SO 2 /O 2 dehydrogenation of ethylbenzene

In the SO 2 dehydrogenation of ethylbenzene to styrene using alkalized alumina or titania catalysts, addition of small amounts of oxygen results in (1) higher styrene yields at equivalent SO 2 concentrations, or (2) equivalent styrene yields with lower SO 2 requirements. By staging the oxygen additions, styrene yields of greater than 80% are achieved at SO 2 levels as low as 0.15 mole/mole ethylbenzene when 0.45 mole O 2 is added in increments of 0.15 mole. The low SO 2 concentration and staging of the oxygen result in a high selectivity (94%) for the reaction to styrene by minimizing both byproduct formation and combustion.