Determination of Aromatics in Light Petroleum Distillates By Use of Specific Dispersions between Sodium D Line and Mercury g Line

The aromatic content of a hydrocarbon mixture in the gasoline boiling range containing no olefins or diolefins may be determined from the refractive indexes for the mercury g and the sodium D lines, and from the density, all determined at 20/sup 0/C. The percent aromatics in the mixture may then be obtained from the equation: W = S/sub s/ - 122.4/S/sub a/ - 122.4 x 100 + C. The values of specific dispersion for the several aromatics are: benzene, 248.4; toluene, 241.4; ethylbenzene, 228.1, o-xylene, 234.8; m-xylene, 237.1, p-xylene, 238.2; and isopropylbenzene, 215.8.