Eco-friendly and recyclable ionic liquid–zinc chloride catalyst supported on graphene oxide from Nypa fruticans husk for green synthesis of 2-amino-3-cyanopyridine derivatives

Abstract

This study successfully demonstrates the application of GO/IL/Zn_xCl_y as a novel and environmentally friendly catalyst for the synthesis of 2-amino-3-cyanopyridine derivatives. Using Nypa fruticans husk as a precursor, a hybrid catalyst combining graphene oxide (GO), ionic liquid (IL), and zinc chloride-based species (Zn_xCl_y⁻) was produced, exhibiting higher catalytic activity, better selectivity, and outstanding recyclability. The structural and morphological features of GO/IL/Zn_xCl_y were investigated using FT-IR spectroscopy, Raman spectroscopy, XRD analysis, ICP-MS analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA) to elucidate their properties and establish the catalyst's efficiency and stability in organic synthesis. Under solvent-free conditions, we investigated the adaptability of the catalyst by effectively synthesizing of 2-amino-3-cyanopyridine derivatives with moderate to high yields (up to 57%), at 110 °C for 40 min. Analysis of the electronic and steric effects of different substituents revealed that electron-donating groups improve yield while electron-withdrawing groups reduce it, thereby offering insightful information for further catalyst modifications. The sustainability of the approach was determined by applying green chemistry criteria. The key indicators highlighting notable waste reduction and effective resource use were an E-factor of 1.40, an atom economy of 73.44%, and a process mass intensity (PMI) of 2.40. GO/IL/Zn_xCl_y provides a possible substitute for sustainable organic synthesis owing to its excellent catalytic efficiency, selectivity, recyclability, and eco-friendly nature.