Activity Coefficients for Liquid Organic Reactions: Towards a Better Understanding of True Kinetics with the Synthesis of Jasmin Aldehyde as Showcase.

Philippe M. Heynderickx

doi:10.3390/ijms20153819

Abstract

The aldol condensation of benzaldehyde and heptanal is taken as an example of reversible liquid phase organic reactions to show that inclusion of activity coefficients reveal distinct differences in conversion and product distribution when different solvents methanol, ethanol, n-propanol, or n-butanol are used. The purpose of this work is to show a pronounced solvent effect for a given set of identical kinetic parameters, i.e., the same liquid phase kinetics can result in different conversion and yield values, depending on the choice of solvent. It was shown that subsequent parameter estimation without inclusion of the activity coefficients resulted in a pronounced deviation from the ‘true’ kinetics, up to a factor of 30. It is proposed that the usage of average activity coefficients gives already a significant improvement, resulting in acceptable parameter estimates.

Highlights

Carbon–carbon bond formation reactions are paramount cornerstones in organic synthesis
In order to scale up laboratory work, experimental concentration data can be used for parameter estimation in the absence of diffusion or gradients and these parameters can be used as input for simulation codes, which can investigate the optimal conditions for industrial practice
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Summary

Introduction

Carbon–carbon bond formation reactions are paramount cornerstones in organic synthesis. In order to scale up laboratory work, experimental concentration data can be used for parameter estimation in the absence of diffusion or gradients and these parameters can be used as input for simulation codes, which can investigate the optimal conditions for industrial practice. These kinetic parameters are of paramount importance for the description of the process. In this respect, it was noticed by the author that not many papers deal with the inclusion of the so-called ‘activity’ or ‘activity coefficients’ of the compounds. Examples of applications of activity coefficients in parameter estimation can be found in references [3,4,5,6,7,8,9]

Objectives

Methods

Results

Conclusion