Exploring Hydrogen Sources in Catalytic Transfer Hydrogenation: A Review of Unsaturated Compound Reduction

Abstract

Catalytic transfer hydrogenation has emerged as a pivotal chemical process with transformative potential in various industries. This review highlights the significance of catalytic transfer hydrogenation, a reaction that facilitates the transfer of hydrogen from one molecule to another, using a distinct molecule as the hydrogen source in the presence of a catalyst. Unlike conventional direct hydrogenation, catalytic transfer hydrogenation offers numerous advantages, such as enhanced safety, cost-effective hydrogen donors, byproduct recyclability, catalyst accessibility, and the potential for catalytic asymmetric transfer hydrogenation, particularly with chiral ligands. Moreover, the diverse range of hydrogen donor molecules utilized in this reaction have been explored, shedding light on their unique properties and their impact on catalytic systems and the mechanism elucidation of some reactions. Alcohols such as methanol and isopropanol are prominent hydrogen donors, demonstrating remarkable efficacy in various reductions. Formic acid offers irreversible hydrogenation, preventing the occurrence of reverse reactions, and is extensively utilized in chiral compound synthesis. Unconventional donors such as 1,4-cyclohexadiene and glycerol have shown a good efficiency in reducing unsaturated compounds, with glycerol additionally serving as a green solvent in some transformations. The compatibility of these donors with various catalysts, substrates, and reaction conditions were all discussed. Furthermore, this paper outlines future trends which include the utilization of biomass-derived hydrogen donors, the exploration of hydrogen storage materials such as metal-organic frameworks (MOFs), catalyst development for enhanced activity and recyclability, and the utilization of eco-friendly solvents such as glycerol and ionic liquids. Innovative heating methods, diverse base materials, and continued research into catalyst-hydrogen donor interactions are aimed to shape the future of catalytic transfer hydrogenation, enhancing its selectivity and efficiency across various industries and applications.

Synthesis, characterisation, and catalytic application of a soluble molecular carrier of sodium hydride activated by a substituted 4-(dimethylamino)pyridine

“…4 ). Previous studies 41 – 43 have established that 1,4-cyclohexadiene (CHD) is a convenient, easily handled liquid transfer hydrogenation reagent so it was employed as the hydrogen source. Alkali-metal-mediated reactions are often solvent dependent with some of the most distinct behaviours found between low-polarity arene and polar ether solvents, therefore C 6 D 6 and d 8 -THF respectively were investigated as the medium in this study with the temperature fixed at 70 °C and catalyst loading at 10 mol%.…”

Game-Theory-Based Design and Analysis of a Peer-to-Peer Energy Exchange System between Multi-Solar-Hydrogen-Battery Storage Electric Vehicle Charging Stations

“…Hydrogen storage tanks [39], as devices for storing hydrogen, come in different types based on various hydrogen storage technologies. The technology currently used most is high-pressure gaseous hydrogen storage.…”

Nickel-catalyzed tandem conversion of paraformaldehyde : methanol to hydrogen and formate/chemo- and stereoselective hydrogenation of alkynes under neutral conditions

“…1). 27,38–46 Recently, increasing interest has been in utilizing earth-abundant metal-based catalysts and sustainable feedstock for (de)hydrogenation reactions. 47,48 Among the 3d transition metal-based catalysts, nickel has received significant attention due to its demanding structures as well as remarkable reactivity with maximum alterability, resulting in numerous fascinating applications in both academic and applied research.…”