A process for the preparation of boehmitic alumina compounds having a purity of, at least, 99.95% Al.sub.2 O.sub.3. The compounds produced according to the invention have a pore radii in the range of 3 to 100 nm. The preparation of such compounds is carried out by, first, obtaining an alumina suspension from a neutral aluminum alkoxide hydrolysis and, then, aging the alumina suspension in an autoclave, preferably, at a steam pressure of 1 to 30 bar, corresponding to a temperature of 100.degree. C. to 235.degree. C., for between 0.5 and 20 hours. The aging step of the invention is preferably carried out with stirring at a peripheral speed of 1 to 6 m/s.