Hydrogenation of fatty acid esters. III: Hydrogenation of methyl (9Z,12Z)-octadecadienoate and methyl (9Z,12Z,15Z)-octadecatrienoate

The title hydrogenation catalyzed by nickel(II) 2,4-pentanedionate-triethylaluminium system has been studied with the use of combination of initial rate measurements with time changes of product distribution. It was found that the hydrogenation of methyl (9 Z ,12 Z )-octadecadienoate is first order in the octadecadienoate. Similar results were obtained also for (9 Z ,12 Z ,15 Z )-octadecatrienoate. The course of both reactions has been described by models involving set of parallel and consecutive hydrogenation steps and reversible isomerizations. Computed rate constants for hydrogenation of methyl (9 Z ,12 Z )-octadecadienoate support qualitative conclusions deduced from the product analysis.