Acid–Base Bifunctional Hf Nanohybrids Enable High Selectivity in the Catalytic Conversion of Ethyl Levulinate to γ-Valerolactone

Abstract

Abstract:The catalytic upgrading of bio-based platform molecules is a promising approach for biomass valorization. However, most solid catalysts are not thermally or chemically stable, and are difficult to prepare. In this study, a stable organic phosphonate-hafnium solid catalyst (PPOA-Hf) was synthesized, and acid-base bifunctional sites were found to play a cooperative role in the cascade transfer hydrogenation and cyclization of ethyl levulinate (EL) to γ-valerolactone (GVL). Under relatively mild reaction conditions of 160 • C for 6 h, EL was completely converted to GVL with a good yield of 85%. The apparent activation energy was calculated to be 53 kJ/mol, which was lower than other solid catalysts for the same reaction. In addition, the PPOA-Hf solid catalyst did not significantly decrease its activity after five recycles, and no evident leaching of Hf was observed, indicating its high stability and potential practical application.

Cascade Upgrading of Biomass-Derived Furfural to γ-Valerolactone Over Zr/Hf-Based Catalysts

“…Therefore, it is necessary to fully consider both the structure and acid-base properties of the catalyst to improve the catalyst activity. Since Zr/Hf-based catalysts show excellent catalytic performance in CTH reactions and are more economical than precious metals, more and more researchers applied them to the reaction of converting GVL from FF ( Li et al, 2016 ; Wu et al, 2018 ; Zhou et al, 2019a ; Wang et al, 2019 ).…”

One-step upgrading of bio-based furfural to γ-valerolactone via HfCl4-mediated bifunctional catalysis

“…There is thus an urgent need to seek renewable energy substitutes. 1,2 Biomass is the most abundant organic carbon source and is widely distributed, which make it oen used to produce biofuels and various valuable chemicals. [3][4][5][6] Among the biomass feedstocks, C5 sugars (e.g., arabinose and xylose) obtained from hemicellulose can be converted into furfural (FF), furfuryl alcohol (FA), and levulinic acid, which can be further upgraded to g-valerolactone (GVL), an important and valuable chemical.…”

Catalytic Stereoselective Conversion of Biomass-Derived 4′-Methoxypropiophenone to Trans-Anethole with a Bifunctional and Recyclable Hf-Based Polymeric Nanocatalyst

“…By then, renewable energy is expected to provide one-third of the world's electricity, and its total capacity will be twice the current total power capacity in China. Therefore, as an important raw material for renewable and sustainable development, the irreplaceable role of biomass resources in the production of energy, materials, and chemical products has attracted widespread attention [8][9][10]. Compared with petroleum-based chemicals, the distinguishing characteristics of bio-based chemicals are their considerable water and troleum-based chemicals, the distinguishing characteristics of bio-based chemicals are their considerable water and oxygen content, thermal instability, and corrosiveness during the conversion process, which hinders the application and development of biomass resources [11].…”