VAPOR-LIQUID-EQUILIBRIA OF HYDROCARBONS AND FUEL OXYGENATES .2.

Vapor-liquid equilibrium data for methyl tert-butyl ether (MTBE) + 1-h eptene, MTBE + four-component gasoline prototype, ethanol + four-compo nent gasoline prototype, and separately MTBE and ethanol with the Auto /Oil Air Quality Improvement Research Gasoline Blend A are reported. S mall additions of MTBE have a very small effect on the total equilibri um pressure of this gasoline blend, and at most temperatures will decr ease this pressure. In contrast, small additions of ethanol to this ga soline blend result in a significant increase in the equilibrium press ure at all temperatures. Analysis shows that the vapor-liquid equilibr ium data for the MTBE-containing systems are easily correlated using a modified Peng-Robinson equation of state with conventional van der Wa als one-fluid mixing rules. Data for mixtures containing ethanol canno t be accurately correlated in this way.