Double bond oxidative cleavage of monoenic fatty chains

A two steps process for the production of azelaic acid and pelargonic acid or alternatively of omega-hydroxynonanoic and pelargonic acid, starting from respectively oleic acid and oleyl alcohol has been studied. In the first step, the monoenic reagent reacts with hydrogen peroxide, in the presence of pertungstic acid, as catalyst, to give the corresponding diol (hydroxylation of the double bond). In the second step, the reaction mixture obtained in the first step containing the formed diol and the exhausted catalyst. was additioned of cobalt acetate and reacted with molecular oxygen (oxidative cleavage of vicinal diols). As the first step has largely been studied in the literature, the study of the nature of the catalytic site and of the catalytic mechanism of the second step of the process is the main subject of this work with the objective of identifying, for this step, an independent and reusable catalyst. In particular, we focused our attention on the diol deriving from oleyl alcohol, because reagents and products are more easily separated and analyzed. The study of the mentioned reactions is complicated by the presence of respectively two or three phases in the reactor. The in-situ formed catalyst, active in the second reaction step, seems to be a lacunary poly-oxometalate in which cobalt, sequestered by the tungstate anion groups and accessible to the reagent. is the active component. This has been shown by polarographic analyses of the catalyst solution before and after the reaction. and is also confirmed by the observation that cobalt, sequestered by EDTA, in the absence of tungstic acid is active, too. (C) 2003 Elsevier Science B.V. All rights reserved.