Use of immobilized transition metal complexes as recyclable catalysts for oxidation reactions with hydrogen peroxide as oxidant

Abstract

A tetradentate Schiff base (teta), obtained from triethylenetetramine and salicylaldehyde, has been covalently bonded to divinylbenzene cross-linked chloromethylated polystyrene. This chelating ligand, abbreviated as PS-teta (PS = polymeric support), reacts with metal chlorides (Cu 2? , Co 2? , and Ni 2? ) in methanol to give polymerbound transition metal complexes, PS-Cu(II)teta/(Cat-1), PS-Ni(II)teta/(Cat-2), and PS-Co(II)teta/(Cat-3), formation of which has been established by various physiochemical methods and spectroscopic techniques. The catalytic potential of these materials has been tested for the oxidation of various alkenes, alkanes, alcohols, and thioethers in the presence of 30% H 2 O 2 as an oxidant. At the same time, these catalysts are very stable and could be reused in oxidation reactions for more than five times without noticeable loss of their catalytic activity.

Cumene Hydroperoxide-Induced Epoxidation of Styrene Using Cu2O and PbO as Catalysts

“…All-inclusive data of the catalyst screening exercise are tabulated in Section S.4 of the Supporting Information. Cu +1 and Pb +2 oxides have been reported to be employed as catalysts in numerous studies on epoxidation, − but to the best of our knowledge, styrene epoxidation using any oxygen-inducing reagent under the catalytic influence of oxides of Cu +1 and Pb +2 has never been reported prior to this work. Figure is also marked with the breakeven yield (∼18%)the minimum product yield in the proposed hydroperoxide-based scheme to match the profit earned from the conventional chlorohydrin-based scheme.…”

Recent Investigation on Epoxidation of Styrene with Hydrogen Peroxide by Heterogeneous Catalysis

“…Sk Manirul Islam et al [60] covalently bonded a tetradentate Schiff base (teta), obtained from triethylenetetramine and salicylaldehyde, to divinylbenzene cross-linked chloromethylated polystyrene for various epoxidation. Scheme 24 exhibited the preparation procedure.…”

CuII(Sal-Ala)/CuAlLDH Hybrid as Novel Efficient Catalyst for Artificial Superoxide Dismutase (SOD) and Cyclohexene Oxidation by H2O2

“…Hence, in recent years, a sustained research was carried out to develop novel heterogeneous oxidation catalysts [1,3,[14][15][16]. Schiff base complexes containing donor atoms such as oxygen and nitrogen were immobilized into different supports and have been used for oxidation reactions [17][18][19][20][21]. The lamellar double hydroxides (LDH)-based catalysis is of high interest for green and sustainable chemistry [22] since the LDHs are able to provide distinct nanometerscaled layers and interlayers for engineering them as active catalysts [23][24][25].…”