MEASUREMENT OF ACTIVITY-COEFFICIENTS AT INFINITE DILUTION USING GAS-LIQUID-CHROMATOGRAPHY - 7 - RESULTS FOR VARIOUS SOLUTES WITH N-METHYL-2-PIPERIDONE AS STATIONARY-PHASE

Activity coefficients at infinite dilution provide a useful tool for t he selection of solvents for extractive distillation or extraction. In this work activity coefficients at infinite dilution are reported for 36 solutes (alkanes, alkenes, alcohols, ketones, aromatic hydrocarbon s, cyclic hydrocarbons, aldehydes, ethers, esters, halocarbons, and ac etonitrile) in N-methyl-2-piperidone at three temperatures (303.41, 31 3.43, and 323.45) K, measured with the help of gas-liquid chromatograp hy. The experimental data are compared with data from literature and w ith the results of the modified UNIFAC (Dortmund) method. Furthermore the selectivity of N-methyl-2-piperidone for the separation of hexane from benzene was compared with the selectivity of N-methyl-2-pyrrolido ne and N-methyl-6-caprolactam. The observed temperature dependence of the activity coefficients at infinite dilution is confirmed using exce ss enthalpy data predicted with modified UNIFAC (Dortmund).