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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 35, Number 8
BKCSDE 35(8)
August 20, 2014 

 
Title
Solvolysis Reaction Kinetics, Rates and Mechanism for Phenyl N-Phenyl Phosphoramidochloridate
Author
Hojune Choi, Kiyull Yang, Han Joong Koh*, In Sun Koo*
Keywords
Phenyl N-phenyl phosphoramidochloridate, Extended Grunwald-Winstein equation, SN2 mechanism, Activation parameters
Abstract
The rate constants of solvolysis of phenyl N-phenyl phosphoramidochloridate (PhNHPO(Cl)OPh, Target Compound-TC1) have been determined by a conductivity method. The solvolysis rate constants of TC1 are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale and YCl solvent ionizing scale, and sensitivity values of 0.85 ± 0.14 and 0.53 ± 0.04 for l and m, respectively. These l and m values were similar to those obtained previously for the complex chemical substances dimethyl thiophosphorochloridate; N,N,N',N'-tetramethyldiamidophosphorochloridate; 2-phenyl-2-ketoethyl tosylate; diphenyl thiophosphinyl chloride; and 9-fluorenyl chloroformate. As with the five previously studied solvolyses, an SN2 pathway is proposed for the solvolyses of TC1. For four representative solvents, the rate constants were measured at several temperatures, and activation parameters (ΔH≠ and ΔS≠) were estimated. These activation parameters are also in line with the values expected for an SN2 reaction.
Page
2465 - 2470
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