Pair-wise interactions by gas chromatography VII. Interaction free enthalpies of solutes with secondary alcohol groups

A polar type liquid having a secondary alcohol substituent on a branched al kane skeleton, SOH, was used as stationary phase. The molecules of this sta tionary phase are nearly isomorphous and isochor with those of the branched alkane, C-78, elected as standard, i.e., the molecules of both solvents ha ve nearly the same form and the same size. Partition properties of 158 chos en molecular probes were measured by gas chromatography on SOH and on an SO H-C-78 mixture having a volume fraction of phi (SOH)=0.5. Based on the resu lting data an interaction free enthalpy could be calculated, i.e., the addi tional effect of the secondary alcohol to partition. Comparison with data d etermined earlier on another member of this solvent family, POH, having a p rimary alcohol as interacting group gives information about the effect of s teric hindrance on polar type solute-solvent interaction free energies. (C) 2000 Elsevier Science B.V. All rights reserved.