Carbon-coated mesoporous silica functionalized with sulfonic acid groups and its application to acetalization

The inner surface of mesoporous silica SBA-15 was coated by a homogeneous polycyclic carbon layer through controlled carbonization of furfuryl alcohol. The composite was subsequently functionalized with sulfonic acid (-SO₃H) groups to form a strong solid acid material, with a tunable acid site density in the range of 0.38-0.84 mmol/g by varying the thickness of the carbon layer. Structural analysis and reaction data revealed that the solid acid catalyst exhibited high reactivity towards the acetalization of aldehydes or ketones with alcohols because of the uniform carbon coating of the mesopores, high acid site density, and its mechanical stability.