Catalytic Transfer Hydrogenolysis of Glycerol over Heterogeneous Catalysts: A Short Review on Mechanistic Studies

Abstract

Catalytic transfer hydrogenolysis, using liquid H‐donors in the absence of pressurized H2 under mild temperatures, is regarded as the most important technology to substitute traditional hydrogenation processes in industry. Despite decade development with several breakthroughs in catalyst design, the reaction mechanism involved in H2 generation and subsequent hydrogenolysis reactions is still under debate. In this review, transfer hydrogenolysis of glycerol, as a representative example, on metallic catalysts is revised critically with respect to surface reaction mechanism and catalyst design. The detailed reaction pathways for propanol, methanol, formic acid and ethanol for H2 generation have been discussed systematically. In particular, reaction mechanism for catalytic C−H cleavage, H spillover/transfer and C−O cleavage reaction steps will be critically revised with experimental and theoretical results in literature. Insights into reaction pathways, mechanism and H2 transfer efficiency and structure‐performance relation for Pd, Cu and Ni catalysts will be provided for future development of catalyst manufacture and process development. The outcome of this work is useful for successful implementation of bio‐refinery.

Liquid Organic Hydrogen Carriers (LOHCs) as H‐Source for Bio‐Derived Fuels and Additives Production

“…[74] However, glycerol can be further upgraded into different value-added products, such as biofuel, additives and chemicals. [75][76][77] Among these different transformations, particularly intriguing is the hydrogenolysis of glycerol to 1,2-propandiol (1,2-PDO), a fuel precursor of Otto Fuel II propellant. In this section, the use of different LOHCs as hydrogen source for 1,2-PDO synthesis is discussed.…”

Catalytic Biomass Upgrading Exploiting Liquid Organic Hydrogen Carriers (LOHCs)

“…Other catalytic systems for glycerol conversion into 1,2-PDO were developed by Cao et al using FA as the H source and by Pietropaolo et al, Zhou et al, and Zhang et al employing IPA as the hydrogen donor. Further transformations of glycerol via hydrogenolysis are treated in detail in a recent review focused on the use of various liquid H donors …”

“…Other catalytic systems for glycerol conversion into 1,2-PDO were developed by Cao et al 123 using FA as the H source and by Pietropaolo et al, 124 Zhou et al, 125 and Zhang et al 126 hydrogenolysis are treated in detail in a recent review focused on the use of various liquid H donors. 127 Table 3 summarizes representative results on FA-and IPAassisted productions of biofuels and biofuel additives.…”

Combined dehydrogenation of glycerol with catalytic transfer hydrogenation of H2 acceptors to chemicals: Opportunities and challenges

“…In general, as a chemical building block, the glycerol can be converted to a series of value-added chemicals, such as lactic acid (LA), propanediol (PDO), ethylene glycol (EG), glyceric acid, dihydroxyacetone, glycolic acid, and tartronic acid. ( Zhang et al, 2019 ; Meng et al, 2020 ; Liu et al, 2021 ; Sun et al, 2021 ; Yan et al, 2021 ; Zhang et al, 2021 ; Md Rahim et al, 2022 ). These products are widely used in food, medicine, organic synthesis, chemical industry, and other fields.…”