Gas phase oxygen oxidation of alkylaromatics over CVD Fe/Mo/borosilicate molecular sieve, Fe/Mo/DBH VII. Oxidative dehydrogenation of alkylaromatics Original Research Article

Over the chemical vapor deposited (CVD) Fe/Mo/DBH catalyst, alkylaromatics such as ethylbenzene, p-diethylbenzene, p-ethyltoluene and p-(t-butyl)ethylbenzene were dehydrogenated to the corresponding alkenylaromatics by O2 gas phase oxidation with or without CO2. The resulting alkenyl group was further oxidized to oxygenates such as aldehyde, ketone and carboxylic acid by secondary oxidation. Carbon dioxide promoted hydrogen abstraction from the alkylaromatic substrates, but it adversely affected oxidation of the resulting alkenyl group to oxygenates in the secondary reaction. The para-selective nature of the catalyst defined reactivities of these substrates for the oxidative dehydrogenation reaction.