Process for preparing saturated branched chain fatty acids

Abstract

A process for preparing saturated branched chain fatty acids or alkyl esters thereof involving subjecting unsaturated fatty acids having 10 to 25 carbon atoms, alkyl esters thereof or mixtures thereof to a skeletal isomerization reaction in the presence of water or a lower alcohol at a temperature of about 240° C. to about 280° C. using a combination of a sterically hindered Lewis base and zeolite as a Brönsted or Lewis acid catalyst, and isolating saturated branched chain fatty acids or alkyl esters thereof or mixtures thereof from the reaction mixture obtained by the skeletal isomerization reaction; wherein the process further comprises (a) recycling said catalyst by washing said catalyst with an acid solution at about 55° C. for about 24 hours, recovering the catalyst followed by heating the catalyst at about 115° C. for about 20 hours for the first four or five cycles of use and (b) in the next subsequent cycle recycling the catalyst by heating the catalyst at about 115° C. for about 20 hours followed by adding Lewis base to the catalyst; steps (a) and (b) can be repeated in subsequent cycles. The yield of said saturated branched chain fatty acids is ≧70 wt %. The sterically hindered Lewis base is a tertiary amine or phosphine with linear or branched C1 to C6 alkyl or phenyl groups attached thereto.