A new method for monitoring dediazoniation reactions: Simultaneous monitoring of concentration and rates of product formation and loss of starting material for the dediazoniation ofp-methylbenzenediazonium tetrafluoroborate

Abstract

We have examined the kinetics and mechanism of the dediazoniation reaction of p-methylbenzenediazonium tetrafluoroborate in the presence and absence of CuCl 2 using a methodology developed by us that allows, simultaneously, and within the same experiment to identify, to quantify, and to obtain the rate constants for the formation of all dediazoniation products, and, indirectly, the rate constant for the diazonium salt decomposition. The methodology developed combines the use of coupling reactions, to form a stable azo dye, followed by analysis by HPLC.

Effects of emulsifier hydrophile–lipophile balance and emulsifier concentration on the distributions of gallic acid, propyl gallate, and α-tocopherol in corn oil emulsions

“…4-Hexadecylbenzenediazonium tetrafluoroborate, 16-ArN 2 BF 4 , was prepared in high yield and purity under nonaqueous conditions from commercial 4-hexadecylaniline (Aldrich, 97%) by diazotization following a published method [52,53] and stored in the dark at low temperature to minimize its decomposition.…”

Quantitative determination of α-tocopherol distribution in a tributyrin/Brij 30/water model food emulsion

“…All solutions were prepared with Milli-Q grade water. 16-ArN 2 BF 4 was prepared in high yield and purity from commercial 4-hexadecylaniline (Aldrich, 97%) by diazotization following a published method [28,35].…”

“…However, LSV may not work well in emulsions containing high volume fractions of oil [24][25][26] or if the electrochemical signal of the antioxidant overlaps with that of 16-ArN + 2 [27]. To overcome these limitations, we developed a derivatization method to determine k obs by trapping unreacted arenediazonium ion with a coupling reagent that rapidly forms a colored azo dye following prior work in aqueous and micellar solutions [28][29][30][31]. Here the Bratton-Marshall reagent (N -(1-naphthyl)ethylenediamine, NED, Scheme 2, was chosen as the coupling agent because it reacts rapidly with arenediazonium ions in acidic solutions [32] yielding a purple dye.…”

Effects of Ascorbic Acid on Arenediazonium Salts Reactivity: Kinetics and Mechanism of the Reaction

“…Chromatographic kinetic data for all dediazoniation products were obtained according to a well-established procedure [46] [47] by quenching the dediazoniation reaction at convenient times with an aliquot of an aq. stock soln.…”

“…8. Details of the method and the equations for converting HPLC peak areas (A) to concentration are reported elsewhere [46] [48]. Percent yields, Y, of the dediazoniation products were obtained from the ratio of the concentration of dediazoniation product to the initial concentration of diazonium salt (estimated by weight).…”