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Elimination in sulfobetaine micelles: effects of head group bulk
Author(s) -
Brinchi Lucia,
Germani Raimondo,
Savelli Gianfranco,
Bunton Clifford A.
Publication year - 1999
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199912)12:12<890::aid-poc214>3.0.co;2-2
Subject(s) - micelle , chemistry , reaction rate constant , sn2 reaction , cationic polymerization , bromide , reaction rate , organic chemistry , photochemistry , medicinal chemistry , kinetics , aqueous solution , catalysis , physics , quantum mechanics
Zwitterionic micelles of tetradecyldimethylammoniopropanesulfonate and tetradecyldibutylammoniopropanesulfonate, SB3‐14 and SBBu3‐14, respectively, accelerate the E 2 reaction of OH − with 4‐nitrophenethyl bromide ( 1b ), but the reaction of phenethyl bromide ( 1a ) is inhibited by SB3‐14 and is only slightly accelerated by SBBu3‐14. Analysis of these data allows the separation of the association constants for transfer of reactants from water to micelles from the second‐order rate constants in the micelles. These second‐order rate constants are, as in water, larger for 1b than 1a , and for both substrates are higher in SBBu3‐14 than in SB3‐14, as found for reactions in otherwise similar cationic micelles. Rate constants in micelles, relative to those in water, are consistently higher in E 2 than in S N 2 reactions. Copyright © 1999 John Wiley & Sons, Ltd.