New possibilities in the synthesis of fuel oxygenates from renewable sources

Abstract

A general problem in the production of the main types of liquid biofuel, bioethanol and biodiesel, is that renewable resources are not utilized completely. These are ballast polyols: hemicellulose or its structural units, pentaatomic monosaccharides (xylose and arabinose), and biodiesel glycerol. The problem of utilization of these compounds by transforming them into a hydrophobized fuel form by the conversion to cyclic ketals (CK) during condensation with lower carbonyl compounds is reviewed. The CK—ethanol pair significantly increases the octane number and provides phase stability of fuel compositions. The ability of CK to inhibit radical processes responsible for fuel characteristics was studied in model reactions with phenyl radicals and atomic chlorine. The carbon-centered radicals formed in protic media are transformed into more stable cyclic radical cations. Alternative methods of processing natural raw materials using biocatalysis and supercritical fluid technologies are analyzed.