Ebulliometric and tonometric measurements on normal aliphatic hydrocarbons

Abstract

By the application of the precise method developed by W. Swietoslawski for measuring the boiling points and the differences between boiling point of liquids and the condensation tempcrature of their vapors, it is possible to determine several facts of interest to the chemist. Among these are the purity of the substance under investigation, its boiling point, and the relation of boiling point to pressure.The normal hydrocarbons, pentane, hexane, heptane, and octane have been studied by this method. The ebulliometric control of purity of the preparations, the use of substances of high purity, and the application of a method of comparative measurements insure the accuracy of the results r eported.The numerical data are as follows: n-pentane, boiling point 36.077, ~~ =0.0391; n-hexane, boiling point 68.733 ddt =0.0420; n-heptane, boiling point 98.365, , P :! =0.0449; n-octane, boiling point 125.658, :! = 0.0477.

Ebulliometric and tonometric study of normal aliphatic alcohols

“…The data previously reported on the normal aliphatic hydrocarbons, together with the data presented in this paper, suggest the following generalization: In any organic molecule containing a normal alkyl group of more than some small number n of carbon atoms, the addition of a CH2 group to the normal alkyl group to form the next higher normal alkyl group results in an increase of 0.0029° C. per millimeter of mercury in the coefficient ~~ at the normal boiling point. The data reported in this paper indicate that for the normal aliphatic alcohols n=2, while the data reported in the paper [1] on the normal aliphatic hydrocarbons indicate that for these compounds n is not greater than 4. It is possible that :; may be an additive property, the value of which may be calculated by taking the sum of the values corresponding to all atoms in the molecule of a given compound.…”

“…In a previous paper [1]2, it was shown that in the homologous series of normal saturated hydrocarbons from n-pentane to n-octane, inclusive, the coefficient of increase of boiling point with pressure, I Guest Worker, from tbe Polytecbnic Institute, Warsaw, Poland. , The figures in brackets throughout this paper refer to the numbered references listed at tbe end of tbe paper.…”

Boiling points and densities of acetates of normal alphatic alcohols

“…In previous papers it was shown that in the homologous series of normal saturated hydrocarbons [11] 2 and normal aliphatic alcohols [12], containing more than some small number n of carbon atoms, the addition of a CH2 group to the normal alkyl group to form the next higher normal alkyl group results in an Increase of 0.0029° C per millimeter of mercury in the coefficient dt/dp at the normal boiling point. Since this value was found to be independent of the chemical nature of the compound, the additivity of the effect of the CH2 group on dt/dp was postulated.…”

“…For determining boiling points Swi~toslawski's ebulliometric technic [7] and comparative method with water as a primary standard was applied. Details of the experimental procedure for determining the boiling point and the coefficient dt/dp have been described briefly in the paper on hydrocarbons [11]. Temperatures were measured with a platinum-resistance thermometer having a coiled filament [4], calibrated at this Bureau and furnished by C. H. Meyers.…”

Separation of the three methyloctanes from midcontinent petroleum

“…The freezing and melting curves shown in figures 7 and 8 indicate that the sample of 2-methyloctane was probably 99.9 mole percent pure 9 and that the 3-methyloctane was sufficiently pure to establish its identity. Since nearly all of the latter froze within 2° C, its freezing point probably lies within a degree of that of pure 3-methyloctane.…”