The effect of catalyst nature, temperature, acidity, promoters, and feedstock composition on dodecene-1 carbonylation in the presence of Pd compounds in an ionic liquid medium yielding higher fatty acid and their esters was studied. Palladium salts without phosphine ligands show high activity in tetrabutylammonium bromide. In systems of this kind, the catalyst is suspended in the reaction mass in the form of Pd particles with a size of 4-10 nm. It was shown that the catalytic system can be repeatedly used without loss of activity. It is acceptable to use synthesis gas instead of bare carbon monoxide with the selectivity for tride-canoic acid increasing.