Application of Alkoxyalkanoates (AOAs) as Renewable Diesel Blendstocks from Chemical Coupling of High-Yield Fermentation Products

Abstract

Combustion of liquid fossil fuels for transportation is a major source of carbon emissions only partially offset by the incumbent renewable alternatives─biodiesel, renewable diesel, and ethanol. New renewable ground transportation fuels derived from abundant sources of biomass, and utilizing carbon-efficient bioprocessing, are needed to further offset fossil fuel use. Low carbon intensity liquid fuels are especially required for medium- to heavy-duty engine architectures supporting the long-range transportation fleet. Realization of substantial carbon efficiency gains in renewable fuel production can be achieved by extending feedstocks beyond lipids, which are the primary bioderived source material for biodiesel and renewable diesel. Toward these ends, chemical upgrading of the high carbon yield, central metabolism-derived intermediates, glycolic acid, lactic acid, and 4-hydroxybutyrate with various fermentation-derived alcohols was accomplished using standard chemical transformations to provide a class of compounds that show promise as an alternative to petroleum diesel. Fuel property testing of these C7–C22 hydroxyalkanoate-derived compounds demonstrated improved cold temperature performance compared to biodiesel (cloud point temperatures < −50 °C) and improved derived cetane number (DCN) and sooting metrics compared to renewable diesel, providing the technical basis for a new high-performance renewable blendstock for decarbonization of heavy-duty transport.