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Relative Gas‐phase Acidities of Fluoro‐ and Chlorobenzene
Author(s) -
Andrade Paula B. M.,
Riveros José M.
Publication year - 1996
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199607)31:7<767::aid-jms345>3.0.co;2-q
Subject(s) - fluorobenzene , chemistry , chlorobenzene , ion cyclotron resonance , equilibrium constant , fourier transform ion cyclotron resonance , ion , analytical chemistry (journal) , gas phase , yield (engineering) , mass spectrometry , thermal equilibrium , phase (matter) , resonance (particle physics) , thermodynamics , organic chemistry , chromatography , catalysis , atomic physics , benzene , cyclotron , physics
The gas‐phase equilibrium reaction between fluorobenzene and chlorobenzene and their conjugate bases was studied by Fourier transform ion cyclotron resonance spectrometry in order to reconcile conflicting experimental results obtained using different techniques. The results of a large number of measurements yield equilibrium constants which show chlorobenzene to be more acidic than fluorobenzene by 0.55±0.15 kcal mol ‐1 (Δ G ° at 330 K). Different control experiments were carried out to ensure that the measured equilibrium constants reflect adequately the thermal distribution of the different isomeric halophenide ions.