Novel applications of topological indices. 3. prediction of the vapor pressure in polychlorinated biphenyls

In an attempt to correlate the vapor pressure of polychlorinated biphenyl compounds with their molecular structure, use was made of a number of topological indices. Included in our study were the Wiener index, W; the Balaban distance sum connectivity index; J; several of the Randić molecular connectivity indices, namely ⁰ χ through ² χ, ³ χ _p through ⁶χ_p, ³ χ _c through ⁵ χ _c, ⁴ χ _pc through ⁶χ_pc and ⁶χCH (both simple and valence terms); and the chlorine number, n _CI. Excellent correlations were obtained for two different temperatures, viz. 25°C and 100°C. It is demonstrated that the indices which correlate best at these two temperatures are in general not the same.

Key words:

• Vapor pressure
• topological indices