Amorphous Carbon Bearing Sulfonic Acid Groups in Mesoporous Silica as a Selective Catalyst

Sulfonic acid group (SO3H)-bearing amorphous carbon/mesoporous silica composites were studied for use as solid acid catalysts. Sugar-derived amorphous carbon with SO3H cannot catalyze hydrophobic acid-catalyzed reactions, such as the dimerization of alpha-methyl styrene, because of the small surface area. However, SO3H-bearing sugar-derived amorphous carbon supported on mesoporous silica exhibits remarkable catalytic performance for the dimerization of alpha-methylstyrene. Under optimal conditions, the selectivity of the composite catalysts for unsaturated dimers exceeds 98%. Structural and reaction analyses revealed that SO3H-bearing carbon particles with large surface areas are formed in the mesopores and prevent intramolecular Friedel-Crafts alkylation, resulting in high catalytic activity.