Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons are treated with a dehydrogenation catalyst comprising a modified iron catalyst in the presence of steam in a multicatalyst bed system. The reaction mixture containing unconverted hydrocarbons, dehydrogenated hydrocarbons, hydrogen and steam is then contacted with an oxidation catalyst whereby hydrogen is selectively oxidized. The selective oxidation catalyst which is used will comprise a noble metal of Group VIII of the Periodic Table, a metal of Group IVA and, if so desired, a metal of Group IA or IIA composited on a porous inorganic support. The inorganic support will comprise an alumina precursor which possesses and ABD less than about 0.6 g/cc, a pore volume greater than about 0.5 cc/g, and a pore distribution such that between 10% and 70% of the pore volume is present as pores whose diameters are greater than about 300 Angstroms. After peptizing and calcination at a temperature of about 900.degree. to about 1500.degree. C., the resulting alumina will possess an ABD in the range of from about 0.3 to about 1.1 g/cm, a pore volume greater than about 0.2 cc/g, a pore distribution such that more than 40% of the pore volume is present in pores greater than 1500 Angstroms, a piece density in the range of from about 0.3 to about 2.0 g/cc, and a particle size which possesses a diameter of at least 2 mm.