Enthalpies of solution oft-butyl chloride and bromide and carbon tetrachloride and tetrabromide in alcohols

Standard enthalpies of solution of t-BuX and CX₄ (X=Cl and Br) in several alcohols are reported as measured by a calorimetric method. The corresponding transfer functions from the gas phase were calculated.     

Highly selective copper‐catalyzed oxidation of benzyl alcohols to aromatic aldehydes in water at room temperature

Water‐soluble 2N2O–Cu(II) complexes were synthesized and used for the catalytic oxidation of benzylic alcohols to the corresponding aldehydes in pure water resulting in high yields of up to 94%. Importantly, the catalytic system exhibits a wide substrate scope, high functional group tolerance and can be reused directly for subsequent reaction cycles. Using this catalytic system, the product 4‐methylbenzaldehyde can be produced on a multi‐gram scale and in the complete absence of any organic solvent, surfactant or phase transfer reagent. Copyright © 2016 John Wiley & Sons, Ltd.     

Cobalt phthalocyanine catalyzed aerobic oxidation of secondary alcohols: an efficient and simple synthesis of ketones

A variety of activated and non-activated secondary alcohols have been efficiently oxidized to their corresponding ketones in excellent yields with molecular oxygen using cobalt phthalocyanine as catalyst in the presence of powdered potassium hydroxide.     

Selective photocatalytic oxidation of alcohols to aldehydes in water by TiO2 partially coated with WO3

Semiconductor TiO₂ particles loaded with WO₃ (WO₃/TiO₂), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at λ>350 nm. The WO₃/TiO₂ catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO₂. In particular, a catalyst loading 7.6 wt % WO₃ led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO₂ surface of the catalyst, which is active for oxidation, is partially coated by the WO₃ layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO₂ surface. This suppresses subsequent decomposition of the aldehyde on the TiO₂ surface and results in high aldehyde selectivity. The WO₃/TiO₂ catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.     

Chromium(VI) supported and entrapped on silica and zirconia as recyclable materials for oxidation of alcohols

Oxidation of alcohols have been realized with Cr(VI) oxide supported or entrapped, via sol-gel methodology, on silica and zirconia. These materials were easily recovered from the reaction mixture without leaching of chromium in solution. Moreover, recycling studies have indicated that they can be regenerated by calcinations at 400-600°C or by treatment with ozone at room temperature. In the case of Cr(VI) entrapped into silica matrix up to 18 oxidation cycles have been realized without loss in activity.     

Generally applicable and efficient esterification of aldehydes with alcohols catalyzed by cyclopalladated ferrocenylimine

The palladacycle‐catalyzed esterification of a variety of aldehydes with alcohols was developed. This reaction allows formation of esters in moderate to excellent yields not only for various aldehydes but also alcohols. In addition, the esterification could proceed well under mild conditions with a low catalyst loading of 0.0625 mol%. Copyright © 2013 John Wiley & Sons, Ltd.     

N-羟基邻苯二甲酰亚胺和二氧化锰高效催化对硝基甲苯氧化

采用N-羟基邻苯二甲酰亚胺(NHPI)和二氧化锰(MnO2)作为催化剂催化对硝基甲苯的氧化反应以制备对硝基苯甲酸;对反应条件进行了优化.结果表明,采用10%(与原料的摩尔比)NHPI和10%(与原料的摩尔比)MnO2作为催化剂,在110℃、氧气压力0.4 MPa下反应4 h,对硝基甲苯的转化率为97%,对硝基苯甲酸的分...     

Peroxidative catalytic oxidation of alcohols catalyzed by heterobinuclear vanadium(V) complexes using H2O2 as terminal oxidizing agents

Here we report the catalytic oxidation of benzylic alcohol, hetero‐aryl alcohols and propargylic alcohols to their corresponding carbonyl compound using heterobimetallic sodium‐dioxidovanadium(V) complexes. The present catalytic oxidation studies proceed at 70 °C using H₂O₂ as terminal oxidant. During the whole process, the complexes react with hydrogen peroxide to form peroxo‐vanadium(V) species. The present study shows the heterogeneity of pre‐catalyst which could be easily recovered and moreover isolation of product is very simple.     

Aerobic photocatalytic oxidation of activated benzylic and allylic alcohols to carbonyl compounds catalyzed by molecular iodine

An efficient, selective and environmentally benign photocatalytic system in acetonitrile has been developed for aerobic oxidation of activated benzylic and allylic alcohols into their corresponding aldehydes and ketones without the need for a transition metal in moderate to excellent yields with a catalytic amount of iodine. Very high inter- and intramolecular chemoselectivities are observed when benzylic OH groups are oxidized in the presence of aliphatic (nonbenzylic) hydroxyls.     

Efficient synthesis of carbonyl compounds: oxidation of azides and alcohols catalyzed by vanadium pentoxide in water using tert-butylhydroperoxide

Catalytic amount of vanadium reagent with tert-butylhydroperoxide as the oxidant was found to be an excellent oxidizing agent in aqueous medium. Vanadium pentoxide with aq tert-butylhydroperoxide readily oxidizes primary benzylic azides to the corresponding acids and secondary benzylic azides to the corresponding ketones in excellent yields. Further, vanadium pentoxide and aq tert-butylhydroperoxide combination turned out to be an effective catalyst for the oxidation of alcohols. Using vanadium pentoxide and aq tert-butylhydroperoxide primary alcohols were oxidized to the corresponding acids, whereas secondary alcohols underwent a smooth transformation to furnish corresponding ketones in excellent yields. All the oxidations are performed in water.     

A mild and efficient oxidation of alcohols to aldehydes and ketones with periodic acid catalyzed by chromium(III) acetylacetonate

Chromium(III) acetylacetonate was found to be an efficient catalyst (10 mol%) for the oxidation of alcohols to aldehydes and ketones with periodic acid (1.5 equiv.) in acetonitrile at room temperature.     

Thiol‐functionalized fructose‐derived nanoporous carbon as a support for gold nanoparticles and its application for aerobic oxidation of alcohols in water

Gold nanoparticles supported on thiol‐functionalized fructose‐derived nanoporous carbon (AuNPs@thiol‐Fru‐d‐NPS) were found to be a simple bench‐top, biocompatible, recyclable and selective catalytic system for the aerobic oxidation of various types of alcohols into their corresponding aldehydes and ketones at room temperature under the environmentally friendly conditions with excellent yields. Copyright © 2014 John Wiley & Sons, Ltd.     

Oxidation of alkanes and alcohols with hydrogen peroxide catalyzed by complex Os3(CO)10(µ‐H)2

Trinuclear carbonyl hydride cluster, Os₃(CO)₁₀(µ‐H)₂, catalyzes oxidation of cyclooctane to cyclooctyl hydroperoxide by hydrogen peroxide in acetonitrile solution. The hydroperoxide partly decomposes in the course of the reaction to afford cyclooctanone and cyclooctanol. Selectivity parameters obtained in oxidations of various linear and branched alkanes as well as kinetic features of the reaction indicated that the alkane oxidation occurs with the participation of hydroxyl radicals. A similar mechanism operates in transformation of benzene into phenol and styrene into benzaldehyde. The system also oxidizes 1‐phenylethanol to acetophenone. The kinetic study led to a conclusion that oxidation of alcohols does not involve hydroxyl radicals as main oxidizing species and apparently proceeds with the participation of osmyl species, ‘Os?O’. Copyright © 2010 John Wiley & Sons, Ltd.     

Stereo- and regioselective synthesis of 1,3-diaryl-3-chloro-1-propanols via the reaction of aryl aldehydes with styrene and (E)-β-methylstyrene

Reactions of aryl aldehydes with styrene and (E)-β-methylstyrene in the presence of phenylboron dichloride regioselectively generate 1,3-diaryl-3-chloro-1-propanols and 1,3-diaryl-3-chloro-2-methyl-1-propanols in good to excellent yields with high stereoselectivity.     

Green oxidation of alcohols by using hydrogen peroxide in water in the presence of magnetic Fe3O4 nanoparticles as recoverable catalyst

Magnetically nano Fe₃O₄ efficiently catalyzes green oxidation of primary and secondary benzylic and aliphatic alcohols to give the corresponding carbonyl products in good yields. The reactions were carried out in an aqueous medium in the presence of hydrogen peroxide as an oxidant at 50°C. In addition, the magnetically nano Fe₃O₄ catalyst could be reused up to four runs without any significant loss of activities. Catalyst was characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, thermogravimetric analysis, vibrating sample magnetometer, and IR.     

Effective catalytic oxidation of alcohols and alkenes with monomeric versus dimeric manganese(II) catalysts and t‐BuOOH

Two new Mn(II) complexes, [Mn(C₆H₅COO)(H₂O)(phen)₂](ClO₄)(CH₃OH) ( 1 ) and [Mn₂(μ‐C₆H₅COO)₂(bipy)₄]?2(ClO₄) ( 2 ) (phen = 1,10‐phenanthroline; bipy = 2,2′‐bipyridine), were synthesized and characterized using UV–visible and infrared spectroscopies and single‐crystal X‐ray diffraction analyses. Complexes 1 and 2 have six‐coordinate octahedral geometry around the Mn(II) centre. Complex 1 is a monomer and consists of a deprotonated monodentate benzoate ligand together with two neutral bidentate amine ligands (phen) and a water molecule. Complex 2 has a dinuclear structure in which two Mn(II) ions share two carboxylate groups, adopting a two‐atom bridging mode, and two chelated bipy ligands. Both complexes catalyse the oxidation of alcohols and alkenes in a homogeneous catalytic system consisting of the Mn(II) complex and tert‐butyl hydroperoxide (TBHP) in acetonitrile. The system yields good to quantitative conversions of various alkenes and alcohols, such as styrene, ethylbenzene and cyclohexene to their corresponding ketones, and primary alcohols and 1‐octanol, 1‐heptanol, cyclohexanol, benzyl alcohols and cinnamyl alcohol to their corresponding aldehydes and carboxylic acids. Complexes 1 and 2 exhibit very high activity in the oxidation of cyclohexene to cyclohexanone (ca 80% selectivity) as the main product (ca 94% conversion in 1 h) and of cinnamyl alcohol to cinnamaldehyde (ca 64% selectivity) as the main product (ca 100% conversion in 0.5 h) with TBHP at 70°C in acetonitrile. In addition, optimum reaction conditions were also determined for benzyl alcohol with complexes 1 and 2 and TBHP. Copyright © 2016 John Wiley & Sons, Ltd.     

Formation of aldehydes and ketones via reduction of alkyl monohalides by electrogenerated nickel(I) salen in dimethylformamide in the presence of water, oxygen, and light

Addition of a stoichiometric amount of a primary alkyl monohalide (1-bromooctane) to a solution of electrogenerated nickel(I) salen in dimethylformamide containing water, followed by irradiation with a xenon arc lamp and brief exposure to air, results in the formation of an aldehyde (1-octanal). Analogous experiments with a secondary alkyl monohalide (2-bromohexane) afford a ketone. Other products are alkanes, alkenes, and dimers that arise from classic radical coupling and disproportionation of alkyl radicals.