▎ 摘　　要

Sulfonated reduced graphene oxide (rGO-SO3H, SRGO) was synthesized by introducing aryl diazonium salt of sulfanilic acid radicals onto chemically modified reduced graphene oxide (rGO) under sonication. SRGO catalyst was characterized by X-ray diffraction (XRD), Raman spectroscopy, solid state C-13 MAS NMR (C-13 SSNMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron spectroscopy (TEM), and X-ray photoelectron spectroscopy (XPS). SRGO was efficiently used as a reusable, metal-free, solid acid catalyst for the direct N-acetylation of amines with acetonitrile under sonication into the corresponding amides. Thus, the method could also serve as a novel convenient alternative for the other acetylation reactions under sonication to avoid using toxic substances such as acetic anhydride, acetyl chloride, and acetic acid. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.