Location: Bio-oils ResearchTitle: Serendipitous production of industrially useful p-cymene by catalytic dehydration and isomerization of perillyl alcohol
Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/18/2022
Publication Date: 5/2/2022
Citation: Moser, B.R., Jackson, M.A., Doll, K.M. 2022. Serendipitous production of industrially useful p-cymene by catalytic dehydration and isomerization of perillyl alcohol [abstract]. American Oil Chemists' Society Annual Meeting and Expo. p. 10.
Technical Abstract: As part of our continuing efforts to produce aliphatic polyesters from fats and oils, we were originally attempting to esterify 9-decenoic acid with perillyl alcohol [(4-isopropenyl-1-cyclohexen-1-yl)methanol] in the presence of catalytic para-toluenesulfonic acid in refluxing toluene to give tris-unsaturated perillyl decenoate as a monomer for subsequent ADMET and thiol-ene polymerization. The esterification procedure had proven simple and effective for several previous esterifications involving different alcohol/acid combinations, but in this case the expected ester was not observed. Instead, a mixture comprised of unreacted perillyl alcohol and 9-decenoic acid and an unexpected and curiously high amount of p-cymene (31%; 4-isopropyltoluene) was obtained. With this serendipitous discovery in hand, we set out to improve the yield of industrially useful p-cymene from perillyl alcohol utilizing homogenous acid catalysis. We thus report the dehydration and isomerization of renewable perillyl alcohol as a 3.0 M solution in refluxing toluene to p-cymene in 91.1% yield utilizing catalytic para-toluenesulfonic acid. This approach represents a bio-based alternative to the conventional petrochemical Friedel-Crafts alkylation of toluene with propylene, which has several significant drawbacks. Industrial applications of p-cymene include use as a green solvent, heat transfer medium, ligand for catalysts, starting material for other industrial chemicals, and as a constituent in fragrances and perfumes.