Molecular Volumes of Mononuclear Aromatic Hydrocarbons.

Abstract

T h e inolecular *olunies of 1-phenylalkanes and 2-pheii) 1-alkanes at any @\en fraction of the critical temperature are linear functions of the nuniber of carbon atoms. RIolecuIar\ olunies of fourteen homologous series of mononuclear aromatic h>drocarbons at 20' C. are also linear functions of the number of carbon atonis. Both of these relationships may be expressed by equations of the forni : M / d = V = a -+ bn Constants a and b are simple functions of the reduced temperature. These functions may be expressed by equations of the form :study reported her<% correlates existing density d:ita THE with structure for fourteen homologous series of mononurlcar aromatic hydrocarbons, and thus provides n method for cstirnntiug the molecular volumes (molecular weiplit divided by t1r:nsity) and densities of unknown or unmcasurctl Incmhcrs of t h r serica.('omparison:: of moleuuinr volumes must he m:i& a t specified temperatures berause of the variation of density with tempcrature. Compari3ons niny be made a t u constant tempcrnturc,, such as 20" C,. ( 1 , 2 , Y,, 9, 10, 12, 13, 16, 18), or at characteristic tcmperatures wi>h :ID the boiling point (6, 1 4 ) , the melting point (8,16), or a yivisn fraction of the c?itical temperature. 'rhc 1;ittcr is preferred ( 5 ) when thc necessary dnta :w available.The studies already published arc. concerned principally with aliphatic and alicyclic compounds. The present corrclation was carried out for fourtt.c.11 homologous series of arom:itic 1Iydroc:irbons a t 20' c.nncl for tvio series a t corre--1)oncling reduced temperatures (fr.ictions of the critical templXr:ltures). By both of these nwthods the molecular volume IY:IS found t o 1,c :In ntlditirc function oi thc. iiunit)i,1, cJi' w rt,oil atom-\vitllin :i I~OIY.O~OKOLIS .-i.ries. This 1elation>nip may I W c*spressud LIT 1 II(' c~qmitiori

Properties of Alkylbenzenes.

“…In order to judge the reliability of an observation or to choose between badly discrepant ones, it is desirable to have a comprehensive correlation between the properties and structures of hydrocarbons. Three papers by Corbin, Alexander, and Egloff (70,71,72) have already correlated the properties of the simpler types of alkylbenzenes,-namely, the 1-and 2-phenylalkanes,-and some of the dialkylbenzenes, but less than one-seventh of the total number of known alkylbenzenes are included. In a fourth paper (73) the same authors showed the relation of boiling point to pressure for some additional alkylbenzenes.…”

Gaps in Physical Constants Data for Hydrocarbons

“…The boiling-point calculations of Burnop (1), Klages (20), and Kinney (17,19) can be applied to mononuclear aromatics, and correlations of boiling point, molecular volume, and molal refraction have been worked out for several homologous series by Corbin, Alexander, and Egloff (3,4,6).…”