Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, 226-8503, Japan.
ChemSusChem. 2011 Jun 20;4(6):778-84. doi: 10.1002/cssc.201000431. Epub 2011 May 18.
The correlation between catalytic performance and structure of a cellulose-derived and carbon-based solid acid (CCSA), an amorphous carbon bearing SO(3)H, COOH, and phenolic OH groups, was investigated. Sulfonation of partially carbonized cellulose under a N(2) atmosphere resulted in the formation of a CCSA, which was amorphous carbon consisting of small polycyclic aromatic carbon sheets with a high density of SO(3)H groups (ca. 2 mmol g(-1)). CCSAs were prepared from carbon precursors, which were obtained at temperatures ≤723 K, and exhibited a high catalytic performance for the esterification of acetic acid with ethanol and for the hydrolysis of cellobiose, although the surface areas were small (<5 m(2) g(-1)). In contrast, CCSAs, which were prepared from carbon precursors obtained at ≥823 K, exhibited much lower catalytic activities for both reactions, although the CCSAs had sufficient amounts of SO(3)H groups. Structural analyses, including spectroscopic analysis of CCSAs with adsorbed probe molecules, revealed that cross-linking between the polycyclic aromatic carbon sheets caused the sharp decrease in activity.
研究了纤维素衍生的和基于碳的固体酸（CCSA）的催化性能与结构之间的关系，CCSA 是一种含有 SO(3)H、COOH 和酚 OH 基团的无定形碳。在 N(2)气氛下部分碳化纤维素的磺化反应生成了 CCSA，它是由具有高密度 SO(3)H 基团（约 2 mmol g(-1)）的小多环芳烃碳片组成的无定形碳。CCSA 是由在 ≤723 K 温度下获得的碳前体制备的，尽管比表面积较小（<5 m(2) g(-1)），但对乙酸与乙醇的酯化反应和纤维二糖的水解反应具有很高的催化性能。相比之下，由在 ≥823 K 温度下获得的碳前体制备的 CCSA 对这两种反应的催化活性要低得多，尽管 CCSA 具有足够数量的 SO(3)H 基团。结构分析，包括吸附探针分子的 CCSA 的光谱分析，表明多环芳烃碳片之间的交联导致活性急剧下降。
