Synthesis of KOH/SnO2 solid superbases for catalytic Knoevenagel condensation

• KOH/SnO2 with superbasic sites up to 1.362 mmol g− 1 was prepared.
• The use of graphene oxide leads to regular nanoparticles and enhanced basicity.
• The catalyst shows high activity in Knoevenagel condensation under mild conditions.
• The result opens up a new route for the design of superbases using SnO2 as supports.

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 1.362 mmol g− 1, the 20 wt.%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.

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