Hydrolysis of Cellulose by Amorphous Carbon Bearing SO₃H, COOH, and OH Groups

TLDR

Solid catalysts are explored for environmentally benign saccharification of cellulose by hydrolyzing it into saccharides. The carbon catalyst’s effectiveness stems from its unique adsorption of β‑1,4 glucan, a property absent in conventional solid acids. Amorphous carbon bearing SO₃H, COOH, and OH groups hydrolyzes crystalline cellulose with an activation energy of 110 kJ mol⁻¹—lower than sulfuric acid—and can be recovered and reused without loss of activity.

Abstract

The hydrolysis of cellulose into saccharides using a range of solid catalysts is investigated for potential application in the environmentally benign saccharification of cellulose. Crystalline pure cellulose is not hydrolyzed by conventional strong solid Brønsted acid catalysts such as niobic acid, H-mordenite, Nafion and Amberlyst-15, whereas amorphous carbon bearing SO3H, COOH, and OH function as an efficient catalyst for the reaction. The apparent activation energy for the hydrolysis of cellulose into glucose using the carbon catalyst is estimated to be 110 kJ mol−1, smaller than that for sulfuric acid under optimal conditions (170 kJ mol−1). The carbon catalyst can be readily separated from the saccharide solution after reaction for reuse in the reaction without loss of activity. The catalytic performance of the carbon catalyst is attributed to the ability of the material to adsorb β-1,4 glucan, which does not adsorb to other solid acids.