Structure Sensitivity of Reactions between Cyclopropane and Hydrogen on Supported Ruthenium Catalysts

Reaction (1) is called “hydrogenation,” reaction (2) “selective hydrocracking,” and reaction (3) “nonselective hydrocracking.” On Pd, It-, and Pt only reaction (1) is observed, while Co, Rh, and OS are active for reactions (1) and (2), and Fe, Ni, and Ru are able to catalyze all three reactions (I-5). The structure sensitivity of the three cyclopropane reactions on Ru catalysts has not yet been investigated in great detail. In previous work it was discovered that the nonselective hydrocracking reaction occurred only on catalysts containing relatively large Ru particles (I). On highly dispersed Ru catalysts, the nonselective hydrocracking reaction did not take place at all, and instead an increase in activity for reactions (1) and (2) with increasing Ru dispersion was noted (4). These findings indicated an apparent structure sensitivity of all three reactions of cyclopropane, and prompted us to investigate this phenomenon more closely. In the present study, the dispersion of Ru and the nature of the support are varied systematically in order to evaluate their relative contributions to the activity and selectivity in the three cyclopropane reactions.