Greener Method to Obtain a Key Intermediate of Vitamin E over Cu-ZSM-5

The catalytic oxidation of 2,3,5-trimethylphenol was performed over transition metals modified ZSM-5 zeolites employing hydrogen peroxide as oxidant under mild reaction conditions. Catalysts samples were characterized by several techniques (XRD, FTIR, BET, AA) and cristallinity and orthorhombic symmetry were confirmed for all of them. Best catalytic results were obtained for Cu-ZSM-5 sample, so further activity studies were done over this material. 2,3,5-trimethyl-1,4-benzoquinone was obtained as the main product of the selective oxidation. Reaction parameters (nature of the solvent, hydrogen peroxide concentration, reaction time, catalyst mass, substrate initial concentration and reaction temperature) were evaluated to reach the optimum reaction conditions. According to the obtained results, an apparent activation energy of 52.33 kJ/mol was calculated.Fil: Saux, Clara. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Renzini, Maria Soledad. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Gómez, Silvina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Pierella, Liliana Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; Argentin

H2O2-Based oxidation of functionalized phenols containing several oxidizable sites to p-quinones using a mesoporous titanium-silicate catalyst

International audienc

Preparation of 2-methyl-1,4-naphthoquinone (vitamin K3) by catalytic oxidation of 2-methyl-1-naphthol in the presence of iron phthalocyanine supported catalyst

International audienceIron tetrasulfophthalocyanine (FePcS) supported catalyst was prepared by covalent grafting onto amino-modified silica by a novel practical one-pot method using activation of sulfonate groups of FePcS by triphenylphosphine triflate. FePcSeSiO2 in combination with tBuOOH behaved as an efficient catalyst for the oxidation of 2-methyl-1-naphthol to 2-methyl-1,4-naphthoquinone, vitamin K3. To optimise the catalytic system, the influence of different reaction parameters on the efficiency of this oxidation has been studied. Vitamin K3 was obtained with 59% selectivity at 96% conversion of 2-methyl-1-naphthol using only 0.5 mol% of catalyst. 18O labelling experiments indicate a non-radical mechanism for this oxidation

Mechanistic study on the oxidation of functionalized phenols and naphthols in Ti-MMM-2 / H2O2 and FePcS-SiO2 / tBuOOH systems

internationa

Kinetics and mechanism of the oxidation of alkyl substituted phenols and naphthols with tBuOOH in the presence of supported iron phthalocyanine

BIOVERT+ASO:IVA:OZANon

Solvent-free allylic oxidation of alkenes with O-2 mediated by Fe- and Cr-MIL-101

BIOVERT+ISK:ASOCatalytic properties of Fe-MIL-101 and Cr-MIL-101 metal-organic frameworks in the solvent-free oxidation of cyclohexene and alpha-pinene with molecular oxygen have been explored. Both catalysts allow alkene oxidation under mild conditions (1 bar O-2, 40-60 degrees C) and afford allylic oxidation products. The nature of catalysis and the product distribution strongly depend on the nature of the transition metal. Cr-MIL-101 behaves as truly heterogeneous catalyst to give predominantly alpha,beta-unsaturated ketones. Catalysis over Fe-MIL-101 has true heterogeneous nature only at 40 degrees C, producing mainly 2-cyclohexene-1-ol. At 50-60 degrees C, iron leaching into solution occurs, leading to cyclohexenyl hydroperoxide as the major product. Under optimal conditions, both catalysts can be reused several times without suffering a loss of the catalytic properties. Rate-retarding and rate-accelerating effects of inhibitors and initiators, respectively, indicate radical chain mechanism. Different pathways for transformation of hydroperoxide have been suggested to rationalize the observed differences in the reaction selectivities over Cr- and Fe-MIL-101. (c) 2012 Elsevier Inc. All rights reserved

Allylic oxdation of alkenes with molecular oxygen catalyzed by porous coordination polymers Fe-MIL-101 and Cr-MIL-101

BIOVERT+ISK:ASOThe catalytic performances of Cr-MIL-101 and Fe-MIL-101 porous coordination polymers have been investigated in the allylic oxidation of alkenes, including natural terpenes, with molecular oxygen (1 atm) under mild solvent-free conditions. Both catalysts remain stable under optimal conditions (40A degrees C for Fe-MIL-101 and 60A degrees C for Cr-MIL-101) and can be recycled, at least, four times without loss of the catalytic properties. Fe-MIL-101 favours the formation of unsaturated alcohols, while Cr-MIL-101 mediates the formation of unsaturated ketones. The oxidation process involves the formation of alkene hydroperoxide via conventional radical chain process and its further transformations over the MIL-101 catalysts. The mechanism of the hydroperoxide transformation strongly depends on the metal nature

Efficient epoxidation of olefins by H2O2 catalyzed by iron "helmet" phthalocyanines

BIOVERT:RAFFINAGE+ISK:EKU:PAF:ASOHigh yields of epoxides were obtained in the oxidation of a large range of olefins using 1.2-2 equiv. of H2O2 in the presence of iron helmet phthalocyanines. The involvement of high-valent iron oxo species was evidenced using cryospray mass spectrometry

Hydrocarbon oxidation over Fe- and Cr-containing metal-organic frameworks MIL-100 and MIL-101-a comparative study

SSCI-VIDE+CDFA+ISK:IVA:ASOInternational audienceCatalytic properties of Fe- and Cr-based metal-organic frameworks (MOFs) MIL-100 and MIL-101 have been assessed in two liquid-phase reactions: solvent-free allylic oxidation of alkenes (cyclohexene, alpha- and beta-pinenes) with molecular oxygen and oxidation of anthracene (AN) with tert-butyl hydroperoxide(TBHP). In the oxidation of alkenes, the product selectivity strongly depends on the nature of metal (Fe or Cr) but, for the same metal, only slightly differs for the MIL-100 and MIL-101 structures. The Fe- containing MOFs afford the formation of unsaturated alcohols while Cr-based MOFs give mainly unsaturated ketones. Both Cr-MIL-100 and Cr-MIL-101 favor decomposition of cyclohexenyl hydroperoxide to produce 2-cyclohexen-1-one with 67-69% selectivity. Stability toward destruction reduced in the order Cr-MIL-101, Cr-MIL-100 > Fe-MIL-100 > Fe-MIL-101. In the oxidation of anthracene over both Cr-MOFs and Fe-MIL-101, the selectivity toward 9,10-anthraquinone (AQ) attained 100% at 92-100% AN conversion. The turnover frequency (TOF) decreased in the order Cr-MIL-101 > Fe-MIL-101 > Cr-MIL-100 > Fe-MIL-100. Cr-MIL-101 revealed superior catalytic performance in terms of AN conversion, AQ selectivity and TOF. Nearly quantitative yield of AQ was obtained after 1.5 h at 100 degrees C in chlorobenzene as solvent. No leaching of active metal occurred under optimal reaction conditions and the MOFs could be recycled several times without deterioration of the catalytic properties. (C) 2014 Elsevier B.V. All rights reserved