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Kinetics and reaction mechanism for alkaline hydrolysis of Y-substituted-phenyl diphenylphosphinates

Title
Kinetics and reaction mechanism for alkaline hydrolysis of Y-substituted-phenyl diphenylphosphinates
Authors
Hong H.-J.Lee J.Bae A.R.Um I.-H.
Ewha Authors
엄익환
SCOPUS Author ID
엄익환scopusscopus
Issue Date
2013
Journal Title
Bulletin of the Korean Chemical Society
ISSN
0253-2964JCR Link
Citation
vol. 34, no. 7, pp. 2001 - 2005
Indexed
SCI; SCIE; SCOPUS; KCI WOS scopus
Abstract
The second-order rate constants (kOH-) for the reactions of Y-substituted-phenyl diphenylphosphinates (4a-4i) with OH- in H 2O at 25.0 ± 0.1 °C have been measured spectrophotometrically. Comparison of kOH- with kEtO- (the second-order rate constants for the corresponding reactions with E tO- in ethanol) has revealed that EtO- is less reactive than OH- although the former is ca. 3.4 pKa units more basic than the latter, indicating that the reactivity of these nucleophiles is not governed by their basicity alone. The Brønsted-type plot for the reactions of 4a-4i with OH- is linear with βlg = -0.36. The Hammett plot correlated with σ- constants results in a slightly better correlation than that correlated with σo constants but exhibits many scattered points. In contrast, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ρ = 0.95 and r = 0.55. The r value of 0.55 implies that a negative charge develops partially on the O atom of the leaving group. Thus, the reactions of 4a-4i with OH- have been concluded to proceed through a concerted mechanism. Copyright © 2005 KCSNET.
DOI
10.5012/bkcs.2013.34.7.2001
Appears in Collections:
자연과학대학 > 화학·나노과학전공 > Journal papers
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