Abstract: The invention relates to a process for the preparation of cycloalkanone and optionally cycloalkanol by causing a mixture containing cycloalkylhydroperoxide to react with cycloalkene under the influence of a catalyst, characterised in that the reaction is carried out with a short measure of cycloalkene relative to the cycloalkylhydroperoxide, under such conditions that virtually all of the cycloalkene reacts to cycloalkene oxide and optionally cycloalkanol and/or cycloalkanone, after which the mixture, optionally after decomposition of cycloalkylhydroperoxide and distillation of cycloalkane, is subjected to a first separation, in which cycloalkene oxide--and optionally other components--is separated, after which the cycloalkene oxide in the separated mixture is isomerised to substantially cycloalkanone, after which the cycloalkanone obtained--and optionally cycloalkanol--is recovered.

Abstract: An improved method for the preparation of melamine by the conversion of urea and/or thermal decomposition products thereof. The urea and/or thermal decomposition products are converted to melamine in the presence of a gas mixture containing ammonia and carbon dioxide in a reaction zone containing a fluidized bed of catalytically active material. Melamine is desublimated from the melamine containing gas mixture in a desublimation zone by a dry-capture method leaving a desublimator off-gas mixture of ammonia, carbon dioxide and gaseous impurities. A major portion of this desublimator off-gas mixture is compressed and recirculated to the reaction zone as fluidizing gas for the bed of catalytically active material, without intervening treatment to remove gaseous impurities from the desublimator off-gas.