Organo-niobate Ionic Liquids: Synthesis, Characterization and Application as Acid Catalyst in Pechmann Reactions

Abstract

The combinations of 1-butyl-3-methylimidazolium chloride with NbCl5 yieldedionic mixtures with different melting point temperatures and acidity depending on theniobium molar fraction. The mixtures were characterized by thermal (DSC) andspectroscopic (FT-IR and 1H NMR) analysis. The Pechmann reactions of different phenolswith ethylacetoacetate, producing coumarins, was used as model to evaluate the catalyticbehavior of these mixtures as acid Lewis catalyst. These reactions were carried out usingacidic mixtures of 60 mol%.