Synthesis of KOH/SnO2 solid superbases for catalytic Knoevenagel condensation

Abstract

KOH/SnO2 solid superbases of specific morphology and uniform pore structure were synthesized. The SnO2 support was prepared by reflux digestion using graphene oxide as template and employed for the loading of KOH by means of grinding and thermal treatment. With base strength of 26.5≤H−<33.0 and superbasic sites of 1.362mmolg−1, the 20wt.%KOH/SnO2 catalyst exhibits excellent activity in Knoevenagel condensation under mild conditions. The catalytic efficiency is closely related to the base strength and the amount of superbasic sites. The findings disclose a new route for the synthesis of versatile solid superbases using SnO2 as supports.