A process for the formation of a catalyst of predetermined pore size distribution and pore volume from an alumina hydrogel formed and obtained by precipitation from a solution containing a hydrous form of alumina in 1-5 wt. % concentration and an anion that is soluble in an alkaline solution and forms an aluminum salt, at pH 8-12, and temperature ranging about 15.degree. F.-120.degree. F., and then extended by contact with a solution of a water-soluble polymer containing 2 to about 24 monomer units from the group consisting of (a) polyethylene glycols, (b) polypropylene glycols, and (c) polyethylene amines sufficient to absorb the polymer and displace water from the pores until the weight ratio of polymer:alumina ranges about 0.5:1 to about 4:1. A metal hydrogenation component, or components, suitably a Group VI-B or Group VIII metal, or both, can be added during the polymer extending step, if desired, by adding a soluble compound, or salt of the desired metal, or metals, to the polymer containing solution. In either event, the polymer is removed by solvent extraction, dried and calcined to form gamma alumina.