Evaluation of Ni/TiO2 catalysts in the semi-hydrogenation of alkynols under mild conditions in water

Abstract

The semi-hydrogenation of alkynols to alkenols is an important reaction for the synthesis of fine and bulk chemicals. This work reports titania-supported nickel catalysts, prepared by wet impregnation, that demonstrate efficacy for the semi-hydrogenation of 2-methyl-3-butyn-2-ol (MBY) into 2-methyl-3-butene-2-ol (MBE) under mild conditions (30–50 °C, 10 bar H₂) in water. The impacts of titania phases, calcination temperature, and metal loading were also investigated. The anatase titania catalyst calcined at 500 °C gave the best result with 98% conversion and 80% MBE at 30 °C after 6 hours. The superior yield stems from the titania phase, MBY adsorption, metal–support interactions, and the active species’ oxidation state, as evidenced using a range of characterisation and analytical techniques. These findings pave the way for the design of a stable, non-precious metal catalyst for the selective hydrogenation of alkynols under greener conditions, with the potential to supplant existing industrial methodologies.