Highly selective hydrogenation of guaiacol to cyclohexanol over carbon-encapsulated highly dispersed cobalt catalyst

Cyclohexanol is an important chemical intermediate. In recent years, guaiacol has received widespread attention as a lignin model compound for hydrodeoxygenation (HDO) to prepare cyclohexanol. However, it remains a major challenge to prepare a highly active and stable catalyst. In this work, a series of carbon-encapsulated Co-based catalysts with different Co/C ratios were synthesized using an extremely simple approach for the HDO of guaiacol to cyclohexanol. Among them, the Co1@C1 catalyst (with a ratio of 1:1 between glucose and cobalt nitrate) showed the best catalytic activity, achieving almost complete directional conversion of guaiacol to cyclohexanol within 60 min at 200 °C, with a yield of up to 98.5 % for cyclohexanol. In addition, the catalyst also exhibited extremely high stability, and no significant deactivation was observed after 5 cycles under optimal conditions. The research outcomes point out that highly dispersed CoO NPs are the main active centers. The graphite layer ensures the stability of the Cox@Cy catalyst, and effectively avoids the leaching of metals in high-temperature reactions. This work provides important reference for the development of high activity, high stability, and low-cost catalysts for the hydrogenation of phenolic derivatives in the future.