Internally Consistent Prediction of Vapor Pressure and Related Properties

Abstract

A new vapor pressure model containing one parameter is presented. The vapor pressure curves of all hydrocarbons that may contain heteroatoms merge together at a common point. Thus, the vapor pressure curve can be predicted using one known data point. If no data are available, the characteristic parameter can be obtained using structural information about the component. Since vapor pressure curves end in their critical points, the equation allows internally consistent prediction of critical pressure from known critical temperature, or vice versa, and for predicting the acentric factor. For calculating the heat of vaporization at any temperature using the Clapeyron equation, knowledge of the nonideal behavior of a component along the vapor pressure curve is needed. The equations presented for this purpose show excellent agreement for all components for which experimental data have been found.

Viscosity of liquid hydrocarbons and their mixtures

“…The Clapeyron equation has the same mathematical form as the Andrade equation, and the Antoine equation is equivalent to the Vogel equation, for instance. Recently, a new model for predicting vapor pressure curves as a function of structural composition over wide temperature ranges has been proposed (Korsten, 2000). By introducing pa, the viscosity at the temperature T,, one might apply that model to viscosity Figure 2, the results look promising.…”

A Calculation for the Viscosity of Fluid at the Critical Point

“…Besides, few theories have been developed for the quantitative prediction of the viscosity at the critical point. Recently, a new model 14 for predicting vapor pressure as a function of structural composition over wide temperature ranges has been proposed, but it can not predict the right shape of the viscosity curves at temperatures greater than about 0.7 times the critical temperature. Until now, η c has been estimated in one of the following ways; (i) if a value of viscosity is known at a given reduced pressure and temperature, preferably at condition as near to those of interest as possible, then η c = η/η r , where η r is reduced viscosity; or (ii) if only critical P-V-T data are available then η c by Bird 8 may …”

Critical properties of some tetraalkoxysilanes and tetraalkoxytitaniums with branched alkyl radicals

“…For comparison, the table also contains the properties of the isomers with straight alkyl chains taken from our previous paper [3]. In that paper, the Filippov parameters and the correction factors of the compounds were estimated using the equation for vapor pressure suggested by Korsten [30]:…”