Selective dehydration of sorbitol to 1,4-anhydro-D-sorbitol catalyzed by a polymer-supported acid catalyst

Novel polymer-supported Brønsted acid polymer catalysts have been successfully synthesized by radical polymerization, followed by a simple solvothermal route and ion exchange step. The as-synthesized co-polymers were characterized by Elemental Analysis, FT-IR spectroscopy, thermogravimetric analysis and scanning electron microscopy and then were employed as a heterogeneous catalyst for dehydration of sorbitol. Especially, the polymer catalysts have a unique advantage of adjustable Brønsted acidity, and the polymer with 1.82 mmol g−1 of Brønsted acidity was a very efficient catalyst for highly selective dehydration of sorbitol into 1,4-anhydro-D-sorbitol. The dehydration reaction can be completed within 4 h and the selectivity of 1,4-anhydro-D-sorbitol achieved 90%. Moreover, the present catalysts resisted acid-leaching and can be recycled in five consecutive cycles without obvious loss of activity.