Recent Advances in C5 and C6 Sugar Alcohol Synthesis by Hydrogenation of Monosaccharides and Cellulose Hydrolytic Hydrogenation over Non-Noble Metal Catalysts

Abstract

A new reality of the 21st century is the transition to a new type of economy and energy concepts characterized by the replacement of existing petrochemical routes to a bio-based circular economy. The needs for new strategies in obtaining basic products from bio-based resources with minimum CO2 traces has become mandatory. In this review, recent trends in the conversion of biomass-derived molecules, such as simple monomeric sugars and cellulose, to industrially important C5 and C6 sugar alcohols on heterogeneous catalysts based on non-noble metals are discussed focusing on the influence of catalyst structures and reaction conditions used on the substrate conversion and product selectivity. The challenges and prominent ideas are suggested for the further development of catalytic hydrogenation of naturally abundant carbohydrates to value-added chemicals on non-noble metal catalysts.

Chemocatalytic production of sorbitol from cellulose via sustainable chemistry – a tutorial review

“…Glucose is the monomer of cellulose and in solution, glucose molecules exist in an open-chain form or in cyclic forms that are subdivided into six-membered αor β-pyranose structures. 39 In aqueous solutions, glucose mostly exists in a stable ring conformation that has an energy barrier for the ringopening process of about 105 kJ mol −1 . 40 Glucose in the aldose conformation can be adsorbed onto metal surfaces via the oxygen lone pair η 1 O or via the carbonyl group η 2 CvO to complete a subsequent ring-opening hydrogenation reaction (Fig.…”

“…The functional support may provide acidity, alkalinity or redox properties, and it can provide a balance between hydrogenation and hydrogenolysis activity to control the selectivity of the desired product. 39,101 The catalyst should have a higher activation barrier than hexitol dehydrogenation and hydrogenolysis to facilitate the desorption of hexitol rather than conversion to by-products (Fig. 8).…”

Efficient Glucose Hydrogenation to Sorbitol by Graphene-like Carbon-Encapsulated Ru Catalyst Synthesized by Evaporation-Induced Self-Assembly and Chemical Activation

“…9 Although some nonprecious metal catalysts have also made breakthroughs in recent years, such as air-stable and reusable nano-Ni 2 P/HT 10 and Ni−Fe bimetallic catalysts, 11 their catalytic activities still fall short compared with those of precious metal catalysts. 9 Therefore, noble metals have been gathering increasing attention due to their high stability and excellent activity. Specifically, Ru has a relatively lower price compared to Pt and higher sorbitol selectivity, making it one of the most excellent active metals for the hydrogenation of glucose to sorbitol.…”

“…Nickel-based catalysts, such as Raney nickel, were first studied and used to hydrogenate glucose to sugar alcohol at the industrial level. However, they are prone to poisoning and sintering, and their instability cannot be ignored . Although some nonprecious metal catalysts have also made breakthroughs in recent years, such as air-stable and reusable nano-Ni 2 P/HT and Ni–Fe bimetallic catalysts, their catalytic activities still fall short compared with those of precious metal catalysts .…”

“…However, they are prone to poisoning and sintering, and their instability cannot be ignored. 9 Although some nonprecious metal catalysts have also made breakthroughs in recent years, such as air-stable and reusable nano-Ni 2 P/HT 10 and Ni−Fe bimetallic catalysts, 11 their catalytic activities still fall short compared with those of precious metal catalysts. 9 Therefore, noble metals have been gathering increasing attention due to their high stability and excellent activity.…”