▎ 摘　　要

A novel graphene oxide (GO)-based catalyst with 5-sulfobenzoic acid-functional groups is synthesized. Graphene oxide is covalently functionalized by partly safe chemical compounds through aryl diazonium salts to give 5-sulfobenzoic acid-functionalized graphene oxide (SBGO). Combined characterizations of X-ray powder diffraction, field emission scanning electron microscopy, and also transmission electron microscopy techniques show that SBGO has a nanosheet structure. Energy-dispersive X-ray spectroscopy survey discloses that SBGO catalyst contains only O and S heteroatoms which confirms it is green, sustainable, and environmentally benign heterogeneous catalyst. Fourier transform infrared spectroscopy displays that SBGO has a S=O bond. Acid-base titration demonstrates that the acidic concentration of the catalyst is 2.8 mmol H+ g(-1). The Raman spectrum of SBGO shows increased D/G bonds intensity ratio compared to that in graphene oxide which confirms the functionalization of graphene oxide. Thermogravimetric curves show the decomposition temperature (230 A degrees C) of the SBGO (a weight loss of about 10%) that attributed to the sulfonic groups decomposition. This catalyst is applied for the multicomponent synthesis of polyhydroacridine derivatives and high activity of solid acid catalyst was observed even after nine runs, which is referred to the stable functionalized groups on the catalyst.