Convenient synthesis and application of novel bi-SO3H-functionalized ionic liquids based on piperazinium

In this article, series of novel bi-SO3H-functionalized ILs were synthesized using simple, efficient and economic procedure. Hammett method had been used to determine the acidity order of these ionic liquids, and the acidities of bi-SO3H-functionalized ILs were stronger than that of traditional single-SO3H-functionalized ILs. Their catalytic activities in the synthesis of N-(3-phenyl)-3-oxo-1-(phenylpropyl)acetamide were investigated and they were consistent with their acidities.