NISCAIR Online Periodicals Repository

NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR)  >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.47A [2008] >
IJC-A Vol.47A(01) [January 2008] >


Title: Kinetics and mechanism of amine-catalysed solvolysis of azlactone in water-dioxan mixtures
Authors: Ismail, Amel M
Issue Date: Jan-2008
Publisher: CSIR
Abstract: The effect of replacing solvent water by dioxan up to 50% v/v on the rate of catalytic-amine solvolysis of azlactone has been measured spectrophotometrically in the temperature range 40-60ºC. Addition of an organic solvent to water largely decreases the rate of ring- opening process. Such an effect was found to diminish in the region of lower relative permittivity. The reaction rate constants are analyzed and discussed in terms of solvent effect and nucleophilicity of amines. ΔG≠ gradually decreases as a function of increasing [water], due to a complex and quasi-mirror image compensation of ∆H≠ and ΔS≠. The variation of ΔH≠ versus ΔS≠ is linear. The catalytic coefficient, kAm, for amine has been estimated from the general linear equation, kobs= k o + kAm [Amine]. The binary solvent mixtures used give an unusual range of properties. The plot of log kAm versus log [H₂O] show two linear segments with intersection at 33.3 mol dm⁻³[H₂O]. The correlation between log kAm and reciprocal of the relative permittivity is non-linear, while that between log kAm versus pKa is linear. All these observations are consistent with the suggested mechanism.
Page(s): 49-54
ISSN: 0376-4710
Source:IJC-A Vol.47A(01) [January 2008]

Files in This Item:

File Description SizeFormat
IJCA 47A(1) (2008) 49-54.pdf154.52 kBAdobe PDFView/Open
 Current Page Visits: 687 
Recommend this item

 

National Knowledge Resources Consortium |  NISCAIR Website |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2012 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 639369 since 06-Feb-2009  Last updated on 15-Dec-2014Webmaster: nopr@niscair.res.in