نتایج جستجو برای: selective oxidation
تعداد نتایج: 311890 فیلتر نتایج به سال:
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...
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 ...
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...
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...
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...
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...
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...
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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