Decarbonylation dehydration of fatty acids to alkenes in the presence of transition metal complexes

The catalytic decarbonylation of stearic acid into a mixture of heptadecenes has been accomplished by use of a catalyst system comprised of rhodium trichloride (RhCl3) and triphenylphosphine. The isomeric composition of the heptadecenes formed was found, by spectroscopic and chemical methods, to be dependent upon the type of rhodium catalyst employed. Anhydrous RhCl3 produced about the same amount of 2‐heptadecene, twice the amount of 3‐heptadecene, and about half the amount of 1‐heptadecene as hydrated RhCl3. The active catalytic species formed in situ has been identified as the rhodium I complex [(C6H5)3P]2Rh(CO)Cl. A mechanistic pathway to account for the observed decarbonylation products employing the above catalyst is presented.