Solventless hydrogenation of benzene to cyclohexane over a heterogeneous Ru-Pt bimetallic catalyst

The hydrogenation of benzene to cyclohexane has attracted renewed attention in the chemical and petroleum industry, due to its application in the synthesis of many useful chemical intermediates. However, the development of highly efficient hydrogenation processes under mild solvent-free conditions is still a great challenge. Herein, we report a highly efficient Ru-Pt bimetallic catalyst, which was deposited on a zeolite-type MOF (MIL-101) by a simple colloidal deposition method, for neat benzene hydrogenation to cyclohexane. The catalyst system was shown to be able to provide excellent activities with a high selectivity for cyclohexane (in up to >99% yield). The enhanced reactivity is rationalized in terms of the synergy of Ru and Pt. The kinetics of neat benzene hydrogenation by the Ru-Pt/MIL-101 catalyst was investigated. The reaction showed a zero-order dependence on benzene while a first-order dependence on H2 pressure. A kinetic model of hydrogenation of neat benzene over the Ru-Pt catalyst was established based on the experimental results.