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Influence of the Reaction Conditions and Molecular Structure on the Kinetic of the Nucleophilic Aromatic Substitution of Fluoro Compounds with Poly(vinyl amine) in Water
Author(s) -
Hofmann Katja,
Roth Isabelle,
Spange Stefan
Publication year - 2012
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201200115
Subject(s) - chemistry , polymer chemistry , nucleophilic aromatic substitution , amine gas treating , intermolecular force , activation energy , nucleophilic substitution , hydrogen bond , nucleophile , photochemistry , medicinal chemistry , organic chemistry , molecule , catalysis
The nucleophilic aromatic substitution (NAS) reaction of various fluoroaromatic/2,6‐ O ‐dimethyl‐ β ‐cyclodextrin complexes with poly(vinyl amine) (PVAm) has been studied in water at different pH. Increasing pH lowers the notable negative activation entropy of those types of NAS due to the PVAm chain segments becomes better accessible in basic media. At pH > 7, the zwitterionic intermediate in the course of NAS seems stabilized by intermolecular hydrogen bonds, which has an influence on the increase of activation energy for elimination the fluoride ion. As a consequence, the counter balance between activation entropy and activation energy determines the rate of the NAS with PVAm, which is shown for several functional fluoroaromatic compounds including fluoronitrobenzenes, fluoronitroanilines, and imine bases.