Systematic Approach to Solvent Selection for Biphasic Systems with a Combination of COSMO‐RS and a Dynamic Modeling Tool

Abstract

Biphasic aqueous‐organic systems are important reaction systems for catalytic processes. This is especially true for biocatalysis where the range of accessible products can be significantly extended. In such systems, the aqueous phase is the reactive phase in which the biocatalyst is dissolved and the organic phase is nonreactive and acts as substrate reservoir and as in situ product extraction solvent. Here, the choice of the nonreactive phase is highly important for the overall performance of the system. In this contribution, a systematic approach to solvent selection for biphasic aqueous‐organic systems is presented with respect to partition coefficients. The model reaction is the stereoselective carbon‐carbon coupling of two 3,5‐dimethoxy‐benzaldehyde molecules to (R)‐3,3',5,5'‐tetramethoxy‐benzoin catalyzed by benzaldehyde lyase (EC 4.1.2.38) from Pseudomonas fluorescens. A systematic approach to solvent selection consisting of two steps is proposed: Firstly, the conductor‐like screening model for real solvents (COSMO‐RS) is used to facilitate a fast solvent screening. Since this is an ab initio approach it allows a pre‐screening without laborious experimental input. The proposed ranking of solvents, based on the ratio of partition coefficients at infinite dilution, is a sound basis for the successive steps. Secondly, a dynamic model is fitted to experimental data in order to obtain detailed and reliable results for mass transfer and partition coefficients. Therefore, the method makes efficient use of the experimental data and substantiates quantitative results with guided experiments.

An overview of the biphasic dehydration of sugars to 5-hydroxymethylfurfural and furfural: a rational selection of solvents using COSMO-RS and selection guides

“…143 Similarly to the case of the biphasic dehydration of sugars with in situ extraction of furans subject of this review, COSMO-RS has also previously been used for the screening of solvents in aqueous biphasic system in the enzymatic production of (R)-3,3′,5,5′-tetramethoxybenzoin. 144 Another case is the estimation of the partition ratio of Biphephos ligand in different pairs of solvents for the selection of thermomorphic solvent systems in which to recycle molecular catalysts in the hydroformylation of olefins. 145 In addition to these LL-based systems with molecular solvents, this method has also proven successful in predictions in alternative media, like the solubility of gases like CO 2 in ILs 146 or the extraction of linalool from terpenes in ChCl-based DESs.…”

Saccharomyces cerevisiae: a potential stereospecific reduction tool for biotransformation of mono‐ and sesquiterpenoids

“…Biphasic aqueous‐organic systems are pertinent in bioprocesses as this system can be effectively approached for a wide selection of products. Herein, the choice of organic solvents is the decisive factor that affects the overall performance of the system88. The reductive biotransformation of geraniol to citronellol in organic solvents utilizing various yeasts (baker's yeast, XST‐KO yeast, LP yeast, alcohol yeast, dry yeast, Angel yeast and Meishan yeast) was also studied, with the results displaying the superiority of N ‐hexane over the use of butyl acetate in the conversion process119.…”

Conceptual Design of Azeotropic Distillation Processes

“…While CAMD constitutes a vital possibility to innovative entrainer selection, the limited accuracy of the property prediction models limits the power of CAMD and necessitates experimental validation. Although the absolute accuracy of the predictions might be low, the qualitative ranking of solvent candidates has been confirmed experimentally at least in some reported case studies [15,19].…”