New convenient vapor pressure-temperature correlation for some aliphatic hydrocarbons

Abstract

New empirical equations for correlating temperature dependence of vapor pressure for C6-C20 aliphatic hydrocarbons are proposed: ln(VP) = k1·T/(k2+T) where, VP – vapor pressure, T – temperature, k1 – asymptotic maximum vapor pressure, and k2 – temperature at which the vapor pressure has half of its maximum value. Descriptors k1, k2 and k1/k2 have physical meaning and are unique for a given liquid. This “uniqueness” can be exploited for quantitative description of vapor pressure-temperature curve. The equation given above can be transformed algebraically into other convenient forms for plotting experimental data such as: T/ln(VP) = intercept + slope·T k1 = 1/slope; k2 = intercept/slope These derived descriptors can be utilized for evaluation and comparison of properties of different liquids and liquid mixtures and can serve as additional parameters for analysis of liquid hydrocarbon-based fuels for internal combustion engines.