Thermodynamic Properties of Ethylbenzene Vapor from 300° to 1500°K

Abstract

In this paper are presented tables of the more important thermodynamic functions of ethylbenzene in the ideal gas state from 300° to 1500°K. These functions were calculated using spectroscopic, structural, and calorimetric data. Six investigations of the Raman spectrum of ethylbenzene and three of the infra-red absorption spectrum were available for an assignment of frequencies to the intramolecular vibrations. Included in the paper is a calculation from calorimetric data of the enthalpy and entropy of saturated vapor at 294°K relative to the solid at 0°K. This paper completes a report on a determination of the thermodynamic properties of ethylbenzene covering the solid, liquid, and vapor phases, extending from 0° to 1500°K. All the experimental results are presented in detail in preceding papers.

Vibrational frequencies of semirigid molecules: a general method and values for ethylbenzene

“…In the present method, in which 8;2 rather than G;2 is computed, it is convenient to convert eq 22 to the secular equation of a single matrix, in the form (24) In practice, F22 is diagonal, or nearly so, and therefore easily reciprocated. The roots of eq 24 are, of course, the reciprocals of the A's.…”

“…Previou s investigators have assigned the two B2 frequencies as 71"-(748) and 71"3 (1179), bu t the assignment of these frequencies in table 4 is supported by (1) the force constan ts obtained for CP3, <13, and 71"3, which shou ld have approximately the proportions 2,1, and 1, r espectively (these figures assume that interaction constants are negligible, and that the main constants arise from the constants for the four C-C-J-I angles), and (2) the approximate equality of th e force constants ob tained for 71"-and <1-. The n ext column of table 4 gIves the valu e of A (eq 22 to 24) in the units…”

Thermodynamic properties of solid and liquid ethylbenzene from 0 to 300 degrees K

“…The vapor-pressure equation, 1, was used with the Clausius-Clapeyron relation dp L.=T(V-v) dT (2) to calculate the heat of vaporization of 294.01 ° K and thus provide a check on the accuracy of the measurements. In equation 2, Lv is the heat of vaporization, V is the specific volume of the saturated vapor, v is the specific volume of the liquid, and dp /dT is the derivative of the vapor-pressure-temperature relation.…”

“…The measurements of the thermal properties of solid and liquid ethylbenzene described in this paper were undertaken as part of a program to obtain thermodynamic data on ethylbenzene covering the solid, liquid, and vapor phases and extending from 0° to 1,500° K. A calorimetric measurement of the specific heat of the vapor at 373.16° K was reported in an earlier paper [1] 1; the calculated thermodynamic functions for the vapor from 300° to 1,500° K are reported in another paper [2]. 1 Figures in brackets indicate the literature references at tbe end of this paper.…”

Rubber research and technology at the National Bureau of Standards/

“…In addition, similar studies have been made on materials important in the production of styrene, namely ethylene [86,88,90], benzene [87,99], and the alkylbenzenes [87,89,99], especially ethylbenzene [92,93,98].…”