Issue 15, 1974
From the journal:

Journal of the Chemical Society, Perkin Transactions 2

Urea synthesis from amines and cyanic acid: kinetic evidence for a zwitterionic intermediate

Andrew Williams  and  William P. Jencks  

Abstract

The following evdence supports the conclusion that the reaction of amines with cyanic acid and the hydrolysis of urea occur through a stepwise mechanism with the formation of an intermediate zwitterion. (1) The Brønsted type plot of log10k′versus ammonium ion pKa has a slope βnue 0·3 for basic amines and exhibits a break to a slope βnue 0·8 for weakly basic amines; the two segments are assigned to rate-determining nucleophilic attack and protontransfer steps, respectively. (2) General acid-base catalysis is observed only with weakly basic amines, for which the proton-transfer step is rate determining. (3) A change in rate-determining step with increasing buffer concentration is observed as the uncatalysed attack step becomes rate determining.

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Article information

DOI
https://doi.org/10.1039/P29740001753
Article type
Paper

J. Chem. Soc., Perkin Trans. 2, 1974, 1753-1759

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Urea synthesis from amines and cyanic acid: kinetic evidence for a zwitterionic intermediate

A. Williams and W. P. Jencks, J. Chem. Soc., Perkin Trans. 2, 1974, 1753 DOI: 10.1039/P29740001753

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