Cydohexane Conversion

BASF. In the Badische process, cyclohexanone is produced by liquid-phase catalytic air oxidation of cyclohexane to KA oil, which is a mixture of cyclohexanone and cydohexanol, and is followed by vapor-phase catalytic dehydrogenation of the cydohexanol in the mixture. Overall yidds range from 75% at 10% cydohexane conversion to 80% at 5% cydohexane conversion. 

In patents issued by Redox Technologies, oxidation is reported to occur more efficiently if high concentrations of cydohexane are used (AcOH/cydohexane weight ratio between 50 50 and 15 85, instead of80 20), and if the conversion ofthe reactant is kept below 30%, instead of more than 70% [19]. A low concentration of catalyst is recommended. An 88% AA selectivity at 21% cydohexane conversion is obtained in an acetic add solvent with a Co(OAc)2 catalyst (cydohexane/Co ratio higher than 150),... 

In Amoco patents [18b], the addition of controlled amounts of water after the initiation ofthe oxidation reaction is claimed to be a tool to obtain a better yield to AA. The best yield achieved was 88% (based on the identifiable compounds) at 98% cyclohexane conversion, with a Co(II) acetate catalyst, an acetic add solvent, at 95 °C and 70 atm air pressure. It is reported that water, if present during the induction period, depletes the concentration of free radicals in the absence of water, the yield was remarkably lower. These results are comparable to those attained by the air /nitric acid two-step oxidation of cydohexane. 

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