Recyclable Zr/Hf-Containing Acid-Base Bifunctional Catalysts for Hydrogen Transfer Upgrading of Biofuranics: A Review

Abstract

The massive burning of a large amount of fossil energy has caused a lot of serious environmental issues (e.g., air pollution and climate change), urging people to efficiently explore and valorize sustainable alternatives. Biomass is being deemed as the only organic carbon-containing renewable resource for the production of net-zero carbon emission fuels and fine chemicals. Regarding this, the selective transformation of high-oxygen biomass feedstocks by catalytic transfer hydrogenation (CTH) is a very promising strategy to realize the carbon cycle. Among them, the important Meerwein-Ponndorf-Verley (MPV) reaction is believed to be capable of replacing the traditional hydrogenation strategy which generally requires high-pressure H2 and precious metals, aiming to upgrade biomass into downstream biochemical products and fuels. Employing bifunctional heterogeneous catalysts with both acidic and basic sites is needed to catalyze the MPV reaction, which is the key point for domino/cascade reaction in one pot that can eliminate the relevant complicated separation/purification step. Zirconium (Zr) and hafnium (Hf), belonging to transition metals, rich in reserves, can demonstrate similar catalytic efficiency for MPV reaction as that of precious metals. This review introduced the application of recyclable heterogeneous non-noble Zr/Hf-containing catalysts with acid-base bifunctionality for CTH reaction using the safe liquid hydrogen donor. The corresponding catalysts were classified into different types including Zr/Hf-containing metal oxides, supported materials, zeolites, metal-organic frameworks, metal-organic hybrids, and their respective pros and cons were compared and discussed comprehensively. Emphasis was placed on evaluating the bifunctionality of catalytic material and the key role of the active site corresponding to the structure of the catalyst in the MPV reaction. Finally, a concise summary and prospect were also provided centering on the development and suggestion of Zr/Hf-containing acid-base bifunctional catalysts for CTH.

Direct Ethyl Levulinate Production from Raw Lignocellulosic Biomass Mediated by a Novel Taurine-Based Imidazolium Ionic Liquid

“…One proposal to explain EL formation from hemicelluloses considers that furfuryl alcohol is produced via the Meerwein–Ponndorf–Verley (MPV) reduction reaction (Scheme ). , Since ethanol is the solvent, it could act as a H-donor for furfural reduction. Also, for this reaction to occur, the presence of a Lewis acid is necessary, usually a metal catalyst.…”

Micro/mesoporous LTL derived materials for catalytic transfer hydrogenation and acid reactions of bio-based levulinic acid and furanics

“…The reaction of AnL to GVL involves acid and reduction chemistry (e.g., hydration, CTH and lactonization) (Li et al, 2018;Antunes et al, 2022aAntunes et al, , 2022b. According to the literature, the reversible reaction between AnL and LA may occur via hydration-dehydration (Dutta and Bhat, 2021;Liu et al, 2021;Yuan et al, 2021), but AnL was not detected in the experiments using LA as substrate, whereas LA was formed using AnL as substrate. This is in agreement with literature studies for Hfcontaining catalysts in alcohol media (Al-Shaal et al, 2015;Li et al, 2018;Antunes et al, 2022bAntunes et al, , 2022a.…”

A Highly Effective Biomass-Derived Solid Acid Catalyst for Biodiesel Synthesis Through Esterification

“…In today’s society, due to the rapid development of industry, the accompanying sharp increase in the consumption of fossil fuels has led to a series of social problems including energy shortages and environmental pollution ( Li et al, 2017 ; Li et al, 2019 ; Zhao et al, 2019 ; Hu et al, 2021 ). Therefore, it is of great significance to develop the renewable bioenergy of huge potential in terms of green and efficiency, aiming to replace the increasingly scarce traditional fossil energy ( Liu et al, 2021 ; Li et al, 2022 ). Biodiesel, a kind of green and clean energy with low pollutant emission, non-toxic, good renewability and biodegradability, is regarded as a promising alternative to conventional fossil fuels ( Atadashi et al, 2013 ; Pan et al, 2019 ; Tan et al, 2021 ).…”