15499-23-7Relevant articles and documents
Endothermic formation of a chemical bond by entropic stabilization: Difluoronitroxide radical in solid argon
Misochko, Eugenii Ya.,Akimov, Alexander V.,Goldschleger, Ilya U.,Boldyrev, Alexander I.,Wight, Charles A.
, p. 405 - 410 (2007/10/03)
Difluoronitroxide radical (F2NO) has been formed in solid argon matrices by successive addition of two diffusing F atoms to NO. This radical exists in dynamic equilibrium with a van der Waals complex (FFNO). Measurements of the equilibrium concentrations as a function of temperature show that the changes in enthalpy and the entropy associated with formation of the F2NO radical are ΔH = 1240 ± 180 J/mol and ΔS = 62 ± 10 J/(mol K). Because both these quantities are positive, the equilibrium favors F2NO only at elevated temperatures. This situation is a rare case in which formation of a chemical bond is stabilized only by an increase in the entropy of the system.
A Gasphase Kinetic Investigation of the System F = HNO3 and the Determination of Absolute Rate Constants for the Reaction of the NO3 Radical with CH3SH, 2-Methylpropene, 1,3-Butadiene and 2,3-Dimethyl-2-Butene
Rahman, M. M.,Becker, E.,Benter, Th.,Schindler, R. N.
, p. 91 - 100 (2007/10/02)
The reaction of HNO3 with atomic fluorine (1) has been studied in a discharge-flow system at 298 K.Mass spectrometric detection with single ion counting was employed.The rate constant for the primary reaction (1) at 298 K has been determined from the rate of HF and NO3 formation under conditions 0 and the rate of HNO3-removal under conditions 0 F + HNO3 --> HF + NO3 k(1)=(2.1 +/- 1)E-11cm3s-1. (1) From the patterns of growth and decay of the primary product NO3 and the secondary product FO under various ratios of the initial concentrations of the reactants, the rate constants of the following secondary reactions have been determined: F + NO3 --> FO + NO2 k(2)=3E1 cm s (2) FO + NO3 --> FO2 + NO2 k(3)=1E-12 cm3s-1. (3) Further, the rate constants for the reactions of NO3 with CH3SH, 2-methylpropene, 1,3-butadiene and 2,3-dimethyl-2-butene at 298 K have been determined by introducing these reactants into the flow system and measuring their consumption under pseudo-first-order conditions.The values of the rate constants obtained are 7.7 +/- 0.5, 3.3 +/- 0.5, 1.7 +/- 0.3 and 384 +/- 38 in units of E-13 cm3s-1 respectively.A comparison is made between the values determined in this work and those reported in the literature. - Key words: Chemical Kinetics / Mass Spectrometry / Radicals
