Study of gas-liquid partitioning of alkane solutes in several organic solvents by using principal component analysis and linear solvation energy relationships

摘要

Principal component analysis (PCA)was used to extract the number of factors which can descripe the 737 gas-liquid partition coefficients of five limera four baranched and two cyclic alkanes in 67 common solvents Base on te reconstruction of partition coefficient data matrix we concluded that the experimental dataset couldreadily be resuced to two relevent factors Using only these two factors theere were no errors larger than 3% 7 cases had errosr larger than 2% and in 34 cases errors were between 1 and 2% n-Hexane and ethylcyclohexane were chose as the test factors and all other partitin coefficients were expressed in term of these two test factors Prediction of the logarithmic partition coefficient of these alkanes in seven chemically different solvents which were originaly excluded fromthe data matrix was excellent the root maan square error was 0.064 only in 11 cases the errors were larger than 1% and only 3 had errors larger than 4%.Linear solvatin energy relatinships (LSERs) using both theoretical and empirical solvent paramethers wer eused to explain teh molecular interadtons responsible for partitin Sevedral combinatins of parameters were tried but th estandard deviations were not less than 0.31 This could be attriguted to the model itself imprecisions in the data matriz or in some of the LSER parameters Solvent cohesive parameters snd surface tension in combination with polarity-polarizability or dispersion parameters perform the best.Finally the two principal component factors were rotated onto the most relevat physicochemical parameters that conrol the gas-liquid partitioning phemomena.