Recycling and Separation of Homogeneous Catalyst from Aqueous Multicomponent Mixture by Organic Solvent Nanofiltration.

J.-Kilian Schnoor,Jens Bettmer,Matthias Wessling,Marcel A Liauw,Johannes Kamp

doi:10.3390/membranes11060423

Abstract

Organic solvent nanofiltration (OSN) has evolved to an established recycling method for homogeneous catalysts. However, commercial availability has not circumvented the need for classification and the scoping of possible applications for specific solvent mixtures. Therefore, Evonik’s DuraMem® 300 was assessed for the recycling of magnesium triflate at two transmembrane pressures from a mixture of ethanol, ethyl acetate and water. Catalyst retention up to 98% and permeability of up to 4.44·10−1∙L∙bar−1∙m−2∙h−1 were possible when less than 25% ethyl acetate was in the mixture. The retention of some of the components in the ternary mixture was observed while others were enriched, making the membrane also suitable for fractioning thereof.

Highlights

The massive amounts of flue gases in the steel industry still go unused into waste cleanup
We evaluate the retention of each specific solvent in the mixture in dependency on the applied transmembrane pressure
Magnesium triflate was successfully recycled from an aqueous EtOAcEtOH-H2 O ternary mixture by applying organic solvent nanofiltration (OSN) to separate the homogeneous catalyst

Summary

Introduction

The massive amounts of flue gases in the steel industry still go unused into waste cleanup. While heterogeneous catalysis has been studied for a while, homogeneous catalysis is investigated. One of the main challenges is the poor separability of the catalyst from the reactants. Schnoor et al have looked at the idea to use organic solvent nanofiltration (OSN) for this separation [1]. During the investigation of the esterification of acetic acid with ethanol with homogeneous catalysts, to produce higher alcohols, different methods were tried for the recycling of the catalysts. Small-scale tests were carried out during which OSN showed good results and was chosen as a feasible option for a larger investigation. In the model system of ethanol, ethyl acetate and cyclohexane, the latter stood for an archetypal organic solvent, and the homogeneous catalyst was separated using

Methods

Results

Conclusion