Predictive Modelling of Phase-Transfer Catalyst Systems for Improved and Innovative Design

Phase-transfer catalyst (PTC) systems contain two immiscible liquid phases with a heterogeneous PTC transferring active ion from one phase to the other for converting the reactant to the desired product, and in the process generating the inactive ion. This type of reacting systems is receiving increasing attention as a novel organic synthesis option due to its flexible and easier operation, higher production yield, and ability to eliminate expensive solvents, although, not eliminating the use of solvents.

New mathematical models of the PTC system, which includes physical and chemical equilibrium, reaction mechanism and unit operation has been developed. In the developed model, the PTC system is divided into four sub-systems of aqueous-organic solvent partition, inorganic salt in aqueous phase, PTC in aqueous phase, and PTC in aqueous phase. Each subsystem requires an appropriate thermodynamic model to predict the partition and equilibrium of the involved species. A new predictive electrolyte model (e-KT-UNIFAC) that has the capability to predict the partition and equilibrium of systems containing novel PTCs has been embedded into the reactor model. With this option, the application range has been significantly widened, making it feasible to identify new and innovative biphasic reaction options.

In this paper, the predictive qualities of the new model together with the improvements in the predicted design and operation of reaction with PTC systems are highlighted. Also, applications of problem-specific models for selecting improved design alternatives based on different design targets are presented.