| abstract |
The present invention relates to a process for the manufacture of a mixture of ketones of the formula I and II, wherein R1, R2, R3 and R4 are independently from each other C1-30-alkyl, by reacting an alkynediol of the formula III in the presence of a catalyst at a temperature of at least 500C and/or at a pressure of at most atmospheric pressure. In preferred embodiments of the invention the ketones of the formulae I and II are identical. Preferably the catalyst is a basic catalyst, most preferably selected from the group consisting of aqueous NaOH and aqueous KOH solutions, and KF on alu minium oxide. The alkynediol is most preferably selected from the group consisting of 2,6,9,13- tetramethyl-tetradeca-2, 12-dien-7-yne-6,9-diol, 2,6, 10, 13 , 17,21 -hexamethyl-docos- 11-yne-10,13-diol, 2,6,10,14,17,21,25,29-octamethyl-triacont-15-yne-14,17-diol, 3,7,10,14-tetramethyl-hexadeca-3,13-dien-8-yne-7,10-diol, 3,6-dimethyl-oct-4-yne-3,6-diol and 2,5-dimethyl-hex-3-yne-2,5-diol. Advantegeously the process of the present invention may be used in the processes for the manufacture of dehydrolinalool or dehydroisophytol to recycle at least one of the starting materials. |