The use of environment friendly biomass-based catalysts in bio refinery is highly desirable. In this paper, the preparation of sulfonated carbon materials from biopolymers (typically chitin and cellulose) facile one-step carbonization and sulfonation using p-toluenesulfonic acid as sulfonating agent was demonstrated. Unlike nitrogen-free cellulose, the basic nitrogen-containing sites generated from chitin decreased the acidity strength of the catalysts, which was confirmed by the results of P Nuclear Magnetic Resonance (P NMR). The suppressed acidity strength boosted the selectivity of 5-ethoxymethylfurfural (EMF) from 5-hydroxymethylfurfural (HMF) by inhibiting the formation of by-products, such as ethyl levulinate (EL) and humins. An 84.3 % yield of EMF from HMF was obtained over the as-prepared chitin-derived solid acid. The catalyst could be reused at least three times without obvious decrease of catalytic activity. Moreover, 74.6 %, 31.9 % and 60.7 % yields of EMF were obtained from fructose, sucrose and inulin in ethanol-containing solvents, respectively. This work offers an example for the synthesis of biofuels using biomass-derived catalysts.

中文翻译：

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甲壳素固体酸催化剂将 5-羟​​甲基糠醛和碳水化合物转化为 5-乙氧基甲基糠醛

在生物精炼中使用环境友好的生物质基催化剂是非常可取的。本文演示了以对甲苯磺酸为磺化剂，通过一步碳化和磺化从生物聚合物（通常是甲壳素和纤维素）制备磺化碳材料。与无氮纤维素不同，甲壳素产生的碱性含氮位点降低了催化剂的酸性强度，P核磁共振（P NMR）结果证实了这一点。酸性强度受到抑制，通过抑制乙酰丙酸乙酯 (EL) 和腐黑物等副产物的形成，提高了 5-羟甲基糠醛 (HMF) 中 5-乙氧基甲基糠醛 (EMF) 的选择性。通过所制备的几丁质衍生的固体酸，从 HMF 获得了 84.3% 的 EMF 产率。催化剂可重复使用至少3次，催化活性没有明显下降。此外，在含乙醇的溶剂中，从果糖、蔗糖和菊粉中分别获得了 74.6%、31.9% 和 60.7% 的 EMF 产率。这项工作为使用生物质衍生的催化剂合成生物燃料提供了一个例子。