Facile synthesis of sulfonic acid-based ionic liquid-decorated magnetic halloysite as an efficient catalyst for the multicomponent synthesis of 2-amino 4 H pyran derivatives

Abstract

In the present research, a new magnetic halloysite nanoclay (Hal) modified with glutamine (Glu) and an ionic liquid (IL) containing sulfonic acid groups, denoted as Fe3O4 @Hal-Glu-EPI-SO3H IL, was successfully synthesized. The characterization of the synthesized nanocomposite was precisely accomplished by using different physicochemical techniques, including Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), and thermogravimetric analysis (TGA). The catalytic activity of the as-prepared catalyst was investigated in the synthesis of 4H-pyran derivatives through multicomponent reactions (MCRs) under reaction conditions. For optimizing the reaction, the key factors, including the amount of Fe3O4 @Hal-Glu-EPI-SO3H IL, type of solvent, reaction time and temperature were evaluated. The optimum conditions of model reaction were achieved using 0.02 g of catalyst in water solvent after 20 min at reflux temperature. According to the findings above, the results indicated that high-yield products (96%) are obtained during a short time. Moreover, the high catalytic activity of the Fe3O4 @Hal-Glu-EPI-SO3H IL was maintained for six cycles without significantly diminishing its performance.