Oxygen separation oxidation

Store separately from oxygen and oxidants, using a fire-resistant partition where neeessary. 

The noncatalytic oxidation of propane in the vapor phase is nonselec-tive and produces a mixture of oxygenated products. Oxidation at temperatures below 400°C produces a mixture of aldehydes (acetaldehyde and formaldehyde) and alcohols (methyl and ethyl alcohols). At higher temperatures, propylene and ethylene are obtained in addition to hydrogen peroxide. Due to the nonselectivity of this reaction, separation of the products is complex, and the process is not industrially attractive. 

Double Substitution In such processes, two substitutions take place simultaneously. For example, in perovskite oxides, La may be replaced by Sr at the same time as Co is replaced by Fe to give solid solutions Lai Sr Coi yFey03 5. These materials exhibit mixed ionic and electronic conduction at high temperatures and have been used in a number of applications, including solid oxide fuel cells and oxygen separation. 

Electropox [Electrochemical partial oxidation] Also called Pox. An electrochemical process for oxidizing methane to syngas. It combines the partial oxidation and steam reforming of methane with oxygen separation in a single stage. Invented in 1988 by T. J. Mazanec at BP Chemicals. An industrial-academic consortium to develop the process was formed in 1997. 

There has been considerable interest in Ce02 as a component of solid oxide fuel cells, especially as an anode material, and also for use in oxygen separation membranes. The material shows a wide nonstoichiometry range, with oxygen vacancies as the... 

Smith and Chalk [49] achieved a complete separation of oxygen, nitric oxide, nitrous oxide and carbon dioxide on a column packed with a molecular sieve of 5 A (100-120 mesh), programmed between 35 °C and 250 °C at 39 °C/m. 

We have studied the proton and oxide anion transport, conduction, and permeation in metals, dense oxide ceramics and, also briefly, in polymers (see also Chapters 2,5, and 8). This section describes the application of proton and oxide permeation in these materials in hydrogen and oxygen separations. 

Lubrication. Lubricants separate the solid surfaces, either so completely that the projections on the two surfaces cannot touch, or they provide sufficient covering on the surfaces, so that if any projections do really touch the other surface the intensity of seizure is much less than if the metals were clean. We have already seen that adsorbed films of oxygen, or oxide films, reduce the friction far below that of chemically clean metal surfaces in a sense, therefore, such films might be considered lubricants. But the practical problem of lubrication consists in reducing the friction between ordinary metal surfaces, with their surface films, to the lowest practicable value. 

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