A novel approach to selecting thermomorphic multicomponent solvent systems (TMS) for hydroaminomethylation reactions

In industrial practice, several important examples of homogeneously catalyzed reactions using biphasic catalysis can be found. Using a transition metal catalyst soluble in another phase than the one containing the starting compounds and the products allow for simple separation and recycling of the usually expensive catalysts, but at the same time may cause severe problems with mass transfer. Thermomorphic multicomponent solvent (TMS) systems provide an elegant means to avoid this difficulty and take a big step toward the intensification of the process. One way to use these systems is the application of solvents that are not part of the reaction mixture. However, to reach higher space–time yields, it is also possible to integrate parts of the reaction mixture into the TMS system. The present work aimed to systematically analyze the available solvents for use in an integrated TMS system for the hydroaminomethylation of 1-octene with morpholine, and to develop criteria for the systematic search for applicable solvents in order to minimize catalyst leaching. Several solvents selected by rigorous application of these criteria were then tested in the reaction under biphasic and thermomorphic conditions.