55076-92-1

Upstream product

• 540-49-8 cis+trans-dibromoethylene 
• 110-83-8 cyclohexene 

Relevant academic research and scientific papers

H2O2-based selective oxidations by divanadium-substituted polyoxotungstate supported on nitrogen-doped carbon nanomaterials

In this work, we present a new methodology for the preparation of highly active, selective, leaching-tolerant and recyclable catalysts on the basis of polyoxometalates (POM) and nitrogen-doped carbon nanomaterials. A divanadium-substituted γ-Keggin phosphotungstate [γ-PW10O38V2(μ-O)(μ?OH)]4? (PV2), was immobilized on two types of supports – N-doped carbon nanofibers (N-CNFs) having herring-bone packing of graphite layers and bamboo-like N-doped carbon nanotubes (N-CNTs). Two series of catalysts have been prepared and characterized by elemental analysis, N2 adsorption, TEM, XPS and FTIR techniques. Their catalytic performance was assessed in the liquid-phase selective oxidation of two representative organic substrates, 2,3,6-trimethylphenol and cyclohexene, with aqueous H2O2 as the green oxidant. The presence of nitrogen in the supports ensures strong binding and quasi-molecular dispersion of POM on the carbon surface, which is crucial for the catalytic performance and catalyst stability. The catalysts reveal truly heterogeneous nature of the catalysis and can be easily recovered and reused without loss of the catalytic performance. The morphology of the support has a significant impact on the catalytic performance: the supported PV2 catalysts prepared using N-CNTs are more active and, in general, more selective than the catalysts prepared with N-CNFs.

Catalytic cyclohexene oxidation in the nano channels of a copper silicate material

Herein we examined the catalytic activity of the copper silicate material SGU-29 for the aerobic partial oxidation of cyclohexene under mild conditions (1 bar of O2 at 70 °C). In particular, the catalytic properties of the active sites provided by [CuO4] square planar units in SGU-29 were investigated for cyclohexene oxidation to generate three main oxidation products (i.e., 2-cyclohexene-1-ol, 2-cyclohexene-1-one, and cyclohexene hydroperoxide). Based on the molecular sieving effect of SGU-29, we especially investigated the intrazeolitic reaction, a catalytic cyclohexene oxidation occurring only in nanochannels of SGU-29. A conversion yield of 42% was obtained for the aerobic cyclohexene oxidation occurring only in SGU-29 nanochannels under 1 bar of O2 at 70 °C for 12 h. We demonstrated unequivocally that catalysis occurred only within the inner channels of SGU-29, rather than on its external surface or within the solvent, and we highlighted the special role of [CuO4] square planar units in catalysis.

An Improved Catalytic Performance of Fe(III)-promoted NHPI in the Oxidation of Hydrocarbons to Hydroperoxides

Abstract: N-hydroxyphthalimide (NHPI) is a promising catalyst in aerobic oxidation of hydrocarbons to corresponding hydroperoxides. We have found that a trace amount of Fe(benz)3 or Fe(acac)3 (in concentration of less than 10?1 mmol/l and with the ratio of Fe(III): NHPI = 1:500) considerably accelerates the oxidation of cyclohexene and ethylbenzene, while retaining the selectivity to hydroperoxides at a level of 90%. As a consequence, the reaction temperature could be lowered down to 50–60?°C. The promoting effect of the additives was attributed to the ability of Fe(III) complexes to generate phthalimido-N-oxyl radicals (PINO) without participation in any transformations of hydrocarbon intermediates and hydroperoxides, thus ensuring selective formation and stability of the hydroperoxides.

Highly efficient room-temperature oxidation of cyclohexene and d-glucose over nanogold Au/SiO2 in water

Silica-supported nanogold catalysts suspended in 30% hydrogen peroxide using ultrasound are highly active and selective for cyclohexene and d-glucose oxidation at room temperature. In these conditions a polar reactant, D-glucose, can be efficiently and directly converted with 100% yield using this system, while a conversion of apolar cyclohexene is limited by the addition of a surfactant improving cosolubility in the system and/or catalyst/support wettability. To our best knowledge this is the first time that hydrogen peroxide has been used efficiently in association with a gold catalyst for the selective oxidation of cyclohexene in a biphasic system.

C2 molecule: formation from bromoacetylene and reactions with cyclohexene or 2,3-dimethyl-2-butene

The C2 molecule (1,2-ethynediyl) has been prepared by dehydrohalogenation of 1,2-dibromoethylene with an excess of potassium tert-butoxide in 2,3-dimethyl-2-butene as the solvent and the reagent. The major products of this reaction were 2,3-dim

RELATIONSHIP BETWEEN CATALYTIC ACTIVITY OF COPPER(II) CHELATES AND THE NATURE OF REMOTE SUBSTITUENTS IN THE LIGANDS

The catalytic activity of Cu(II) chelates with bi- and tetradentate hydrazonimine ligands bearing various substituents in the para position of the benzene ring of the hydrazone fragment was studied with model liquid-phase oxidation of cyclohexene with molecular oxygen as an example.The apparent rate constants corresponding to the initial and stationary portions of the kinetic curves were calculated.Introduction of electron-withdrawing nitro group into the benzene ring of the hydrazone fragment was found to only slightly affect the catalytic properties of the chelate, the character pf this effect depending upon the nature of the substituent in the γ position of the quasiaromatic chelate ring.A correlation between the catalytic and electrochemical properties of the complexes was revealed.