Sulfated SO4 2−/WO3 as an efficient and eco-friendly catalyst for solvent-free liquid phase nitration of toluene with NO2

Facile design of a WO3 nanorod-decorated graphene oxide 1D–2D nanocatalyst for the synthesis of quinoline and its derivatives

“…The peak that appeared at 1540 cm −1 for WO 3 has been attributed to the Brønsted acidic site owing to the formation of the pyridinium ion (pyridine adsorbed on protonic acidic site). 67 This may be due to the interaction of the pyridine with the Brønsted acidic sites of the catalyst. 68 The peaks appearing at 1505 and 1450 cm −1 for WO 3 have been assigned to the adsorbed pyridine on the Lewis acidic site.…”

“…The development of Lewis acid sites on WO 3 was related to the coordinatively unsaturated W 6+ species on the surface and the Brønsted sites are due to the formation of hydroxyl groups by protonating terminal W–O bond on the catalyst surface. 67,71…”

Synthetic Protocols for Aromatic Nitration: A Review

“…Significant features of this new approach are the solvent-free system and reusable catalysts make this approach green and clean. [43] A Potassium Periodate/NaNO 2 /KHSO 4 treated Nitration of Aromatic compounds that have been developed by Sriram and co-workers (Scheme 35). For comparative study authors used two different conditions conventional and microwave-assisted (MWAS).…”

“…However, from the obtained results SO 4 −2 /WO 3 gave good results in term of yield for the desired product. Significant features of this new approach are the solvent‐free system and reusable catalysts make this approach green and clean [43] …”

The application of nitrogen oxides in industrial preparations of nitro compounds

“…Nitration reactions to form C‐N bonds have been widely used for the preparation of nitro compounds in numerous areas of applied research . Owing to the widespread presence of nitro compounds in pharmaceuticals, natural products, organic intermediates, catalysts, and high energy density materials, the application of this process has been exceptionally broad. However, based on the principles of green chemistry, most industrial nitration processes are less environmentally‐friendly because they use nitric acid, nitrates, and nitrous esters as nitrating agents .…”