Fast and Selective Degradation of Biomass for Xylose, Glucose and Lignin under Mild Conditions

Abstract

The conversion of lignocellulose into valuable chemicals has been recognized as the key technology in green chemistry. However, selective degradation of hemicellulose and cellulose with the production of lignin is still a challenge. Therefore, a two-step process has been developed to degrade corncob into xylose and glucose under mild conditions. At first, the corncob was treated with the lower concentration of zinc chloride aqueous solution (30–55 w%) at 95 °C with a short reaction time (8–12 min) and 30.4 w% (selectivity = 89%) of xylose obtained with a solid residue of the composite of cellulose and lignin. Next, the solid residue was treated with a high concentration of zinc chloride aqueous solution (65–85 w%) at 95 °C for about 10 min, and 29.4 w% (selectivity = 92%) of glucose can be obtained. Combining the two steps, the total yield of xylose is 97%, while glucose is 95%. In addition, high pure lignin can be obtained simultaneously, which was confirmed using HSQC studies. Furthermore, for the solid residue of the first-step reaction, a ternary deep eutectic solvent (DES) (choline chloride/oxalic acid/1,4-butanediol, ChCl/OA/BD) has been used to separate the cellulose and lignin efficiently, and high-quality cellulose (Re-C) and lignin (Re-L) were obtained. Furthermore, it provides a simple method to disassemble the lignocellulose for monosaccharides, lignin, and cellulose.

Hydrodeoxygenation of Oxygenates Derived from Biomass Pyrolysis Using Titanium Dioxide-Supported Cobalt Catalysts

“…Due to environmental concerns and the need for sustainable development, as outlined in the Sustainable Development Goals announced by the United Nations in 2015, the current dependency on non-renewable fossil fuels, including petroleum-based feedstocks, should ideally be replaced by renewable resources [1][2][3]. Lignocellulosic biomasses (LCBs), which consist of cellulose, hemicellulose, and lignin, are promising renewable feedstocks for the production of biofuels and bio-based chemicals [4][5][6]. In the past decade, the technology of LCB valorization has focused on the production of bioethanol or value-added chemicals from the cellulose and hemicellulose fractions [7].…”