Patent ID: 7247753

Claim:
A process for the preparation of macrocyclic ketones of the formula I where X is a mono- or polyunsaturated or saturated C 10 –C 17 -alkyl radical which may optionally be substituted by a C 1 –C 6 -alkyl radical, said process comprising direct cyclization of a compound of the formula II where R 1 , R 2 , in each case independently of the other, may be identical or different and are hydrogen or C 1 –C 6 -alkyl and X has the meaning given above, and wherein said cyclization takes place in the gas phase over a heterogeneous catalysts comprising, as active components, oxides, hydroxides or carboxylates of subgroups I to VIII, or of main groups II, III and IV, wherein the compound of formula (II) is evaporated and then passed at a desired reaction temperature in gaseous form over the catalyst arranged in a fixed bed.