Heteropoly Acid-Based Catalysts for Hydrolytic Depolymerization of Cellulosic Biomass

Abstract

Cellulose is the most abundant source of biomass, which can be converted into monosaccharide or other chemical platform molecules for the sustainable production of chemicals and fuels. Acid catalysts can promote hydrolytic degradation of cellulose into valuable platform molecules, which is of great significance in the development of chemicals and biofuels. However, there are still some shortcomings and limitations of the catalysts for the hydrolytic degradation of cellulosic biomass. Heteropoly acid (HPA), as a green catalyst, seems to be more conducive to the degradation of cellulosic biomass due to its extreme acidity. HPAs can be designed in homogeneous and heterogeneous systems. Moreover, they can be easily separated from the products in both systems by a simple extraction process. According to the unique properties of HPAs (e.g., good solubility, high thermal stability, and strong acidity), using heteropoly acid-based catalysts to depolymerize and convert cellulose into value-added chemicals and biofuels has become one of the most remarkable processes in chemistry for sustainability. In this review, the characteristics, advantages, and applications of HPAs in different categories for cellulose degradation, especially hydrolysis hydrolytic degradation, are summarized. Moreover, the mechanisms of HPAs catalysts in the effective degradation of cellulosic biomass are discussed. This review provides more avenues for the development of renewed and robust HPAs for cellulose degradation in the future.

Selective Production of Glycolic Acid from Cellulose Promoted by Acidic/Redox Polyoxometalates via Oxidative Hydrolysis

“…Under aerobic conditions, FA is formed as the main product using H 5 PMo 10 V 2 O 40 (H 5 PMoV 2 ), H 6 PV 3 Mo 9 O 40 , K 5 V 3 W 3 O 19 , , or H 8 PV 5 Mo 7 O 40 . Especially, V-substituted POMs based on H 3 PMo 12 O 40 (H 3 PMo) have gained increasing attention in recent years and are widely applied in the valorization of lignocellulosic biomass. , Zhang et al tested different commercially available POMs in the Keggin structure, the most common structural form of the inorganic complexes, in the conversion of cellulose and found that Mo-containing POMs are especially promising for the selective conversion of cellulose to GA. For the best performing catalyst H 3 PMo, 91% conversion of cellulose was achieved with GA as the main product (yield = 49%) at 180 °C . FA was only formed as a side product with a yield of 10%.…”

Catalytic transfer hydrogenation of levulinic acid to gamma-valerolactone over a zirconium-based FDCA hybrid: insights into the effect of heteropoly acids

“…It is known that heteropoly acid (HPA) is a green and multifunctional catalyst with high catalytic activity and good stability, which can be used in homogeneous and heterogeneous reactions. [30][31][32] In recent years, many researchers loaded HPA on different supports to prepare heterogeneous catalysts rich in Brønsted acid (BA) sites. 33,34 Inspired by these studies, we modied our prepared Zr-FDCA hybrid by introducing phosphotungstic acid (HPWO) to obtain a multifunctional hybrid (Zr-FDCA-HPWO) with abundant LA and BA sites.…”

Sensitivity Analysis and Parameter Optimization for the Fractionative Catalytic Conversion of Lignocellulosic Biomass in the Polyoxometalate–Ionosolv Concept

“…12 Due to their structural diversity and tunable properties, POMs have attracted much attention for the valorization of biomass compounds during recent years. Beside the depolymerization and delignification of lignocellulosic biomass, 13,14 the preparation of several biobased products such as levulinic esters and lactic acid, has been investigated. 15−18 For the POM ionosolv approach, we found a correlation between carbohydrate solubilization and carboxylic acid yield, with more hemicellulose extraction resulting in higher formic acid (FA) yields.…”

“…Due to their structural diversity and tunable properties, POMs have attracted much attention for the valorization of biomass compounds during recent years. Beside the depolymerization and delignification of lignocellulosic biomass, , the preparation of several biobased products such as levulinic esters and lactic acid, has been investigated. − …”