Catalytic oxidation, hydrocarbons

Bordes E. (1987a). Crystallochemistry of V-P-O phases and application to catalysis, Catal. Today, 1, 499-526 Bordes E. (1987b). Reactivity and crystal chemistry of V-P-O phases related to C4 -hydrocarbon catalytic oxidation, Catal. Today, 3, pp. 163-174. 

Bordes, E. Reactivity and crystal chemistry of V-P-O phases related to C4-hydrocarbon catalytic oxidation. Catal. Today 1987, 3, 163-174. 

Commercial production of acetic acid has been revolutionized in the decade 1978—1988. Butane—naphtha Hquid-phase catalytic oxidation has declined precipitously as methanol [67-56-1] or methyl acetate [79-20-9] carbonylation has become the technology of choice in the world market. By-product acetic acid recovery in other hydrocarbon oxidations, eg, in xylene oxidation to terephthaUc acid and propylene conversion to acryflc acid, has also grown. Production from synthesis gas is increasing and the development of alternative raw materials is under serious consideration following widespread dislocations in the cost of raw material (see Chemurgy). 

Direct oxidation of hydrocarbons and catalytic oxidation of isopropyl alcohol have also been used for commercial production of acetone. 

Liquid-Phase Oxidation. Liquid-phase catalytic oxidation of / -butane is a minor production route for acetic acid manufacture. Formic acid (qv) also is produced commercially by Hquid-phase oxidation of / -butane (18) (see HYDROCARBON OXIDATION). 

Catalytic Oxidation for Straight-Chain Paraffinic Hydrocarbons. Synthetic fatty acids (SFA) are produced by Eastern European countries, Russia, and China using a manganese-catalyzed oxidation of selected paraffinic streams. The technology is based on German developments that were in use during World War II. The production volume in 1984 was estimated to be about 5.5 x ICf t/yr. The oxidation is highly exothermic and is carried out at about 105—125°C, mostly in continuous equipment. 

Although ethylene is produced by various methods as follows, only a few are commercially proven thermal cracking of hydrocarbons, catalytic pyrolysis, membrane dehydrogenation of ethane, oxydehydrogenation of ethane, oxidative coupling of methane, methanol to ethylene, dehydration of ethanol, ethylene from coal, disproportionation of propylene, and ethylene as a by-product. 

M. A. Pala22olo, and C. L. Jamgonhian "Destmction of Chlorinated Hydrocarbons by Catalytic oxidation," U.S. Environmental Protection Agency, Report EPA/600/82-86/079, Research Triangle Park, N.C., Jan. 1987. 

Further oxidation of the pollutants outside the combustion chamber. This oxidation may be either by normal combustion or by catalytic oxidation. These systems require the addition of air into the exhaust manifold at a point downstream from the exhaust valve. An air pump is employed to provide this air. Figure 31-2 illustrates an engine with an air pump and distribution manifold for the oxidation of CO and hydrocarbons (HC) outside the engine. 

High levels of sulfur not only form dangerous oxides, but they also tend to poison the catalyst in the catalytic converter. As it flows over the catalyst in the exliaust system, the sulfur decreases conversion efficiency and limits the catalyst s oxygen storage capacity. With the converter working at less than maximum efficiency, the exhaust entering the atmosphere contains increased concentrations, not only of the sulfur oxides but also, of hydrocarbons, nitrogen oxides, carbon monoxides, toxic metals, and particulate matter. 

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

Fumaric acid is used in the plastics industry, in the food industry and as a source of malic add. Although demand has increased rapidly over the last 30 years its production from fermentation has been totally replaced by a chemical method. It is now produced far more cheaply by the catalytic oxidation of hydrocarbons, particularly benzene. With the continuing uncertainties concerning the availability and cost of petroleum, however, fermentation may yet be a viable alternative. 

Hydrogen cyanide reactions catalysts, 6,296 Hydrogen ligands, 2, 689-711 Hydrogenolysis platinum hydride complexes synthesis, 5, 359 Hydrogen peroxide catalytic oxidation, 6, 332, 334 hydrocarbon oxidation iron catalysts, 6, 379 reduction... 

Attempts to achieve selective oxidations of hydrocarbons or other compounds when the desired site of attack is remote from an activating functional group are faced with several difficulties. With powerful transition-metal oxidants, the initial oxidation products are almost always more susceptible to oxidation than the starting material. When a hydrocarbon is oxidized, it is likely to be oxidized to a carboxylic acid, with chain cleavage by successive oxidation of alcohol and carbonyl intermediates. There are a few circumstances under which oxidations of hydrocarbons can be synthetically useful processes. One group involves catalytic industrial processes. Much effort has been expended on the development of selective catalytic oxidation processes and several have economic importance. We focus on several reactions that are used on a laboratory scale. 

What can all these studies suggest to the inorganic chemist interested in the controlled and fAcile catalytic oxidation of hydrocarbons Groves and coworkers have already shown that iron porphyrins in the presence of iodosylbenzene and peracids can be used for such catalytic reactions (37, 38). However, the cost of the oxidants makes such reaction uneconomical at this time. 

The only difference between the active oxidizing and a ferric porphyrin hydroxide complex is two electrons (scheme 4). Indeed, the electrochemical oxidation of hydroxy ferric tetra-mesitylporphyrin shows two reversible one-electron oxidations (40), and, in principle, use of water and an electrode should allow development of a system capable of catalytically oxidizing hydrocarbons. 

Still higher oxidation rates are achieved when hydrocarbons are oxidized in the presence of the catalytic system including the Co, Mn, and Br- ions. The Mn-Br binary system is less... 

MERICAT A process for removing mercaptans from petroleum fractions by a combination of catalytic oxidation and extraction with aqueous sodium hydroxide, using a proprietary contactor based on a bundle of hollow fibers. The sulfur products are disulfides, which remain in the hydrocarbon product. Developed by the Merichem Company, Houston, TX, and used in 61 plants as of 1991. Mericat II is a variation which includes a carbon bed too there were four installations as of 1991. See also Thiolex. 

REGEN A process for removing mercaptans from hydrocarbon fractions by catalytic oxidation and extraction with aqueous alkali, using a bundle of hollow fibers. Developed by the Merichem Company, Houston, TX, and used in 34 plants as of 1991. 

It is diagnostic of electronic/chemical state, is sensitive to point defects, and can be used to probe the distribution of promoters in catalytic oxides (67). Examples include effects of the distribution of antimony in Sb-Sn02 catalysts (used for selective hydrocarbon oxidation) on the electronic structure of the catalyst and mapping of point defects in titania catalysts. 

A mechanism for the catalytic oxidation of hydrocarbons is due to Mars Van Krevelen (Spec Suppl Chem Eng Sci 3 41, 19541. These assumptions are made ... 

The chemical problem here involves the photochemical and catalytic oxidation of S02 and its mixtures with the hydrocarbons and NO however the primary concern is the photochemical reactions, both gas-phase and aerosol-forming. 

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