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.

Microporous carbon catalysts with large surface areas (800-1100 m(2) g(-1)) and high densities of SO3H groups (ca. 1.1 mmol g(-1)) were synthesized by sulfonation of zeolite-templated microporous carbon. The resulting SO3H-bearing microporous carbon catalysts exhibited higher catalytic performance for the hydrolysis of cellobiose and the Beckmann rearrangement than conventional solid acid catalysts and non-porous amorphous carbon with SO3H groups. The high catalytic activity of these reusable heterogeneous catalysts can be attributed to the high surface area and microporous structure, which enhance the efficient incorporation and diffusion of reactant molecules from solution to the SO3H groups on the catalysts.

SO3H‐bearing microporous amorphous carbon with a large BET surface area (≈2000 m2 g−1) and a high density of SO3H groups (0.5 mmol g−1) was investigated as a solid acid catalyst for the transesterification of triolein and esterification of oleic acid with methanol. The separable and reusable carbon catalyst exhibits higher catalytic performance for both reactions than conventional homogeneous and heterogeneous acid catalysts, including sulfuric acid, at 353 K. This carbon catalyst can provide methyl oleate yields over 99 %, even in a triolein–oleic acid mixture that resembles a crude vegetable oil, owing to efficient transesterification and esterification reactions. The carbon material is sufficiently hydrophobic to be distributed throughout the hydrophobic triolein phase, resulting in high catalytic performance for both reactions.