Claisen-Schmidt condensation catalyzed by basic ionic liquids

Six basic ionic liquids based on imidazolium were synthesized and used as catalysts in Claisen-Schmidt condensation. Hammett titration method was used to determine the basic strength and basic amount of these ionic liquids. Claisen-Schmidt condensation proceeded efficiently in these ionic liquids at room temperature and the ionic liquids could be reused at least 8 times without obvious activity loss.