Hydrogen Generation from Organic Hydrides under Continuous-Flow Conditions Using Polymethylphenylsilane-Aluminum Immobilized Platinum Catalyst.

Hydrogen is an important resource for realizing the goal of a hydrogen-based society as well as for synthetic organic chemistry. Catalytic dehydrogenation of organic hydrides such as methyl cyclohexane is attractive for hydrogen storage and transportation in terms of reversibility and selectivity of catalytic reactions and hydrogen storage density. We developed a highly active polymethylphenylsilane-aluminum immobilized platinum catalyst (Pt/MPPSi-Al 2 O 3 ) for dehydrogenation of organic hydrides. Organic hydrides were fully converted into the corresponding aromatic compounds under reactive distillation conditions at 200 °C or under circulation-flow conditions using the Pt/MPPSi-Al 2 O 3 catalyst packed in a column at 260 °C. The dehydrogenation reaction reached a maximum conversion at equilibrium (ca. 60%) under continuous-flow conditions at 260 °C. This catalytic continuous-flow dehydrogenation was applied to a formal hydrogen transfer from organic hydrides to unsaturated organic substrates under sequential and continuous-flow conditions for practical flow hydrogenation reactions by connecting two different heterogeneous catalysts packed in columns.