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Dediazoniation of Arenediazonium Ions in Homogeneous Solutions. Part XVII. Kinetics and mechanisms of dediazoniation of p ‐chlorobenzenediazonium tetrafluoroborate in weakly alkaline aqueous solutions in the presence of oxygen
Author(s) -
Besse Jacques,
Zollinger Heinrich
Publication year - 1981
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19810640217
Subject(s) - chemistry , catalysis , tetrafluoroborate , aqueous solution , inorganic chemistry , ionic strength , kinetics , ion , ionic bonding , oxygen , medicinal chemistry , photochemistry , organic chemistry , ionic liquid , physics , quantum mechanics
The kinetics of dediazoniation of p ‐chlorobenzenediazonium tetrafluoroborate have been studied in buffer solutions in the pH‐range 9.0–10.0, ionic strength I = 0.10, at 20.0° in glass and polytetrafluoroethylene vessels. The presence of oxygen (<5 ppb of O 2 , 60 to 100 ppb of O 2 , air, > 99% of O 2 ) has a decisive influence on the rate and kinetic order of the dediazoniation. Iodoacetic acid inhibits the reaction, whereas p ‐chlorophenol has a catalytic effect, and in air and >99% of O 2 it acts as an autocatalyst. The reaction is subject to general‐base catalysis by water, hydroxyl ions, hydrogen carbonate and carbonate ions. The kinetic results are interpreted in conjunction with data concerning the reaction products [2] and a 15 N‐CIDNP. investigation of a related system [3]. Specific radical chain mechanisms are consistent with the results.