ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
4,2-Chloronitrobenzenediazonium ions in aqueous buffer solutions between pH 2.9 and 7.9 do not hydrolyze by dediazoniation as previous authors have assumed, but by denitration. The isomeric 2,4-compound reacts by denitration (ca. 70%) and dechlorination (ca. 30%). The reactions are general base catalyzed. The products and kinetics are consistent with an SNAr-mechanism in which the general base-catalyzed addition of a hydroxyl group at the reacting C-atom is rate-limiting. The rate maxima at or near the pH-values corresponding to (pK1 + pK2)/2 of the diazonium ⇄ cis-diazotate equilibria can be rationalized on the assumption that the diazonium ion is the only equilibrium form of the diazo compound which enters the substitution proper, and the superposition of the rate term B∑kB[B] of all nucleophiles involved (H2O, OH- and buffer bases).
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19810640607
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