Efficient cyclohexane oxidation with hydrogen peroxide catalysed by a C-scorpionate iron(II) complex immobilized on desilicated MOR zeolite

Abstract

Abstract:The hydrotris(pyrazol-1-yl)methane iron(II) complex [FeCl2{eta(3)-HC(pz)(3)}] (Fe, pz = pyrazol-1-yl) immobilized on commercial (MOR) or desilicated (MOR-D) zeolite, catalyses the oxidation of cyclohexane with hydrogen peroxide to cyclohexanol and cyclohexanone, under mild conditions. MOR-D/Fe (desilicated zeolite supported [FeCl2{eta(3)-HC(pz)(3)}] complex) provides an outstanding catalytic activity (TON up to 2.90 x 10(3)) with the concomitant overall yield of 38%, and can be easy recovered and reused. The MOR or MOR-D supported hydrotris(pyrazol-1-yl)methane iron(II) complex (MOR/Fe and MOR-D/Fe, respectively) was characterized by X-ray powder diffraction, ICP-AES, and TEM studies as well as by IR spectroscopy and N-2 adsorption at -196 degrees C. The catalytic operational conditions (e.g., reaction time, type and amount of oxidant, presence of acid and type of solvent) were optimized. (C) 2013 Elsevier B.V. All rights reserved.

New Trends in Oxidative Functionalization of Carbon–Hydrogen Bonds: A Review

“…Polynuclear metal complexes containing voluminous organic [63,66,118,119,[129][130][131]186,[213][214][215][216][217][218][234][235][236][237][238][239][240][241] or siloxane [221][222][223][224][225][226][227][228] ligands are also very efficient in oxidations of organic compounds including saturated hydrocarbons with peroxides. For example, dinuclear copper complex 11 [221,224] and hexairon complex 15 (for the structure, see Figure 9) affording the products of cyclohexane oxidation in a very high yield of 46% (see Figure 10 [226]) can be considered as "inorganic models of methane monooxygenases."…”

“…New types of ligands have been proposed in recent decades which form efficient catalysts with transition metal ions. These ligands are: N-heterocyclic carbene (NHC) [202,203], pincer-like [204][205][206][207][208], redox-active ligands [209][210][211][212], and scorpionates [213][214][215][216][217][218].…”

Catalytic Performance of Fe(II)-Scorpionate Complexes towards Cyclohexane Oxidation in Organic, Ionic Liquid and/or Supercritical CO2 Media: A Comparative Study

“…The yield values achieved in acetonitrile were comparable to those previously obtained at room temperature [28] without any added promotor. Higher yields were reported in very different reaction conditions, such as when 1 was supported on carbon nanotubes or zeolites (total yield up to 38%) [32,33] or using microwave (MW) assistance (total yield of 33%) [12,34], always in the presence of pyrazinecarboxylic acid (Hpca) [32][33][34][35]. However, for the present study, to compare the catalysts' performances in different media, promotor-free conditions were preferred.…”

Zeolite-Y entrapped bivalent transition metal complexes as hybrid nanocatalysts: density functional theory investigation and catalytic aspects

“…In a recent industrial process, cyclohexane is oxidized at a temperature range of 150-170°C and pressure of 115-175 psi in the presence of homogeneous cobalt salt, where the conversion is very less (∼4%), and the process is environmentally hazardous (11,12). With the emphasis on environmentally benign catalytic oxidation of cyclohexane, several research groups have been designing various catalytic systems (13)(14)(15)(16)(17)(18)(19)(20).…”