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Solvation of Substituted Phenoxide Ions in T‐Butyl Alcohol‐Water Mixtures, from Kinetic Studies of Proton Exchange
Author(s) -
Grunwald E.,
Fong D.W.,
Ralph E.K.
Publication year - 1971
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197100046
Subject(s) - chemistry , solvation , alcohol , ion , proton , ionic bonding , tert butyl alcohol , reaction rate constant , base (topology) , molecule , inorganic chemistry , kinetics , organic chemistry , mathematical analysis , physics , mathematics , quantum mechanics
Rate constants (k 2W or k 2A ) for proton exchange between a phenol, its conjugate base, and a water or t ‐butyl alcohol molecule have been measured in a t ‐butyl alcohol‐water mixture by nuclear magnetic resonance. Since k 2W and k 2A are both high (k 2W > 10 8 sec −1 M −1 ), the ratio k 2W /k 2A measures the selective solvation of the O − ‐site (of the phenoxide ions) by water and t ‐butyl alcohol. In 11.47 mole % t ‐butyl alcohol — 88.53 mole % water, k 2W /k 2A is found to be 14 ± 3 when the ionic reactant is ortho ‐bromophenoxide ion, and 32 ± 8 when it is meta ‐nitrophenoxide ion. The results suggest that substituents have a marked effect on the selective solvation of the O − ‐site.