Applications of heteropoly acids as heterogeneous catalysts

Direct Amide Formation via Carbamoylation of Aromatic Bromides using Heteropoly Acid and UV‐Light

“…The electronrich CÀ C σ-bonds were advanced, and the carbamoylation reactivity was excellent. The aromatic halides Br (7), meta-Cl (8), ortho-Cl (9), fluorine (10) are moderately electron-withdrawing substituents, but only the slight possibility of carbamoylation could be confirmed due to the intervention of the second À Br, À Cl, and À F of each structure. Among the electron-withdrawing groups, only some groups such as cyanide (4), trifluoromethyl group (12), and methyl benzoate ( 14) can be synthesized, and nitrogen dioxide (11) and aldehyde (13) did not react.…”

“…Here, we focus on the development of efficient methods that are economical and eco‐friendly for the synthesis of benzoic amides (Figure 1). We found that using a heteropoly acid (HPA) with a Keggin structure (Figure 2) as a homogeneous photocatalyst [9] and a metal‐oxygen cluster [10] has many advantages [9b,11] . It is acidic, oxidative, and is important as a catalyst that enables effective oxidation through photoinduced photoredox reactions in the wavelength range of 200 to 500 nm [12] .…”

Catalytic Reduction of Aromatic Nitro Compounds in Aqueous Media using Silver Nanoparticles Embedded-Preyssler Functionalized Cellulose Biocomposite as a Green and Recoverable Catalyst

“…Solid heteropolyacids (HPAs) are green polymeric materials, containing the early transition metal cations, M (generally W, Mo and V) and a central heteroatom, X (Si, P, Ge, etc.) [33][34][35][36][37][38][39]. Possessing high thermal stability, robust acidity and structural flexibility, HPAs are used extensively as homogeneous catalysts, heterogeneous catalysts, or heterogeneous surface catalysts in various chemical reactions.…”

“…The Preyssler heteropolyanion, [NaP5W30O110] 14with 14 acidic protons is an effective superacid solid catalyst that can be utilized both in homogeneous and heterogeneous phases. Recent studies have been extensively concentrated on the designing of organicinorganic composites of HPAs and their applications in different reactions [33][34][35][36][37][38][39].…”