Enhancing Tandem Partial Hydrogenation–Hydrolysis of Diphenyl Ethers to Cyclohexanols with Surface-Oxidized MXene

Abstract

Developing an efficient catalyst for upgrading diphenyl ethers to cyclohexanols is crucial for fine chemical synthesis, yet it possesses challenges owing to the complex tandem reaction network. Herein, a surface-oxidative Mo 2 TiC 2 MXene was fabricated, demonstrating partial hydrogenation−hydrolysis of diphenyl ether to cyclohexanol, achieving a 96.3% yield at a mild reaction temperature of 70 °C. Catalytic mechanism study reveals that the in situ hydrogen spillover from Mo−C sites to Mo−O−Ti sites generates the frustrated H + −H − pairs, which not only function as the unconventional hydrogenation sites for both diphenyl ether substrate and phenol intermediate but also act as the Brønsted sites for the hydrolysis of cyclohexenyl phenyl ether intermediate, thereby boosting the efficient production of cyclohexanol. Furthermore, they exhibited universality for synthesizing cyclohexanols from various diphenyl ethers and phenyl ethers. This study presents interesting bifunctional catalysis, offering a straightforward pathway to various cyclohexanols by harnessing surface-oxidized MXene catalysts to generate transient H + −H − pairs.