| The steady state diffusion rates of fifty-five aliphatic compounds through polydimethylsiloxane membrane were determined using isopropanol as solvent. The compounds ranged from nonpolar to semipolar liquids and included alkanes, chloroalkanes, ethers, ketones, esters, acids, amines and alcohols. Two approaches were developed which allowed prediction of diffusion rates.;The first predictive method correlated the flux with physico-chemical properties represented by hydrophobic, molar volume and hydrogen bonding characteristics of the penetrants. A simple regression model correlating the flux to the boiling point of the penetrant was found. The predictive power of this empirical relationship was excellent. The consistency and reliability of the model was demonstrated by randomly choosing three sets of eight compounds, deleting these compounds from the model and recalculating the regression coefficients. The prediction of the experimental flux values were within plus or minus 25%.;The second predictive method used a fragmental approach which was used to assess the contribution of the various functional groups. The first model fragmented the compounds into the following simple groups: CH... |
