Butadiene is formed by dehydrogenation of butenes which are mixed with steam and oxygen then converted to butadiene by oxidative dehydrogenation over a ferritic oxide catalyst, wherein the sensible heat in the oxidative dehydrogenation reaction product is utilized along with heat produced by thermal oxidation of low value volatile products formed to reduce energy requirements and CO2 emissions. Sensible heat is utilized at high temperature for purposes of superheating feed and at somewhat lower temperatures for purposes of vaporizing feed at sequential locations in the process.