A new selective route towards benzoic acid and derivatives from biomass-derived coumalic acid

Toni Pfennig, Jack M. Carraher, Ashwin Chemburkar, Robert L. Johnson, Austin T. Anderson, Jean Philippe Tessonnier, Matthew Neurock, Brent H. Shanks

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


The selective production of aromatics from bio-based sources is an area of interest to expand the potential for greener alternatives to petroleum-derived chemicals. A scalable, efficient route to produce bio-based benzoates is demonstrated by carrying out heterogeneous catalytic reactions in non-toxic bio-based solvents at 180°C obtaining yields of up to 100 mol%. This approach extends the 2-pyrone (coumalic acid/methyl coumalate) Diels-Alder platform by utilizing a bioavailable co-reactant ethylene. A detailed investigation using a combination of kinetic experiments, DFT calculations, and multi-dimensional NMR was carried out to determine the detailed reaction network, and the corresponding activation energies for critical steps. Additionally, a series of experiments were conducted to maximize the yields by comparing different solvents, for both coumalic acid and methyl coumalate. Our results show that the choice of solvent was a significant factor when coumalic acid was the reactant (yields 71-92 mol%), while methyl coumalate was only minimally affected by the solvent (yields 95-100 mol%). Interestingly, the reaction network and kinetic analysis showed that the Diels-Alder reactions were not significantly different between coumalic acid and methyl coumalate, with the rate limiting step for both being decarboxylation with an activation barrier of 141 kJ mol-1 compared to 77 kJ mol-1 for the formation of the bicyclic adduct. Finally, the reaction cascade was found to be highly susceptible to by-product formation when as little as 5 vol% water was present in the solvent, which demonstrates that the absence of water is essential for high yielding benzoate production.

Original languageEnglish (US)
Pages (from-to)4879-4888
Number of pages10
JournalGreen Chemistry
Issue number20
StatePublished - 2017

Bibliographical note

Publisher Copyright:
© The Royal Society of Chemistry 2017.


Dive into the research topics of 'A new selective route towards benzoic acid and derivatives from biomass-derived coumalic acid'. Together they form a unique fingerprint.

Cite this