Correlation studies on vapor pressures and critical properties for isomeric alkanes

Abstract

In SPITE of the great amount of effort that has been expended in developing correlation procedures for physical properties of branched alkanes, the authors still find the situation in a somewhat unsatisfactory state. Furthermore, recently additional, precise data have become available (1, 12), which serve as an incentive to re-examine the status

The vapor pressure of n-alkanes revisited. New high-precision vapor pressure data on n-decane, n-eicosane, and n-octacosane

“…Measurements on both compounds illustrate the range of our present apparatus. The results are compared with literature data [API 42 (6), Macknick and Prausnitz (7), and Myers and Fenske (8)] and the correlation used in the derivation of the values reported in the current TRC tables (1,2).…”

Critical Properties of Hydrocarbon Systems

“…Some of those are dealing only with critical data of pure paraffines, as for instance the methods published by Riedel [9] and by Kudchadker et al [10]. An interesting approach was made by Thodos [11], who developed increments for the van der Waals parameters a and b of paraffines.…”

An empirical method for evaluating critical molar volumes

“…Empirical correlations for evaluating critical volumes have been reviewed by Reid and Shenvood ( 1966) ) , Kudchadker et al ( 1968a), and Spencer and Daubert (1973). Only recent developments or methods of wide applica- (1) f The more recent modification of this method is reported by Fedors ( 1973), which simply states v, = PAUi…”

“…More recently, Viswanath (1968) has proposed the ideal critical volume V c i = RT,/P, as a correlating parameter for V , following the relationship V, = 10.0 + 0.259 V,, A first comparison between correlations of the two types for different classes of compounds, chosen among those reported by Kudchadker et al (1968a), clearly shows the superiority of the relationship based on the group contributions method with respect to the other methods (see, for example, Table 2). This fact is not surprising, since the critical molar volume appears to be a typical additive property.…”