Preparation of cyclohexanol from lignin-based phenolic concoction using controlled hydrogen delivery tool over in-situ Ru catalyst

This work investigated hydrodeoxygenation-hydrogenation of lignin-based methoxyphenols (obtained through hydrothermal liquefaction (HTL) of lignin) to cyclohexanol in high yields over in situ generated Ru(0)@Mg(OH) 2 catalyst in aqueous medium. The active catalyst Ru(0)@Mg(OH) 2 is generated in situ from hydrous ruthenium oxide (HRO)/Mg(OH) 2 under reaction conditions, as confirmed by various physiochemical techniques. Continuous and controlled addition of H 2 at constant temperature facilitated in improving the selectivity of cyclohexanol compared to the conventional batch mode (pre-set pressure) process. Complete conversion of methoxyphenols with 93–99% selectivity for cyclohexanol was achieved at 10 mL/min H 2 flow under comparatively milder reaction conditions. The adopted procedure and the in situ catalyst reported in this work is also effective for lignin-derived phenolic concoction. • Hydrodeoxygenation-hydrogenation of lignin-derived concoction over Ru(0)@Mg(OH) 2 . • In situ formation of Ru(0) is identified using various physicochemical techniques. • Reactions were carried out in an aqueous medium. • Cyclohexanol was achieved with 98% selectivity under continuous slow addition of H 2 . • Catalyst is recoverable and reusable with a minor decrease in the selectivity.