3008-37-5Relevant articles and documents
Synthesis, characterization, DFT studies, and immobilization of cobalt(II) complex with N,N′,N″-tris(2-pyrimidinyl)dimethylentriamine on modified iron oxide as oxidation catalyst
Sharbatdaran, Masoomeh,Farzaneh, Faezeh,Larijani, Majid Mojtahedzadeh,Salimi, Alireza,Ghiasi, Mina,Ghandi, Mehdi
, p. 264 - 275 (2016/06/09)
[Co3(PDMT)Cl6] complex, in which PDMT is N,N′,N″-tris(2-pyrimidinyl)dimethylentriamine was prepared in cyclohexanol under hydrothermal condition. At first, the crystal structure of PDMT was solved based on the Rietveld method by using laboratory X-ray powder diffraction data. The molecular geometry of the ligand and complex were optimized by B3LYP method. In order to heterogenize the prepared complex, it was immobilized on the modified Fe3O4 nanoparticles with (3-aminopropyl)trimethoxysilane (APTMS). The prepared compound designated as Fe3O4SiO2-2APTMS[Co3(PDMT)Cl6] was found to successfully catalyze the epoxidation of cyclooctene, styrene, cyclohexene, trans-stilbene as well as oxidation of fluorene, diphenylmethane, ethylbenzene, adamantane, cyclohexane, cyclooctane and norbornene with TBHP as oxidant with 25-100% conversions and 18-100% selectivities. Ligand, complex and Fe3O4SiO2-2APTMS[Co3(PDMT)Cl6] were characterized by FT-IR, TEM, XRD, Mass, UV-Vis, DSC-TGA, NMR, GC and GC-Mass techniques.
Doped graphene as a metal-free carbocatalyst for the selective aerobic oxidation of benzylic hydrocarbons, cyclooctane and styrene
Dhakshinamoorthy, Amarajothi,Primo, Ana,Concepcion, Patricia,Alvaro, Mercedes,Garcia, Hermenegildo
, p. 7547 - 7554 (2013/07/11)
Nitrogen (N)-, boron (B)-, and boron,nitrogen (B,N)-doped graphene (G) act as carbocatalysts, promoting the aerobic oxidation of the benzylic positions of aromatic hydrocarbons and cyclooctane to the corresponding alcohol/ketone mixture with more than 90 % selectivity. The most active material was the co-doped (B,N)G, which, in the absence of solvent and with a substrate/(B,N)G ratio of 200, achieved 50 % tetralin conversion in 24 h with a alcohol/ketone selectivity of 80 %. An FT-Raman spectroscopic study of a sample of (B,N)G heated at 100 °C in the presence of oxygen revealed new bands that disappeared upon evacuation and that have been attributed to hydroperoxide-like species formed on the G sheet based on the isotopic shift of the peak from 819 to 779 cm-1 when 18O2 was used as the oxidizing reagent. Furthermore, (B)G and (N)G exhibited high catalytic activity in the aerobic oxidation of styrene to benzaldehyde (BA) in 4 h. However, the product distribution changed over time and after 10 h a significant percentage of styrene oxide (SO) was observed under the same conditions. The use of doped G as catalyst appears to offer broad scope for the aerobic oxidation of benzylic compounds and styrene, for which low catalyst loading, mild reaction temperatures, and no additional solvents are required. Oxidation at graphene: Boron- and nitrogen-doped graphenes are excellent catalysts for promoting the oxidation of benzylic hydrocarbons, cyclooctane, and styrene with molecular oxygen at 0.5 wt % under atmospheric pressure and solvent-free conditions (see figure). Copyright
Scope, kinetics, and mechanistic aspects of aerobic oxidations catalyzed by ruthenium supported on alumina
Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 4353 - 4361 (2007/10/03)
The Ru/Al2O3 catalyst was prepared by modification of the preparation of Ru(OH)3·nH2O. The present Ru/Al 2O3 catalyst has high catalytic activities for the oxidations of activated, nonactivated, and heterocyclic alcohols, diols, and amines at 1 atm of molecular oxygen. Furthermore, the catalyst could be reused seven times without a loss of catalytic activity and selectivity for the oxidation of benzyl alcohol. A catalytic reaction mechanism involving a ruthenium alcoholate species and β-hydride elimination from the alcoholate has been proposed. The reaction rate has a first-order dependence on the amount of catalyst, a fractional order on the concentration of benzyl alcohol, and a zero order on the pressure of molecular oxygen. These results and kinetic isotope effects indicate that β-elimination from the ruthenium alcoholate species is a rate-determining step.
