The effect of basicity on fluorodenitration reactions using tetramethylammonium salts
作者:Dave J Adams、James H Clark、David J Nightingale
DOI:10.1016/s0040-4020(99)00409-3
日期:1999.6
The fluorodenitration of several nitroaromatics with tetramethylammonium salts has been found to be dependent on the basicity of the fluorinating species. Tetramethylammonium fluoride is highly basic and is capable of inducing H-D exchange in 1,3-dinitrobenzene, as well as deprotonating N,N-dimethylacetamide. Reaction of the fluoride with phthalic anhydride forms the bifluoride in situ. Tetramethylammonium
Decomposition kinetics of peroxynitrite: influence of pH and buffer
作者:Christian Molina、Reinhard Kissner、Willem H. Koppenol
DOI:10.1039/c3dt50945a
日期:——
The decay of ONOOH near neutral pH has been examined as a function of isomerization to H+ and NO3−, and decomposition to NO2− and O2via O2NOO−. We find that in phosphate buffer kisomerization = 1.11 ± 0.01 s−1 and kdisproportionation = (1.3 ± 0.1) × 103 M−1 s−1 at 25 °C and I = 0.2 M. In the presence of 0.1 M tris(hydroxymethyl)aminomethane (Tris), the decay proceeds more rapidly: kdisproportionation = 9 × 103 M−1 s−1. The measured first half-life of the absorbance of peroxynitrite correlates with [Tris]0·([ONOO−]0 + [ONOOH]0)2, where the subscript 0 indicates initial concentrations; if this function exceeds 6.3 × 10−12 M3, then Tris significantly accelerates the decomposition of peroxynitrite.
Preventing Nitrite Contamination in Tetramethylammonium Peroxynitrite Solutions
作者:Petr Latal、Reinhard Kissner、D. Scott Bohle、Willem H. Koppenol
DOI:10.1021/ic049161k
日期:2004.10.1
Peroxynitrite prepared from superoxide and nitric oxide in liquid ammonia does not contain detectable levels of nitrite. However, the dissolution of nitrite salts can lead to variable levels of peroxynitrite depending on the conditions used to disolve the salt. Low levels of nitrite result when frozen peroxynitrite solutions are first brought to +1 degreesC and then to room temperature. These undergo only 2-3% decomposition after 1 h, in contrast with the findings of a recent report (Lymar, S. V.; Khairutdinov, R. F.; Hurst, J.K. Inorg. Chem. 2003, 42, 5259-5266), where high levels of nitrite (similar to20%) result from rapid thawing of these solutions to room temperature. Warming the frozen peroxynitrite solution directly to room temperature in 30 min leads to a nitrite level of 28%.
Ray, P. C., Proceedings of the Chemical Society, London, <hi>1910</hi>, vol. 26, p. 172