Sorbitol Cyclodehydration to Isosorbide Catalyzed by Acidic Carbon Obtained from Reaction By-Product

A carbonaceous solid acid catalyst obtained from by-products of sorbitol dehydration process, was prepared via facile onestep carbonization and sulfonation method. The results of various characterization technologies showed that as-prepared acidic carbon bearing -SO3H, -COOH and -OH groups with Bronsted acid sites was effective for solvent-free dehydration of sorbitol to produce isosorbide. Full complete sorbitol conver-sion with 72.1% isosorbide yield was achieved at 170 degrees C after 2 h reaction. Catalyst could be used for three cycles retaining the most of its initial catalytic activity. Importantly, the catalyst and reaction by-products in this process could be easily recycled and facilely utilized, offering sustainable process in production of isosorbide from sorbitol.