Molecular electronegative distance vector (MEDV) related to 15 properties of alkanes

Several quantitative structure-property relationship (QSPR) models between 15 basic physical properties or thermodynamic functions of alkanes and thei r molecular electronegative distance;vectors (MEDV) are developed. For six of the properties-boiling point (BP), density (D) at 25 degreesC, refractio n index (RI) at 25 degreesC, critical temperature (CT), critical pressure ( CP), and surface tension (ST)at 20 degreesC-logarithmic models are found to give better results than conventional (linear) models since the values of these properties all tend to a,limit with increasing carbon chain length. A ll models are created using multiple linear regression (MLR). Conventional models are proposed for the remaining nine physical properties or thermodyn amic functions: molar volume (MV) at 20 degreesC, molar refraction (MR) at 20 degreesC, heat capacity (HC) at 300 K,; enthalpy (E) at 300-K, heats of vaporization (HV) at 25 degreesC, heat of atomization (HA) at 25 OC, standa rd heat of formation (HF) at 25 degreesC, heat of formation in liquid (HFL) at 25 degreesC, and heat of formation in gas (HFG) at 25 degreesC.