نتایج جستجو برای: selective oxidation

تعداد نتایج: 311890  

Journal: :Journal of the American Chemical Society 2011
Jessica M Hoover Shannon S Stahl

Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O(2) as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)Cu(I)/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a...

Journal: :Chemical science 2015
Xianjun Lang Wei Hao Wan Ru Leow Shuzhou Li Jincai Zhao Xiaodong Chen

The selective oxidation of sulfides into sulfoxides receives much attention due to industrial and biological applications. However, the realization of this reaction with molecular oxygen at room temperature, which is of importance towards green and sustainable chemistry, remains challenging. Herein, we develop a strategy to achieve the aerobic oxidation of sulfides into sulfoxides by exploring ...

2003
Lidija Fras Karin Stana-Kleinschek Volker Ribitsch Majda Sfiligoj-Smole Tatjana Kreze

Complexometric titration was used to determine the carboxyl group content of a series of oxidatively treated (selective and non-selective oxidation) nature cellulose fibers (cotton). The results were correlated with those obtained from the conventional methylene blue method; both methods show an excellent correlation. The progress of the cellulose fibers oxidation was monitored using viscosimet...

Journal: :Molecules 2016
Roman V Ottenbacher Evgenii P Talsi Konstantin P Bryliakov

Non-heme iron(II) complexes are widespread synthetic enzyme models, capable of conducting selective C-H oxidation with H₂O₂ in the presence of carboxylic acid additives. In the last years, structurally similar manganese(II) complexes have been shown to catalyze C-H oxidation with similarly high selectivity, and with much higher efficiency. In this mini-review, recent catalytic and mechanistic d...

2013
Pyungwoo Jang Seungchan Shin Chip-Sup Jung Kwang-Ho Kim Kyu Seomoon

The possibility of a new technique for fabricating nanoparticles from thin films using selective oxidation in an atmosphere mixture of water vapor and hydrogen was investigated. Fe-5wt.%Al films were RF-sputtered and annealed in the atmosphere mixture at 900°C for up to 200 min, in order to oxidize aluminum selectively. Thermodynamics simulation showed that temperatures exceeding 800°C are nece...

2017
Linping Qian Zhen Wang Evgeny V Beletskiy Jingyue Liu Haroldo J Dos Santos Tiehu Li Maria do C Rangel Mayfair C Kung Harold H Kung

The ability of Au catalysts to effect the challenging task of utilizing molecular oxygen for the selective epoxidation of cyclooctene is fascinating. Although supported nanometre-size Au particles are poorly active, here we show that solubilized atomic Au clusters, present in ng ml-1 concentrations and stabilized by ligands derived from the oxidized hydrocarbon products, are active. They can be...

Journal: :ChemSusChem 2013
Jia Jia Dong Duenpen Unjaroen Francesco Mecozzi Emma C Harvey Pattama Saisaha Dirk Pijper Johannes W de Boer Paul Alsters Ben L Feringa Wesley R Browne

An efficient and simple method for selective oxidation of secondary alcohols and oxidation of alkanes to ketones is reported. An in situ prepared catalyst is employed based on manganese(II) salts, pyridine-2-carboxylic acid, and butanedione, which provides good-to-excellent conversions and yields with high turnover numbers (up to 10 000) with H2 O2 as oxidant at ambient temperatures. In substra...

o-Xylylenebis (triphenylphosphonium peroxymonosulfate) (1) was easily prepared from an aqueous solution of oxone and o-xylylenebis- (triphenylphosphonium bromide). This Compound (1) is a useful and selective reagent for conversion of oximes, semicarbazones and phenylhydrazones to the corresponding carbonyl compounds. The reaction was carried out under solvent-free conditions and in the presence...

2017
Valeria Dantignana Michela Milan Olaf Cussó Anna Company Massimo Bietti Miquel Costas

Methods for selective oxidation of aliphatic C-H bonds are called on to revolutionize organic synthesis by providing novel and more efficient paths. Realization of this goal requires the discovery of mechanisms that can alter in a predictable manner the innate reactivity of these bonds. Ideally, these mechanisms need to make oxidation of aliphatic C-H bonds, which are recognized as relatively i...

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