Wang Kui,Ye Jun,Zhou Minghao,Liu Peng,Liang Xinyu,Xu Junming,Jiang Jianchun
Direct conversion of cellulose into levulinic acid and furfural in sulfolane media with the aid of water and H 2 SO 4 was performed at 140–220 °C under the pressures of 0–1.5 MPa. This approach could obtain 72.5 mol% levulinic acid and 11.5 mol% furfural formation under an optimal condition in which the mass ratio of sulfolane, water and H 2 SO 4 was 90:10:1. It was found that the decrease of water content led to an increasing yield of furfural and that the maximum furfural yield (51.1 mol%) could be obtained in the absence of water. The synergism of sulfolane and water in the selective liquefied system was demonstrated to be responsible for not only reinforced effect of optimizing and isolating the target products but also for reducing re-polymerization and side reactions. Furthermore, sulfolane in our case could be recycled and re-used for the conversion of cellulose with the same yield, which shed light on the remarkable potential for future industrial application.
Jinghua Wang,Jiangang Wang,Hongyou Cui,Zhihe Li,Ming Wang,Weiming Yi
Efficient esterification of biomass-derived levulinic acid (LA) to levulinate was investigated in molten salt hydrates (MSH) for the first time. A series of molten salt hydrates (LiBr·3H 2 O, LiCl·3H 2 O, ZnCl 2 ·3H 2 O, CaCl 2 ·3H 2 O and CaBr 2 ·3H 2 O) were examined in terms of their catalytic activity and Hammett acidity (H 0 ). Among them, CaBr 2 ·3H 2 O, ZnBr 2 ·3H 2 O and ZnCl 2 ·3H 2 O exhibited excellent activity. It was found that formic acid (FA), a compound that is cogenerated with LA in converting cellulose and hemicellulose as well as their derived sugars, can significantly enhance esterification of LA when reacting in MSHs. Mechanism analysis demonstrated that the promotion effect of FA on the formation of levulinate was resulted from transesterification of LA with butyl formate (BF). Under same conditions, as high as 99.8 % of butyl levulinate (BL) yield was obtained in CaCl 2 ·3H 2 O, while it was merely 19.6% in the absence of CaCl 2 ·3H 2 O. Hammett acidity measurement confirmed that CaCl 2 ·3H 2 O is able to promote the protonation of LA and FA, and thus accelerating the esterification and transesterification reactions. Besides, reacting in CaCl 2 ·3H 2 O can spontaneously form a biphasic reaction system: an organic phase that mainly consists of BL and n -butanol, and an aqueous phase composed of CaCl 2 , acids and water. Such a biphasic system help boost the esterification equilibrium and the subsequent separation and purification of the synthesized esters.
Catalytic biomass conversion is a crucial pathway for high-value utilization of renewable resources, yet current catalysts face limitations such as insufficient acid sites, poor product selectivity, and low cycling stability. This study developed a magnetic tin-based solid acid catalyst (Fe 3 O 4 @PDA-Sn) using 5-sulfoisophthalic acid sodium salt as a ligand and dopamine hydrochloride-coated Fe 3 O 4 for targeted catalytic conversion of sugarcane bagasse. Results demonstrated that the catalyst achieved a furfural yield of 86.2% and a levulinic acid yield of 32.5% at 170°C for 90 min, with FT-IR, NMR, and XRD confirming its differential deconstruction capability toward cellulose and hemicellulose. Mechanistic analysis demonstrated that the coordinated interaction between Brønsted and Lewis acid sites played a crucial role in steering the reaction toward specific pathways: hemicellulose hydrolysis products underwent dehydration to furfural (enriched in the organic phase), while cellulose was selectively cleaved to form levulinic acid. The catalyst maintained stable performance over 5 cycles without regeneration, with 97.3% magnetic recovery efficiency, offering a novel "facile magnetic separation–excellent cycling performance" strategy for hierarchical biomass conversion. This work provides critical insights into the design of multifunctional biorefinery catalysts for sustainable biomass valorization.
危险品化学品经营许可证（带存储）