A system and method including an oxidative dehydrogenation (ODH) reactor system, feeding ethane and oxygen to an ODH reactor having ODH catalyst, and dehydrogenating ethane to ethylene via the ODH catalyst in presence of the oxygen in the ODH reactor, thereby forming acetic acid in the ODH reactor. The ODH reactor effluent is discharged through a quench heat exchanger, thereby cooling the effluent via the quench heat exchanger to below a temperature threshold, the effluent including ethylene, acetic acid, water, carbon dioxide, carbon monoxide, and unreacted ethane, wherein residence time of the effluent from the ODH reactor to effluent discharge outlet of the quench heat exchanger is less than a specified upper limit.

A reactor for gas-phase dehydrogenation of a hydrocarbon-comprising stream with an oxygen-comprising stream over a monolithic heterogeneous catalyst. Catalytically active zone(s) comprising monoliths packed next to one another and/or above one another and a mixing zone having fixed internals upstream of each catalytically active zone. Feed line(s) for the hydrocarbon-comprising gas stream to be dehydrogenated at the lower end of the reactor. Independently regulable feed line(s), which supply distributor(s), for the oxygen-comprising gas stream into each of the mixing zones and discharge line(s) for the reaction gas mixture of the autothermal gas-phase dehydrogenation at the upper end of the reactor. The interior wall of the reactor is provided with insulation. The catalytically active zone(s) is accessible from the outside of the reactor via manhole(s). The catalytically active zone(s), mixing zone, independently regulable feed line(s), and distributor(s), may be designed as one component which can individually be mounted and removed.