The invention relates to a method for preparing symmetrical ketazines of the formula ##EQU1## and unsymmetrical ketazines of the formula ##EQU2## and mixtures of ketazines (I), (II) and (IV) and (I), (III) and (V) wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical or cycloalkyl radical of from 3 to 12 carbon atoms, or a phenyl radical, the aforesaid radicals being unsubstituted or substituted with radicals which are stable in the medium in which the ketazines are prepared; and in which case R.sup.1 and R.sup.2 can be the same or different radicals, and R.sup.3 and R.sup.4 are radicals different from each other and are each a radical different from R.sup.1 and R.sup.2 ; or R.sup.1 and R.sup.2, or R.sup.1 and R.sup.3, or R.sup.3 and R.sup.4 of either or both the ##EQU3## moieties together form a cyclic or substituted cyclic radical of from 3 to 11 carbon atoms in the ring, which comprises:A. oxidizing a secondary alcohol of the formula ##EQU4## alone or together with a different secondary alcohol of the formula ##EQU5## or ##EQU6## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each has the same meaning as defined above, the oxidation to be carried out in the liquid phase employing molecular oxygen or a gaseous mixture containing the same, at a temperature and pressure which is sufficient to maintain the alcohol or alcohols in the liquid phase and result in a liquid phase mixture containing the peroxidic products of the auto-oxidation of the alcohol (VI) or the alcohols (VI) and (VII) or (VI) and (VIII);b. reacting the peroxidic products with ammonia in the presence of cyanogen or a nitrile R.sup.5 (CN).sub.n (IX) wherein n is an integer of from 1 to 6 and R.sup.5 is an unsubstituted or substituted saturated aliphatic, acyclic, or cyclic radical of from 1 to 12 carbon atoms or a phenyl or pyridinyl radical to result in the ketazine (I) or the mixture of ketazines (I), (II) and (IV) or (I), (III) and (V); andC. recovering the ketazine or mixture of ketazines.