Engineering aspects of industrial liquid-phase air oxidation of hydrocarbons

Liquid-phase air oxidation of hydrocarbons, notably p-xylene, cumene, ethyl benzene/isobutane, cyclohexane, and n-butane, is of great scientific, techn ological, and commercial importance. This state-of-the-art paper covers the chemistry and engineering science aspects of these reactions. The role of uncatalyzed reactions and metal ion and mixed metal ion catalysts with brom ide activation is discussed. An analysis is presented for the role of mass transfer ill influencing the rate of reaction and selectivity for the desir ed product. Different types of reactors that are used, notably bubble-colum n reactors and mechanically agitated reactors, are analyzed, and a simple b asis is provided for selection of reactors. Some emerging oxidation systems , notably oxidation of cycloalkenes ( cyclohexene/cyclooctene/cyclododecene ) and oxidation of isobutane under supercritical conditions, are presented. New strategies for conducting air oxidations, such as in biphasic systems (including fluorous biphasic systems), biocatalysis, photocatalysis, etc., are emerging and illustrate the considerable tailoring of the reaction micr oenvironment that is becoming possible. In some cases, it may be possible t o manipulate chemo-, regio-, and enantioselectivity in these reactions.