Oxidation, aerobic selective

Copper-Catalysed Aerobic Oxidation of Selected Primary Alcohols... 

Aerobic denitrification—under aerobic but low-oxygen conditions, the nitrite formed can be reduced to nitrous oxide by select chemoautotrophic and heterotrophic nitrifler... 

Aerobic selective oxidation of alkylaromatics, including cumene (CU), ethylbenzene (EtB), and cyclohexylbenzene (CyB), to the corresponding hydroperoxides (CHPs) represents a key step for several large-scale productions, including the Hock process for the synthesis of phenol (see Chapter 2) [15] and the Shell styrene monomer/propylene oxide (SM/PO) process for the production of propylene oxide (PO) and styrene monomer (SM) [16]. 

Figure 2.9 Evidence that surface PdO catalyzes the aerobic selective oxidation of allylic alcohols over Pd/Al20j (a) Strong dependence of TOF on surface oxide concentration and (b) in situ reduction of active PdO phase accompanying onstream deactivation. (Adapted from Refs [96] and [144] by permission of the Royal Society of Chemistry.)...

Long, J. Xie, X. Xu, Gu, Q. Chen, L. Wang, X., Nitrogen-Doped Graphene Nanosheets as Metal-Free Catalysts for Aerobic Selective Oxidation of Benzylic Alcohols. ACS Catalysis 2012,2 (4), 622-631. 

When the aerobic oxidation of a-isophorone is performed in the presence of heteropoly acids or salts thereof in combination with additives such as copper sulfate and/or molybdenum oxides, a selectivity of 61 % was observed at 83% conversion. Molybdovanadophosphates supported on active carbon also mediate the oxidation of a-isophorone, however in most cases oxidation occurs on the methyl group, affording formylisophorone. 

Vinod, C., Wilson, K. and Lee, A. (2011). Recent Advances in the Heterogeneously Catalysed Aerobic Selective Oxidation of Alcohols, J. Chem. Tech. Biot., 86, pp. 161-171. 

Parlett CMA, KeshwaUa P, Wainwright SG, et al. Hierarchically ordered nanoporous Pd/SBA-15 catalyst for the aerobic selective oxidation of stericaUy challenging aUylic alcohols. /ICS Catal. 2013 3 2122-2129. 

Vinod CP, Wilson K, Lee AF. Recent advances in the heterogeneously catalysed aerobic selective oxidation of alcohols. J Chem Technol Biotechnol. 2011 86 161-171. 

There are several available terminal oxidants for the transition metal-catalyzed epoxidation of olefins (Table 6.1). Typical oxidants compatible with most metal-based epoxidation systems are various alkyl hydroperoxides, hypochlorite, or iodo-sylbenzene. A problem associated with these oxidants is their low active oxygen content (Table 6.1), while there are further drawbacks with these oxidants from the point of view of the nature of the waste produced. Thus, from an environmental and economical perspective, molecular oxygen should be the preferred oxidant, because of its high active oxygen content and since no waste (or only water) is formed as a byproduct. One of the major limitations of the use of molecular oxygen as terminal oxidant for the formation of epoxides, however, is the poor product selectivity obtained in these processes [6]. Aerobic oxidations are often difficult to control and can sometimes result in combustion or in substrate overoxidation. In... 

Bio-ethanol is attracting growing interests in relation to the shift of raw materials from petroleum to biomass. A pioneering work by Christensen is that over MgAl203 support gold is much more selective to acetic acid than palladium and platinum in the aerobic oxidation of ethanol in water in a batch reactor. Figure 32 shows that selectivity to acetic acid exceeds 80% [99]. In contrast, Au/Si02 catalysts prepared by deposition reduction... 

Recently, great advancement has been made in the use of air and oxygen as the oxidant for the oxidation of alcohols in aqueous media. Both transition-metal catalysts and organocatalysts have been developed. Complexes of various transition-metals such as cobalt,31 copper [Cu(I) and Cu(II)],32 Fe(III),33 Co/Mn/Br-system,34 Ru(III and IV),35 and V0P04 2H20,36 have been used to catalyze aerobic oxidations of alcohols. Cu(I) complex-based catalytic aerobic oxidations provide a model of copper(I)-containing oxidase in nature.37 Palladium complexes such as water-soluble Pd-bathophenanthroline are selective catalysts for aerobic oxidation of a wide range of alcohols to aldehydes, ketones, and carboxylic acids in a biphasic... 

Aerobic oxidation of formaldehyde in water under mild conditions (20-40 °C, 1 atm of air or 02) in the presence of Ce-substituted POMs affords formic acid with high selectivity. 

Figure 1.16 Schematic and comparative illustrative of grafting (a) an amorphous silica gel and (b) an ordered MCM-41 silica materials. Entrapment of oxidation catalyst perruthenate inside the channels of MCM-41 silica (below) results in a shape-selective aerobic catalyst, which may not be desirable from the viewpoint of catalyst versatality (Reproduced from ref. 39, with permission.)...

Nakajima et al. (128) found that a number of diamines functioned as moderately effective ligands for Cu(II) in the catalytic aerobic oxidation of 2-naphthols. A series of proline derivatives were evaluated with the aniline ligand 187 providing optimal selectivities. Unfortunately, 2-naphthol affords only racemic binaphthol. With an isolated catalyst, formulated as 187 Cu(OH)Cl in analogy to the known TMEDA Cu(OH)Cl (TMEDA = A,A,A,A-tetramethylethylenediamine), oxidative... 

Bolm et al. (130) reported the asymmetric Baeyer-Villiger reaction catalyzed by Cu(II) complexes. Aerobic oxidation of racemic cyclic ketones in the presence of pivalaldehyde effects a kinetic resolution to afford lactones in moderate enan-tioselectivity. Aryloxide oxazolines are the most effective ligands among those examined. Sterically demanding substituents ortho to the phenoxide are necessary for high yields. Several neutral bis(oxazolines) provide poor selectivities and yields in this reaction. Cycloheptanones and cyclohexanones lacking an aryl group on the a carbon do not react under these conditions. 

Many wastewater flows in industry can not be treated by standard aerobic or anaerobic treatment methods due to the presence of relatively low concentration of toxic pollutants. Ozone can be used as a pretreatment step for the selective oxidation of these toxic pollutants. Due to the high costs of ozone it is important to minimise the loss of ozone due to reaction of ozone with non-toxic easily biodegradable compounds, ozone decay and discharge of ozone with the effluent from the ozone reactor. By means of a mathematical model, set up for a plug flow reactor and a continuos flow stirred tank reactor, it is possible to calculate more quantitatively the efficiency of the ozone use, independent of reaction kinetics, mass transfer rates of ozone and reactor type. The model predicts that the oxidation process is most efficiently realised by application of a plug flow reactor instead of a continuous flow stirred tank reactor. 

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