reactants exist in the first liquid phase, or it may act as a solvent into which a desired intermediate is extracted from the reacting liquid phase (cf. Section 3.1.1.1). To describe quantitatively the course of a homogeneous catalytic reaction in a multiphase chemical reactor it is necessary to combine the following information in a suitable reactor model  

It is the intention of this contribution to give an overview of the procedures to be applied to model a multiphase reactor and its performance for a homogeneous catalytic reaction for a detailed multiphase design the reader is referred to appropriate textbooks. 

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Figure 6. Discovery screening workflow for new polyolefin catalysts.

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