Atomistic modeling of catalytic molecules in a biphasic heptane/ionic liquid solutions in confinement

The microscopic behavior of Ru-based catalysts confined in nanometer sized pores in the supported ionic liquid phase (SILP) is studied using Molecular Dynamics. To this end, we have developed based on quantum mechanical calculations an atomistic force-field for the catalysts. Our system is made up of a silica pore with a functionalized inner surface including an ionic liquid (IL) and heptane in which both the catalysts and the substrates are initially placed. Our results reveal a phase separation of a nano-scale IL phase on the pore surface and a diffusive heptane phase on top of the IL phase. The catalysts are well dissolved into the IL phase within the pore and show much lower mobility than in the bulk IL. These linker free immobilization of the catalyst is expected to lead to a high selectivity. Our study aims to reveal the microscopic properties such as the configurational characteristics and dynamics of the catalysts in the pore, which are not accessible by experiments. We discuss the solvent effects, as well as the influence of the confined environment of the pore on the catalytic molecules and the relevance to novel experiments. This work is the first step towards an optimization and tuning of the setup of catalytic reactions within the framework of the SILP technology.