Partition Coefficients and Surface Areas of Some Alkylbenzenes

The experimentally measured log P values (logarithms of partition coefficients) of a number of alkylbenzenes are shown to be quantitatively related to the hydrocarbon surface area HSA of the molecule by π = 0.0275 × HSA - 0.863 (correlation coefficient = 0.996, standard deviation = 0.071). The use of surface area as a correlating parameter eliminates the need for correction factors to account for branching, cyclization, ring fusion, and “backfolding”. Furthermore, surface area calculations provide a conceptual basis for understanding how conformation can effect partitioning.