Graphene‐Oxide‐Supported SO 3 H‐Functionalized Imidazolium‐Based Ionic Liquid: Efficient and Recyclable Heterogeneous Catalyst for Alcoholysis and Aminolysis Reactions

Ionic liquids have been established as solvents and catalysts in a number of reactions due to their unique properties. In this study, we have synthesized sulfonic acid functionalized imidazolium based strongly acidic ionic liquid supported on graphene oxide (PTS−Im‐3@GO). PTS−Im‐3@GO was synthesized by grafting 1‐(4‐sulfobutyl)‐3‐(3‐propyltriethoxysilyl)imidazolium hydrogen sulfate onto graphene oxide (GO) by covalent bonds. The prepared PTS−Im‐3@GO was used for regio‐selective ring opening reaction of styrene oxide with isopropyl alcohol giving 95% conversion and 100% regio‐selectivity towards 2‐isopropoxy‐2‐phenylethan‐1‐ol at 50 °C. The activity of the said catalyst was compared with various heterogeneous catalysts such as GO, PTS−Im‐1@GO, PTS−Im‐2@GO, PTS−Im‐1, PTS−Im‐2, PTS−Im‐3, Hβ‐zeolite, and montmorillonite K‐10. Among all catalysts, PTS−Im‐3@GO showed good conversion towards the desired product. PTS−Im‐3@GO was characterized by FTIR, SEM, EDS, TGA, XRD, 29 Si NMR, XPS and CHNS analysis. Systematic studies demonstrated that PTS−Im‐3@GO had excellent catalytic activity and regio‐selectivity for the alcoholysis of epoxides rendering β‐alkoxy alcohols and aminolysis of epoxide giving β‐amino alcohols in very good yields. The protocol is clean and green.