A novel ternary GO@SiO₂‐HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media

Abstract

A new solid acid catalyst, consisting of 12‐phosphotungstic heteropoly acid (HPW) supported on graphene oxide/silica nanocomposite (GO@SiO2), has been developed via immobilizing HPW onto an amine‐functionalized GO/SiO2 surface through coordination interaction (GO@SiO2‐HPW). The GO@SiO2‐HPW nanocomposite was characterized by Fourier transform infrared (FT‐IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X‐ray diffraction (XRD). The prepared nanocomposite could be dispersed homogeneously in water and further used as a heterogeneous, reusable, and efficient catalyst for the synthesis of benzimidazoles and benzothiazoles by the reaction of 1,2‐phenelynediamine or 2‐aminothiophenol with different aldehydes.

Recent Progress on Functionalized Nanoporous Heteropoly Acids: From Synthesis to Applications

“…[33] The acidity of the final product depends on the nature of support, HPA loading and synthesis procedure. Acidic or neutral substrates such as MOF, [34] SiO 2 , [35] TiO 2 , [36] ZrO 2 , [37] Al 2 O 3, [38] porous polymers, [39] graphene oxide [40] or carbon [41] based materials have been reported to be proper supports, while alkaline supports may decompose the HPA structure. [42] Impregnating HPAs into these supports leads to a considerable surface area increase, thereby providing more active sites to accommodate larger numbers of HPAs particles.…”

Difunctional Silicon Dioxide Combined with Graphene Oxide Nanocomposite to Enhance the Anticorrosion Performance of Epoxy Coatings

“…The first thing that comes into play is layered GO when the corrosive medium begins to penetrate the coating. It acts as a physical barrier by extending the path of the corrosive medium to the metal surface for delaying its arrival on the metal surface. − Subsequently, BTA will be released from the mesoporous SiO 2 nanovessel when the pH value changes due to electrochemical corrosion to adsorb on the corrosion site and produce a film to protect the metal matrix. In order to obtain BTA-SiO 2 -GO nanocomposites, the process shown in Scheme is adopted.…”

Graphene oxide incorporated amino‐functionalized iron terephthalate composite as a heterogeneous Fenton‐like catalyst

“…[19] Graphene oxide (GO), due to it tremendous electronic mobility, has been studied as post-synthetic modifier in order to enhance the functionality of original material for various applications. [5,7,[22][23][24][25][26][27] GO is the oxidized form of graphene consisting of twodimensional graphene sheet with oxygen functional groups, such as epoxide and carboxylic. [28][29][30] GO is usually synthesized by Hummer's method through chemical oxidation of graphite, followed by the exfoliation of graphite oxide.…”