Abstract

Direct production of the platform chemical 5-hydroxymethylfurfural (5-HMF) from cellulose is challenging due to the rigid structure of cellulose. Herein, 5-HMF was effectively obtained from cellulose with high loading concentrations (> 20 wt.%) via an Al₂(SO₄)₃-assisted mechanochemical method. The Al₂(SO₄)₃ not only acted as catalyst for its Lewis and Brønsted acidity, but also assisted the disruption of the hydrogen bonds among cellulose molecules during ball milling pretreatment. The particle size and crystallinity of the cellulose greatly decreased after Al₂(SO₄)₃-assisted ball milling pretreatment. The effects of various factors, including the organic solvent, reaction temperature and time, catalyst dose, and substrate concentration, on the yield of 5-HMF from cellulose were studied. A yield of 5-HMF up to 43.5% was obtained from cellulose via the developed mechanochemical-assisted method. A 36.1% yield of 5-HMF was retained when the initial cellulose loading concentration was as high as 21.6 wt.%. The green and efficient mechanochemical-assisted method was applicable to the efficient coproduction of 5-HMF and furfural from several waste biomass feedstocks.

Graphic abstract

摘要

由于纤维素的刚性结构，由纤维素直接生产平台化学物5-羟甲基糠醛（5-HMF）具有挑战性。在此，通过Al ₂（SO ₄）₃辅助的机械化学方法从具有高负载浓度（> 20 wt。％）的纤维素中有效地获得了5-HMF 。Al ₂（SO ₄）₃不仅充当其路易斯和布朗斯台德酸度的催化剂，而且还有助于在球磨预处理过程中破坏纤维素分子之间的氢键。Al ₂（SO ₄）₃后，纤维素的粒径和结晶度大大降低辅助球磨预处理。研究了有机溶剂，反应温度和时间，催化剂用量和底物浓度等各种因素对纤维素中5-HMF收率的影响。通过开发的机械化学辅助方法，从纤维素中获得的5-HMF产率高达43.5％。当初始纤维素装载浓度高达21.6重量％时，保留了36.1％的5-HMF产率。绿色高效的机械化学辅助方法适用于从几种废弃生物质原料中高效联产5-HMF和糠醛。

图形摘要