Raymond B. Seymour,' Ezequiel R. Rivera and Faith I. Smith SVIROSS State College Alpine, Texas
The Betachor: A New
I
Parameter for Hydrocarbons
Values for index of refraction, density, and other readily determinable physical constants have been used to derive several useful parameters for the characterization of hydrocarbons. Straight lines with characteristic slopes have been obtained by plotting any of the following properties for homologous series against the number of carbons in the hydrocarbon: index of refraction a t 25'C; density (g ml-' at 25OC); melting point (OC); or the reciprocal of the boiling point (OC). The relationship n Tbd-I [the product of refraction a t 25"C, the boiling point (OK) and the reciprocal of the density (g ml-' a t 25'C)], termed the Betachor, also yields straight lines when these data for a homologous series are plotted against the number of carbon atoms present in the hydrocarbon. The scales for the abscissa and ordinate are not linear but are consistent for all known data. The accompanying figure demonstrates the relationship of the Betachor and carbon number for several types of hydrocarbons. Readen desiring additional information on relationships of these properties for a wide variety of hydrocarbons may obtain these data by writing to Dr. Raymond B. Seymour. 'Present address: Depmtment of Chemistry, University of Houston, Houston 4, Texas.
332 / Journal o f Chemical Education
A. I-Alkonc* B. Alkyl Styrenes C. Cyclopentonaa. olso. I-Alkyncs D. I-AIkyl Nopholencs E. Alkyl Toluenes F. I-Alkenea
580 700
820
940
1060
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