A process for the catalytic oxidative dehydrogenation of one or more C 2-4 alkanes comprising n pre-reactors for the oxidative dehydrogenation of said alkanes in the presence of a mixed metal oxide oxidative dehydrogenation catalyst system which complexes reactive oxygen in the catalyst system, where n is an integer of 2 or more, and one or more downstream main oxidative reactors comprising: i) passing a feed stream comprising said one or more C 2-4 alkanes through one or more of n-1 pre-reactors at a temperature from 300°C to 500°C and a pressure from 3.447 kPag to 689.47 kPag (0.5 to 100 psig) to oxidatively dehydrogenate at least a portion of the feedstream until the oxidative dehydrogenation catalyst is depleted of reactive oxygen; ii) diverting the feed stream from the pre-reactor in which the oxidative dehydrogenation catalyst is depleted of reactive oxygen to a pre-reactor in which the oxidative dehydrogenation catalyst is substantially saturated with reactive oxygen; iii) passing the product stream from said n-1 pre-reactor together with additional oxygen feed to one or more downstream main reactors at a temperature from 300°C to 500°C and a pressure from 3.447 kPag to 689.47 kPag (0.5 to 100 psig) for the oxidative dehydrogenation of said one or more C 2-4 alkanes; iv) removing a product stream from said one or more downstream main reactors comprising corresponding C 2-4 alkenes, unreacted C 2-4 alkanes, unreacted oxygen and water [vapor] and passing it through one or more pre-reactors depleted of reactive oxygen at a temperature from 50°C to 270°C and a pressure from 3.447 kPag to 689.47 kPag to complex the oxygen in the product stream and increase the reactive oxygen saturation of the oxidative dehydrogenation catalyst with reactive oxygen and recovering a product stream substantially free of oxygen; v) continuing step iv) until either: a) there is another pre-reactor more depleted of reactive oxygen than that through which the product stream is being passed; or b) the oxidative dehydrogenation catalyst in the pre-reactor is substantially saturated with reactive oxygen; vi) switching the flow of product stream from the formerly reactive oxygen depleted pre-reactor to a more reactive oxygen depleted pre-reactor; and vii) if necessary completely saturating the oxidative dehydrogenation catalyst with reactive oxygen in said formerly reactive oxygen depleted pre-reactor; and viii) bringing on line the formerly reactive oxygen depleted pre-reactor. i) passing a feed stream comprising said one or more C 2-4 alkanes through one or more of n-1 pre-reactors at a temperature from 300°C to 500°C and a pressure from 3.447 kPag to 689.47 kPag (0.5 to 100 psig) to oxidatively dehydrogenate at least a portion of the feedstream until the oxidative dehydrogenation catalyst is depleted of reactive oxygen; ii) diverting the feed stream from the pre-reactor in which the oxidative dehydrogenation catalyst is depleted of reactive oxygen to a pre-reactor in which the oxidative dehydrogenation catalyst is substantially saturated with reactive oxygen; iii) passing the product stream from said n-1 pre-reactor together with additional oxygen feed to one or more downstream main reactors at a temperature from 300°C to 500°C and a pressure from 3.447 kPag to 689.47 kPag (0.5 to 100 psig) for the oxidative dehydrogenation of said one or more C 2-4 alkanes; iv) removing a product stream from said one or more downstream main reactors comprising corresponding C 2-4 alkenes, unreacted C 2-4 alkanes, unreacted oxygen and water [vapor] and passing it through one or more pre-reactors depleted of reactive oxygen at a temperature from 50°C to 270°C and a pressure from 3.447 kPag to 689.47 kPag to complex the oxygen in the product stream and increase the reactive oxygen saturation of the oxidative dehydrogenation catalyst with reactive oxygen and recovering a product stream substantially free of oxygen; v) continuing step iv) until either: a) there is another pre-reactor more depleted of reactive oxygen than that through which the product stream is being passed; or b) the oxidative dehydrogenation catalyst in the pre-reactor is substantially saturated with reactive oxygen; a) there is another pre-reactor more depleted of reactive oxygen than that through which the product stream is being passed; or b) the oxidative dehydrogenation catalyst in the pre-reactor is substantially saturated with reactive oxygen; vi) switching the flow of product stream from the formerly reactive oxygen depleted pre-reactor to a more reactive oxygen depleted pre-reactor; and vii) if necessary completely saturating the oxidative dehydrogenation catalyst with reactive oxygen in said formerly reactive oxygen depleted pre-reactor; and viii) bringing on line the formerly reactive oxygen depleted pre-reactor.