Are all oxygenated gasolines also reformulated gasolines?
No. Oxygenates were initially introduced as alternative octane-enhancers in the 1930s, and are still used in some countries for that purpose. In the US the original “oxygenated gasolines” usually had a slightly- modified gasoline as the hydrocarbon fraction. The US EPA also mandated their use to reduce pollution, mainly via the “enleanment” effect on engines without sophisticated management systems, but also because of the “aromatics substitution” effect. As vehicles with fuel injection and sophisticated engine management systems became pervasive, reformulated gasolines could be introduced to further reduce pollution. The hydrocarbon component of RFGs is significantly different to the hydrocarbon fraction in earlier oxygenated gasolines, having lower aromatics contents, reduced vapour pressure, and a narrower boiling range. RFGs do contain oxygenates as the octane-enhancer, but have different hydrocarbon composition profiles [34,41,42,43,44].
