A Classroom Demonstration of Water-Induced Phase Separation of Alcohol–Gasoline Biofuel Blends

• Autores: Sherry A. Mueller, James E. Anderson, Timothy J. Wallington
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 86, Nº 9 (September), 2009, págs. 1045-1048
• Idioma: inglés
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• Resumen

  • A significant issue associated with ethanol–gasoline blends is the phase separation that occurs with the addition of small volumes of water, producing an ethanol-deficient gasoline layer and an ethanol-rich aqueous layer. The gasoline layer may have a lower-than-desired octane rating due to the decrease in ethanol content, resulting in engine knock, while the ethanol-rich aqueous layer may not support combustion. Ethanol and ethanol–gasoline blends are not distributed via gasoline pipelines (in which water may be present), but are often proportionally blended just prior to delivery to retail outlets. We report a simple demonstration that effectively illustrates this issue by inducing a phase separation upon addition of a small volume of water to various alcohol–gasoline blends.