Abstract

Zeolites (ZSM-5 and Beta) with different SiO₂/Al₂O₃ ratios were synthesized as solid acids for hydrolyzing cellulose in an inorganic ionic liquid system (lithium bromide trihydrate solution, LBTH) under mild conditions. The results indicated that the texture properties of zeolite had little effect on catalytic activity, while acidity of zeolite was crucial to the cellulose hydrolysis. In the LBTH system, H-form zeolites released H⁺ into the solution from their acid sites via ion-exchange with Li⁺, which hydrolyzed the cellulose already dissolved. This unique homogeneous hydrolysis mechanism was the primary reason for the excellent performance of the zeolites in catalyzing cellulose hydrolysis in the LBTH system. It was found cellulose could be completely hydrolyzed to glucose and oligoglucan by 2% (w/w on cellulose) zeolite at 140 °C within 3 h with a single-pass glucose yield 61%. The zeolites could be recovered with 50% initial catalytic activity after regeneration and reused with stable catalytic activity.

Graphic abstract

中文翻译：

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沸石催化的无机离子液体中纤维素的均相水解为葡萄糖

摘要

合成了具有不同SiO ₂ / Al ₂ O ₃比的沸石（ZSM-5和Beta）作为固体酸，用于在温和条件下在无机离子液体系统（三水合溴化锂溶液，LBTH）中水解纤维素。结果表明，沸石的织构性质对催化活性影响不大，而沸石的酸性对纤维素的水解至关重要。在LBTH系统中，H型沸石通过与Li ⁺进行离子交换将H ⁺从其酸位释放到溶液中。，它水解已经溶解的纤维素。这种独特的均相水解机理是沸石在LBTH体系中催化纤维素水解方面具有出色性能的主要原因。发现纤维素可以在140°C下在3 h内被2％（w / w在纤维素上为w / w）的沸石完全水解为葡萄糖和寡葡聚糖，单次通过葡萄糖产率为61％。沸石可以在再生后以50％的初始催化活性回收，并以稳定的催化活性再使用。

图形摘要