Qualitative understanding of partition preferences

Introduction
Cavity model
Rules for partitioning ...
     ...of a given compound
           Recall information ...
           Case Ia
           Case Ib
           Case Ic
           Case IIa
           Case IIb
           Other cases
           Overview
           Furter information
     ...of various compounds
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The cavity model in quantitative terms

Selftest
Problems
Intermolecular interactions in every day life
FAQ

Rules for partitioning of various compounds (4/5)

Partitioning between an organic phase and water: Combining the statements from Rule 7, 8 and 9 we get:

Rule 10:
Logarithmic organic phase/water partition constants, log Ki org./water, increase linearly with molecular size for compounds that otherwise possess identical functional groups. For bipolar organic phases this increase becomes smaller (i.e., shallower slope) with increasing cohesive energy.

This rule is illustrated in Figure 6 .

 

Figure 6: Increasing molar volume shifts the octanol/water partitioning towards the organic phase.

 

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