Oxygen compounds structural properties

By virtue of the oxophilicity of aluminium, many compounds exist in which at least one of the metal s formal valencies is occupied by oxygen or, alternatively, where the coordination state of the metal is raised to 4, 5 or 6 by the donation of electron density from oxygen. This review presents aluminium oxides first and thereafter aluminium hydroxides and organooxides. Although the discussion concentrates on the sohd-state structural properties of such systems, solution structural, theoretical and reactivity studies are also presented. 

Ethers are organic compounds structurally related to alcohols. The oxygen atom in an ether group, however, is bonded not to a carbon and a hydrogen but rather to two carbons. As we see in Figure 12.14, ethanol and dimethyl ether have the same chemical formula, C2H(50, but their physical properties are vastly different. Whereas ethanol is a liquid at room temperature (boiling point 78°C) and mixes quite well with water, dimethyl ether is a gas at room temperature (boiling point —25°C) and is much less soluble in water. 

Although crude petroleum contains small amounts of oxygen, nitrogen, and sulfur, its major constituents are hydrocarbons—compounds of carbon and hydrogen. Isolating individual hydrocarbon substances from petroleum mixtures is an industrial process of central importance. Moreover, it provides a fascinating story that illustrates how the structures of molecules determines the properties of substances and the behavior of those substances in particular processes. The next three sections present a brief introduction to this story, emphasizing the structure-property correlations. 

The availability of surface arrays of active centres able to cooperate in such a way as to avoid the desorption of olefin intermediates, and to allow the rapid transformation of the latter to the final oxygenated compounds. This is a property of the vanadyl pyrophosphate and of heteropolycompounds for these compounds the "intrinsic multifunctionality" arises from the molecular-type organization of the structure into well-defined moieties, each one characterized by specific properties. 

Sources Properties of Hydrocarbons of High Molecular Weight, Research Project 42, 1940-1966, American Petroleum Institute, New York J. Denis, The Relationship Between Structure and Rheological Properties of Hydrocarbons and Oxygenated Compounds Uses as Base Stocks, Journal of Synthetic Lubricants, vol. 1(1—3) 201—238 (1984) J. W. Nederbragt and J. W. M. Boelhouwer, Viscosity Data and Relations of Normal and Iso-Paraffins, Physica Xlll(6-7) 305-318 (1947) R. T. Sanderson, Viscosity-Temperature Characteristics of Hydrocarbons, Industrial Engineering Chemistry 41(2) 368-374 (1949). With permission. 

Source J. Denis, The Relationship Between Structure and Rheological Properties of Hydrocarbons and Oxygenated Compounds Used as Base Stocks, Journal of Synthetic Lubricants, vol. 1(1—3) 201—238 (19S4). With permission. 

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