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.

摘要

本研究以烟酸和 H ₃ PW ₁₂ O ₄₀为前驱体合成了 Keggin 型磷钨酸盐基离子液体 [HOOCC ₅ H ₄ NH] ₃ PW ₁₂ O ₄₀，并通过 FT-IR、¹ H NMR、¹³进行了表征。 C NMR、XRD、TGA 和 DTG 分析。然后，[HOOCC ₅ H ₄ NH] ₃ PW ₁₂ O ₄₀被用作一种高效且环保的催化剂，用于在 120°C 无溶剂条件下通过醛和双甲酮的双组分反应合成呫吨二酮。方便的后处理过程、温和的反应条件、高收率和实际反应时间短是该合成方法的具体优点。此外，所设计的离子液体被高效回收并重复使用四次，催化能力没有进一步降低。