Progressing the<i>Crystal</i>Way to Sustainability: Strategy for Developing an Integrated Recycling Process of Homogeneous Catalysts by Selective Product Crystallization
Johanna Vondran, Astrid Ina Seifert, Kevin Schäfer, André Laudanski, Tabea Deysenroth, Kerstin Wohlgemuth, Thomas Seidensticker
Abstract
Catalyst recycling is the key toward the sustainable application of homogeneously catalyzed reactions whereby integrated processes with selective product crystallization allow high selectivity under mild conditions and subsequent purification of the product without the need for any auxiliary. In this work, we develop and implement a five-step strategy toward selective product crystallization as a tool for recycling of a homogeneous catalyst using the example model reaction of methoxycarbonylation of methyl-10-undecenoate using commercially available catalyst and ligand. The strategy includes targeted investigations on the reaction regarding the stability and productivity of the catalyst but also on the crystallization, regarding catalyst leaching, product purity, and recovery, to finally develop an integrated process. Implementation of this target-oriented approach allows for increasing catalyst productivity to a cumulated turnover number ∑TON 4600 after five recycling runs and obtaining a recovery of isolated product of 82% with 98% purity of the desired linear diester.