Carbon-based strong solid acid for cornstarch hydrolysis

Abstract

Highly sulfonated carbonaceous spheres with diameter of 100–500nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180°C for 4h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91mg/mL could be obtained by hydrolyzing 20mg/mL cornstarch at 150°C for 6h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.