Kinetics of Thermal Decomposition of 4-Carboxyl-2,6-Dinitrobenzenediazonium Ion (CDNBD)
Abstract:The kinetics of thermal decomposition of 4-carboxyl-2,6-dinitrobenzenediazonium ion (CDNBD), an arenediazonium ion newly developed as a derivatizing reagent for drug analysis, are described. The arenediazonium ion, in an optimized concentrated sulfuric acid/orthophosphoric acid medium, was incubated for various time intervals at 30°, 45°, 55°, 65°, 75°, and 85°C. The amount of ion left after each time interval was quantified selectively by colorimetric assay at 490 nm, using mefenamic acid as a model diazo-coupling component. The rate constants for the decomposition were determined graphically. An Arrhenius plot was used to delineate the dependence of the rate constant on temperature and to predict the half-life at 25°C and lower temperatures. The diazonium ion decomposed by first-order kinetics. The rate constants of decomposition, which increased progressively with temperature, were 3.18 ± 0.41 × 10−5, 1.19 ± 0.07 × 10−4, 4.87 ± 0.15 × 10−4, 12.88 ± 0.73 × 10−4, and 21.32 ± 2.74 × 10−4 (s−1) with corresponding half-lives of 363, 97.06, 23.72, 8.97, and 5.42 min at 30°, 45°, 55°, 65°, and 75°C, respectively. CDNBD is highly stable in concentrated acid medium, with half-life values of about 10 h, 10 days, and 7.3 months at 25°, 0°, and −20°C, respectively. The reagent stability profile shows that it could be readily adapted for routine applications in instrumental chemical analysis.
Document Type: Research Article
Publication date: 2005-07-01
More about this publication?
- The Journal of AOAC INTERNATIONAL publishes refereed papers and reviews in the fields of chemical, biological and toxicological analytical chemistry for the purpose of showcasing the most precise, accurate and sensitive methods for analysis of foods, food additives, supplements and contaminants, cosmetics, drugs, toxins, hazardous substances, pesticides, feeds, fertilizers and the environment available at that point in time. The scope of the Journal includes unpublished original research describing new analytical methods, techniques and applications; improved approaches to sampling, both in the field and the laboratory; better methods of preparing samples for analysis; collaborative studies substantiating the performance of a given method; statistical techniques for evaluating data. The Journal will also publish other articles of general interest to its audience, e.g., technical communications; cautionary notes; comments on techniques, apparatus, and reagents.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Information for Advertisers
- Journal Information
- Ingenta Connect is not responsible for the content or availability of external websites