A n equation is deduced relating the solubility 6 o f o r g a n i c s u b s t a n c e s in water t o their d i s t r i b u t i o n coefficient P I hexane and water, concentration C in their o w n phase. When the phase in e q u i l i b r i u m with water is crystalline,'the entropy of m e l t i n g A S the difference between the melting point !aatCa@ room temperature. and k M depend o n the n u m b e r n o f carbon atoms i n the molecule. In this c a s e t h e equation becomes : 108 s -A -0 . 5 9 7 n + log f , w h e r e the constant A is r e s p e c t i v e l y 2 . 4 0 , 2 . 6 9 and 3 . 0 5 f o r the p r i m a r y , secondary and tertiary alcohols. f is a c o r r e c t i o n factor which d e p e n d s o n C and o n k For solubilities lower t h a n 1 . 5 mol 1 the m e a n d e v i a t i o n b e t w e e n t h e computed v a l u e s and t h e literature d a t a is 10 Z in a range of s o l u b i l i t i e s f r o m O . O O O Z to I mol 1 I . at infinite d i l u t i o n b e t w e e n cyclotheir a s s o c i a t i o n c o n s t a n t k M in c y c l o h e x a n e and t o their to also i n t e r v e n e s a s well a s For the alcohols it a p p e a r s that both P I -1 For the phenols and the a n i l i n e s P I depends o n the m o l a r v o l u m e 4 and o n the pK , whereas k is m o r e or less influenced by the last factor. Or t h e basis o f a p r e v i o u s l y F s t a h l i s h e d c o r r e l a t i o n s b e t w e e n these quantities. t h e solubility of various a l k y l and halogenated d e r i v a t i v e s o f phenol and o f a n i l i n e are computed and compared with the experimental val; s .
T h e m e a n d e v i a t i o n is 2 5 Z f o r solubilities going from 0 , 0 0 7 to 0 . 9 mol 1 .
T h e most important factor d e t e r m i n i n g the solubility o f t h e phenols a p p e a r s to be their molar v o l u m e . T h e r o l e of the p K a of the p h e n o l s and o f t h e o r t h osubstituents is r a t h e r small a s a consequence of the c a n c e l l a t i o n of e f f e c t s of these f a c t o r s o n P and o n k . H o w e v e r , in the c a s e o f t h e a n i l i n e s t h e effect o f the p K f o n thiir solubirity r e m a i n s important.