Lignocellulosic biomass offers a renewable carbon source which can be anaerobically digested to produce short-chain carboxylic acids. Here, we assess fuel properties of oxygenates accessible from catalytic upgrading of these acids a priori for their potential to serve as diesel bioblendstocks. Ethers derived from C2and C4carboxylic acids are identified as advantaged fuel candidates with significantly improved ignition quality (>56% cetane number increase) and reduced sooting (>86% yield sooting index reduction) when compared to commercial petrodiesel. The prescreening process informed conversion pathway selection toward a C11branched ether, 4-butoxyheptane, which showed promise for fuel performance and health- and safety-related attributes. A continuous, solvent-free production process was then developed using metal oxide acidic catalysts to provide improved thermal stability, water tolerance, and yields. Liter-scale production of 4-butoxyheptane enabled fuel property testing to confirm predicted fuel properties, while incorporation into petrodiesel at 20 vol % demonstrated 10% improvement in ignition quality and 20% reduction in intrinsic sooting tendency. Storage stability of the pure bioblendstock and 20 vol % blend was confirmed with a common fuel antioxidant, as was compatibility with elastomeric components within existing engine and fueling infrastructure. Technoeconomic analysis of the conversion process identified major cost drivers to guide further research and development. Life-cycle analysis determined the potential to reduce greenhouse gas emissions by 50 to 271% relative to petrodiesel, depending on treatment of coproducts.

Applying a rational design approach to produce a high-quality, low-sooting hydrocarbon diesel blendstock from lignocellulosic biomass-derived short-chain carboxylic acids.

Camphorene was synthesized by the thermal Diels–Alder cyclodimerization of myrcene and subsequently hydrogenated to produce camphorane. On the basis of common fuel metrics (density, lower heating value, cetane, and viscosity) the prepared camphorane fuel displays appropriate physicochemical properties for its implementation in compression ignition engines. The high viscosity of camphorane necessitates its blending with petroleum diesel, which provides a final fuel within the ASTM specification for diesel. Soot production measurements of camphorane and its blends with diesel demonstrate a potential to significantly reduce soot emissions. The physicochemical and combustion properties of camphorane are further compared to those of other terpene biofuels along with biodiesel.