Ionic liquid-coated carbon nanotubes as efficient metal-free catalysts for the synthesis of chromene derivatives

Abstract

Efficient ionic liquid-coated carbon nanotubes (IL@CNTs) for the synthesis of chromene derivatives were developed. The characteristic features of IL@CNTs are that they are metal free and have positively charged surfaces. The catalytic activity of IL@CNTs was evaluated for the synthesis of chromene derivatives in water under sonothermal conditions, affording high yields of the desired products. The present process is an eco-friendly method for the synthesis of chromene derivatives, authenticated with a high EcoScale score, low E-factor, and metal-free conditions.