Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1979-11-28
pubmed:abstractText
The ionization kinetics of 1.3-diketone carbon acids are slow relative to those of classical acids and bases. The ionization kinetics of three 4'-substituted 2-phenyl-1,3-indandiones, 4'-chloro-, 4'-methoxy-, and 2-phenyl-1,3-indandione itself, were studied at 25 degrees and ionic strength 0.1 using stopped-flow spectrometry and a pH jump technique. A log k'obs-pH profile for the approach to the ionization equilibrium was consistent with a reaction scheme postulated earlier for the ionization of another carbon acid, phenylbutazone. The percent enol versus diketo form of the acids and the pKaenol and pKadiketo were calculated from the kinetic data. Hammett plots of the various kinetic and equilibrium constants supported a mechanism for acid deprotonation consistent with proton abstraction being the predominant process when very weak bases such as water were the proton acceptors. Desolvation effects and the work required to get the two reacting molecules together in the correct configurations predominated when the proton abstraction was by stronger proton acceptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-3549
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1047-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Kinetics and mechanism of ionization of the carbon acids 4'-substituted 2-phenyl-1,3-indandiones.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.