Branched-Chain Fatty Acids Based On Biomass Fast Pyrolysis Phenolics

Demand for bio-based petrochemicals has increased across all product types. Included are phenolic compounds and their derivatized products. Thermochemical conversion, especially pyrolysis, offers one of the strongest opportunities for producing advanced biofuels and phenols. Previous work showed that various unsaturated fatty acids (soybean, brown grease, safflower [SF]) can react with phenol across the fatty acid double bond(s) via the branched-chain fatty acid (BCFA) synthesis. Although phenolic BCFAs offer a gateway toward bio-based antimicrobial coatings, the phenolic component has remained dependent on fossil-derived phenol. We have closed this gap by incorporating refined biophenolics fraction from pyrolysis in the BCFA synthesis. Pyrolysis-derived phenols are incorporated in the synthesis, thus making the biophenolic BCFA fully biorenewable. Catalytic fast pyrolysis of switchgrass produced bio-oils with sufficiently high concentrations of phenol and cresols (biophenolics). These one-ring biophenolics were extracted and redistilled, yielding a fraction of >75 wt% phenols. SF and pennycress (PC) oils were hydrolyzed and subsequently functionalized with biophenolics using a ferrierite zeolite catalyst. Excess biophenolics were removed using molecular distillation. Yields of biophenolic BCFAs ranged from 63% to 76%. Antimicrobial tests show activities against strains of Listeria bacteria.

Practical Application: This work significantly increases the utilization of chemicals isolated from biomass fast pyrolysis oils. We also expect that these findings will accelerate incorporation of green methods for antibacterial coatings in clinical applications.