Green synthesized biofuel meets auto standards

Researchers in Germany have developed chemical reactions that convert rapeseed oil and ethylene to a diesel fuel that could power conventional automobiles and trucks (Sci. Adv. 2017, DOI: 10.1126/sciadv.1602624). Biofuels derived from vegetable oils are often used as minor additives in conventional diesel fuel but frequently vaporize at temperatures too high to fuel vehicles on their own. Biofuels that vaporize more easily can be made from vegetable oils by hydroprocessing, a process similar to steam cracking, but the method is energy-intensive and expensive. Lukas J. Goossen of Ruhr University Bochum and coworkers have now identified palladium and ruthenium catalysts that accelerate isomerization and cross-metathesis reactions that make low-temperature-vaporizing diesel fuel from rapeseed oil. The reactions run at low temperature (60 °C), require no solvents, and produce no waste. They react fatty acid methyl esters from the oil with ethylene, potentially from bioethanol or shale gas, to form ester- and olefin-based biodiesel. The biofuel meets European and probably U.S. distillation-temperature standards, Goossen says. He and his coworkers demonstrated the biofuel by using it to power a model car with a diesel engine. The initial version of the process is expensive, but it’s a low-energy, sustainable alternative to hydroprocessing that could be optimized.