Heteropolyacid-Based Ionic Liquid [HOOCC₅H₄NH]₃PW₁₂O₄₀ as the Eco-Friendly Catalyst for the One-Pot Synthesis of Xanthenediones under Solvent-Free Conditions

Abstract

In this study, Keggin-type phosphotungstate-based ionic liquid [HOOCC₅H₄NH]₃PW₁₂O₄₀ was synthetized using nicotinic acid and H₃PW₁₂O₄₀ as precursors and characterized via FT-IR, ¹H NMR, ¹³C NMR, XRD, TGA, and DTG analyses. Then, [HOOCC₅H₄NH]₃PW₁₂O₄₀ was utilized as a highly effective and eco-friendly catalyst for the synthesis of xanthenediones through two-component reaction of aldehydes and dimedone under solvent-free conditions at 120 °C. The convenient work-up procedure, mild reaction conditions, high yields, and practically short reaction times were the specific merits of the synthetic method. In addition, the designed ionic liquid was recycled efficiently and reused four times without further decrease in the catalytic ability.

Keywords:

• Catalyst
• hetropolyacid
• ionic liquid
• xanthenediones

Acknowledgement

We gratefully thank Islamic Azad University, Central Tehran Branch.

Disclosure statement

There are no conflicts of interest.