Biobutanol extraction and dehydration with eucalyptus oil yielding linear and cyclic biofuel blends

The biobutanol-based biofuel fermentation is hindered by the challenge of inadequate fermentation broth concentration and the azeotropic systems of water. The application of eucalyptus oil in diesel fuel makes it a promising extractant for biobutanol extraction and dehydration, thus resulting in product recovery and the development of fuel blend technology. Eucalyptus oil-derived 1,8-cineole was applied to acetone-butanol-ethanol (ABE) and isobutanol systems to enhance the butanol recovery and dehydration. The recovery of n-butanol and isobutanol reached 92% and 95%, respectively, while the water removal in a 2% butanol system exceeded 99%. These results demonstrated that 1,8-cineole exhibited a high selectivity toward butanol, thus providing a robust theoretical foundation for the fermentation-based biofuel recovery and the elimination of azeotropic systems. The introduction of high-density diesel-fuel-like eucalyptus oil into low-energy-density biobutanol will increase the energy density of fermentation-based alcohols, yielding linear and cyclic biofuel blends.