Composition-Explicit Distillation Curves for Mixtures of Gasoline with Four-Carbon Alcohols (Butanols)

Interest in the domestic production of bioderived fuels, sparked by the high cost of petroleum crude oil, has led to consideration of fluids to replace or extend conventional petroleum-derived fuels. While ethanol as a gasoline extender has received a great deal of attention, this fluid has numerous problems, such as aggressive behavior toward engine components and a relatively low energy content. For these and other reasons, the butanols have been studied as gasoline extenders. For any extender to be designed or adopted, a suitable knowledge base of thermophysical properties is a critical requirement. In this paper, we provide volatility measurements of mixtures of a typical gasoline with n-butanol, 2-butanol, isobutanol, and t-butanol, performed with the advanced distillation curve metrology. This recently introduced technique is an improvement of classical approaches, featuring (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analyses), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, (6) trace chemical analysis of each distillate fraction, and (7) corrosivity assessment of each distillate fraction. We have applied the new method to fundamental work with hydrocarbon mixtures and azeotropic mixtures and also to real fuels. The fuels that we have measured include rocket propellants, gasolines, jet fuels, diesel fuels (including oxygenated diesel fuel and biodiesel fuels), and crude oils.