From cyclohexanol to aniline: a novel dehydrogenation-amination-dehydrogenation strategy based on Pt-based catalyst

Anilines are essential building blocks and widely used in the synthesis of pharmaceuticals, agrochemicals, polymers and hetercycles, but its production is highly relied on traditional methods with petroleum-based chemicals as basis. Herein, a novel dehydrogenation-amination-dehydrogenation strategy is developed for the first time to the synthesis of aniline from cyclohexanol over various Pt-based catalysts. It is shown that Pt/CeO2 catalyst has the best performance. Comprehensive studies find that in the three catalytic steps, i. e., the dehydrogenation of cyclohexanol, the amination of cyclohexanone and the dehydrogenation of cyclohexylamine, the dehydrogenation of cyclohexylamine to aniline is the rate-determining step. Structure-performance relationship studies show that compared with Pt/C and Pt/Al2O3 catalysts, the excellent performance of Pt/CeO2 is originated from its suitable basic property and smaller Pt particle size, which are more favorable for the dehydrogenation steps. Meanwhile, 100h long-term stability is achieved and this strategy is also extended to other alcohol. This is a new strategy for the construction of aniline from simple alcohol and will provide a new and promising direction for the synthesis of aromatic amine with the features of cheapness, green and sustainability.