Catalytic conversions in green aqueous media: Highly efficient biphasic hydrogenation of benzene to cyclohexane catalyzed by Rh/TPPTS complexes

Exceptionally, high catalytic activities (TOF > 204,000 h−1) have been achieved in the hydrogenation of benzene to cyclohexane catalyzed by water-soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] in green aqueous/organic two-phase systems. The influence of several operating parameters on the biphasic benzene hydrogenation reaction was investigated. A great advantage of this reaction is that the highest catalytic activity was achieved at a low volume ratio of aqueous/benzene phase of 0.4. Rh/TPPTS catalytic complexes, which are stable toward sulfur-containing compounds, were easily recovered by a simple phase separation, and recycling experiments showed that the catalytic activity remained high in five consecutive runs.