Synthesis of cyclic acetals (ketals) from oleochemicals using a solvent free method

Abstract

The reaction selectivities of acid catalyzed ring opening reactions of epoxidized methyl oleate (methyl 9,10-epoxy stearate; EMO), to form either ketal (acetal) or branched ester products have been studied. We have produced methyl 9-(2-butyl-2-methyl-5-octyl-1,3-dioxolan-4-yl) nonanoate (hexanone methyl stearate acetal, HMSA), an oleochemically based ketal (acetal), in 83% isolated yield; from epoxidized methyl oleate and 2-hexanone. Utilizing our reaction chemistry, we have also been able to demonstrate the relative selectivities, in competitive experiments, by reacting EMO with 2-pentanone and octanoic acid. Finally, by controlling temperature and acid concentration, we were able to control the product distribution of the reaction of EMO with the bi-functional levulinic acid. Either the ketal (acetal), or the branched ester product could be favored. This research may help lead to the formation of new hydrophobic molecules for the synthesis of new surfactants from oleochemicals.