Environmentally benign production of chemicals and energy using a carbon-based strong solid acid

This paper reviews amorphous carbon bearing sulfonic acid groups as an efficient solid acid catalyst for the production of various chemicals. The material is produced by the sulfonation of incompletely carbonized organic carbon to yield an insoluble, stable, and inexpensive catalyst with acid catalytic activity comparable to that of sulfuric acid (H2SO4). The carbon material can also be readily separated from liquid products by decantation or filtration, and can be repeatedly reused without any decrease in activity. As a replacement for H2SO4 in industrial chemical production, a carbon-based solid acid catalyst thus has the potential to substantially reduce energy consumption and waste generation. The carbon catalyst also converts crude vegetable oils into biodiesel in a one-step process, demonstrating the potential utility of this material in a wide range of catalytic processes. The remarkable catalytic activity of this material is attributable to the incorporation of reactants into the bulk structure and the high density of strongly acidic SO3H sites.