Oxygen, molecular hydrocarbon oxidation processes

Petrox A general term for processes that enhance the yield of organic oxidation processes (e.g., butane to maleic anhydride, propylene to acrylonitrile) by the use of oxygen instead of air. Selectivity is improved at the expense of conversion, and the feedstock hydrocarbon is recycled by use of a special molecular sieve. Developed by BOC Gases. The Petrox system for acrylonitrile was developed in association with Mitsubishi Chemical. 

This chapter highlights the ruthenium-catalyzed dehydrogenative oxidation and oxygenation reactions. Dehydrogenative oxidation is especially useful for the oxidation of alcohols, and a variety of products such as ketones, aldehydes, and esters can be obtained. Oxygenation with oxo-ruthenium species derived from ruthenium and peroxides or molecular oxygen has resulted in the discovery of new types of biomi-metic catalytic oxidation reactions of amines, amides, y3-lactams, alcohols, phenols, and even nonactivated hydrocarbons tmder extremely mild conditions. These catalytic oxidations are both practical and useful, and ruthenium-catalyzed oxidations will clearly provide a variety of futrue processes. 

Molecular oxygen can also oxidize a variety of organic compounds, including hydrocarbons, aldehydes, amines, ethers and ketones. These autooxidation reactions can be used to make a variety of small molecules and a number of industrial processes rely on the controlled oxidation of organics using molecular oxygen (often with a metal catalyst). Examples include the formation of phenol and acetone from cumene (isopropylbenzene) and cyclohexanone from cyclohexane. Phenol is a popular starting material for a number... 

Molecular oxygen is the major cause of irreversible deterioration of hydrocarbon substrates, leading to the loss of useful properties and to the ultimate failure of the substrate. The oxidation process of hydrocarbons is autocatalytic oxidation starts slowly, sometimes with a short induction period, followed by a gradual increase in the rate, concomitant with the build up of hydroperoxides, which eventually subside, giving rise to a sigmoidal oxidation curve. When initiators such as peroxides are present, the length of the induction period is absent, or very short, but it can be prolonged by antioxidants, as shown in Fig. 1. The basic autoxidation theory of hydrocarbons involves a complex set of elementary reaction steps in a free radical-initiated chain reaction mechanism the basic tenets of this theory apply equally to polymer oxidation. 

Oxygen is one of the most interesting elements playing a fundamental role in catalysis, because on the one hand it is a component of the most widely used type of catalysts - oxides, and on the other hand it is the reactant in one of the most important types of catalytic reactions - oxidation. The attack of oxygen on the hydrocarbon molecular is the easiest route to functionalize this molecule, and selective oxidation processes, in which hydrocarbon molecules are oxygenated to form alcohols, aldehydes or acids are the basis of the modern petrochemical... 

O2). The major purpose of the plasma-chemical phase is the complete conversion of NO to NO2 with simultaneous partial destruction of hydrocarbons. The oxidation process starts in the plasma with dissociation of molecular oxygen (O2) and generation of atomic oxygen through electronic excitation and dissociative attachment ... 

The initial steps in oxidative reaction of aromatic, poly-aromatic and other cyclic and linear unsaturated hydrocarbons in the atmosphere or in combustion involve radical formation. These radicals react with molecular oxygen. The subsequent reactions of these peroxy radicals, as shown e.g. in Figure 4.1, result in unsaturated linear or cyclic, oxygenated or multi-oxygenated hydrocarbon intermediates. The thermochemistry for these unsaturated - oxygenated species is needed to evaluate their stability and likely reaction paths in the environment, in combustion and in other thermal and oxidative processes. 

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