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Gas phase relative proton affinities from selected‐ion flow tube (SIFT) rate constant measurements
Author(s) -
Dotan I.,
Iraqi M.,
Petrank A.,
Lifshitz C.,
Viggiano A. A.
Publication year - 1992
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290060909
Subject(s) - chemistry , equilibrium constant , reaction rate constant , acetaldehyde , analytical chemistry (journal) , endothermic process , proton , methanol , affinities , ion , gas phase , thermodynamics , ethanol , chromatography , stereochemistry , kinetics , organic chemistry , physics , quantum mechanics , adsorption
A new method of measuring equilibrium constants of proton transfer gas phase reactions is proposed. The method is based on measuring only the endothermic direction. The expression developed is: K k exp (BR) k c /{( k c k exp ) k ′ c }, where k exp is the measured rate constant, BR is the branching ratio of the proton transfer channel, k c and k ′ c are the forward and reverse collision rates. Two reaction systems were measured: the equilibrium between methanol and chloroacetonitrile and the equilibrium between ethanol and acetaldehyde. Both equilibrium constants were calculated by measuring forward end reverse rate constants and by the new method. There is good agreement between the two methods and with previously published values.