Recent progress on selective hydrogenation of phenol toward cyclohexanone or cyclohexanol

Phenol is considered as an important platform molecule for synthesizing value-added chemical intermediates and products. To date, various strategies for phenol transformation have been developed, and among them, selective hydrogenation of phenol toward cyclohexanone (K), cyclohexanol (A) or the mixture KA oil has been attracted great interest because they are both the key raw materials for the synthesis of nylon 6 and 66, as well as many other chemical products, including polyamides. However, until now it is still challengeable to realize the industrilized application of phenol hydrogenation toward KA oils. To better understand the selective hydrogenation of phenol and fabricate the enabled nanocatalysts, it is necessary to summarize the recent progress on selective hydrogenation of phenol with different catalysts. In this review, we first summarize the selective hydrogenation of phenol toward cyclohexanone or cyclohexanol by different nanocatalysts, and simultaneously discuss the relationship among the active components, type of supports and their performances. Then, the possible reaction mechanism of phenol hydrogenation with the typical metal nanocatalysts is summarized. Subsequently, the possible ways for scale-up hydrogenation of phenol are discussed. Finally, the potential challenges and future developments of metal nanocatalysts for the selective hydrogenation of phenol are proposed.

Automated summary

Phenol is an important platform molecule for synthesizing valuable chemical intermediates and products. The selective hydrogenation of phenol towards cyclohexanone or cyclohexanol has attracted great interest, but industrial application remains challenging. This review summarizes recent progress in selective hydrogenation of phenol with different catalysts, discussing the relationship between active components, support type, and catalyst performance, as well as the possible reaction mechanism and scale-up methods. Potential challenges and future developments of metal nanocatalysts for selective hydrogenation of phenol are also proposed.