PREPARATION, CHARACTERIZATION AND UTILIZATION OF A NOVEL TRIFLUOROACETIC ACID SUPPORTED STARCH/GRAPHENE OXIDE GREEN NANOCOMPOSITE FOR EFFICIENT SYNTHESIS OF 2,4,5-TRISUBSTITUTED IMIDAZOLES

This study reports on the production, characterization, and application of a novel starch/graphene oxide nanocomposite for rapid synthesis of 2,4,5-trisubstituted imidazoles. To this end, graphene oxide was first functionalized by 1,8-diamino-3,5-dioxaoctane under appropriate conditions. Starch, functionalized graphene oxide, and 3-aminopyridine nanocomposite were then prepared from the reaction of starch with graphene oxide functionalized with 1,8-diamino-3,5-dioxaoctane in the presence of hexamethylene diisocyanate (HDMI) as a binding agent and 3-aminopyridine. Then, trifluoroacetic acid was added, giving rise to an acid-supported starch and graphene oxide nanocomposite. To examine the efficiency of the nanocomposite, 2,4,5-trisubstituted imidazoles were efficiently synthesized in the presence of the nanocomposite using benzil, aryl aldehyde, and ammonium acetate under solvent-free condition within a short reaction time. The moderate conditions, fast reaction rates, ease of purification, solvent-free condition, use of a green catalyst (nanocomposite), and environmental friendliness are among the advantages of the proposed synthesis method. The recoverability and durability of the catalyst were confirmed after five runs with no significant loss of activity. Thus, this research presents a novel nanocomposite based on starch and graphene oxide with superior properties.