激光诱导的温度跃迁测量中氮氧化物(N2O3)的缔合和解离动力学+ M =二氧化氮+一氧化二氮+ M体系
摘要:
The kinetics of the N2O3 + M = NO + NO2 + M reaction has been studied over a wide range of pressure by a laser-induced temperature jump relaxation method. Equilibrium mixtures at 225 K containing nitrogen dioxide, dinitrogen trioxide, dinitrogen tetroxide, nitric oxide, a small quantity of SiF4 as an IR absorber, and an excess of argon as a third-body gas collider are rapidly heated by a short pulse Of CO2 laser radiation. The induced temperature jump, between 0.5 and 3 K, displaces the equilibrium toward NO2 and NO formation. The rate of relaxation to the new equilibrium concentrations at higher temperature is monitored by observing spectroscopically the time dependence of the N2O3 concentration in the UV. For small perturbations, simple mathematics relates the measured chemical relaxation time constant to the thermal rate constants of the N2O3 + M = NO + NO2 + M system. Experimental results, obtained in the 0.5-200 bar pressure range of argon corresponding to the third-order and falloff region of the reaction have been fitted by falloff curves established according to a method developed by Troe. The following high- and low-pressure limiting rate constants for the NO + NO2 recombination at 227 K are extrapolated from the experimental data: k(rec,infinity) = (3.5 +/- 1.0) X 10(12) cm3 mol-1 s-1 and k(rec,o)/[Ar] = (1.0 +/- 0.5) X 10(15) CM3 Mol-1 s-1, respectively. These values lie within a factor of 2 of those that may be predicted using a simplified statistic adiabatic channel (SAC) model. The temperature dependence of the recombination rate constant, measured experimentally between 227 and 260 K, yields the following expressions for the high-pressure and the low-pressure limiting rate constants, respectively: k(rec,infinity)(T) = (1.6(+1.6/-0.5)) X 10(9)T(1.4+/-0.2)CM3 mol-1 s-1, and k(rec,o)(T)/[Ar] = (1.0(+1.0/-0.6)) X 10(33-T-(7.7+/-0.8) cm3 mol-1 s-1.
On the behaviour of nitrogen oxides in liquefied argon and krypton. Dimerisation of nitric oxide
作者:E.J. Sluyts、B.J. Van der Veken
DOI:10.1016/0022-2860(94)07975-7
日期:1994.4
Abstract Solutions containing several nitrogenoxide species have been investigated in liquefiedargon in the temperature range 84–105 K, and in liquefied kyrpton in the temperature range 116–150 K, using infrared spectroscopy. The following nitrogenoxide species were characterised in these solutions: NO, cis -ONNO, trans -ONNO, the asymmetric dimer ONON, asymmetric ONNO 2 , symmetric ONONO and N
摘要 已经使用红外光谱研究了在 84-105 K 温度范围内的液化氩气和 116-150 K 温度范围内的液化氪气中含有几种氮氧化物的溶液。在这些溶液中表征了以下氮氧化物种类:NO、顺式-ONNO、反式-ONNO、不对称二聚体ONON、不对称ONNO 2 、对称ONONO和具有D 2h 对称性的N 2 O 4 。NO 二聚化为顺式-ONNO 的焓已在液化氩气中测定为-14.3±1 kJ mol -1 。
Preparation of biphenyl compounds
申请人:Merck & Co., Inc.
公开号:US03992459A1
公开(公告)日:1976-11-16
Biaryl coupling, particularly to form 2,4-difluorobiphenyl, is accomplished by diazotizing an aniline and coupling the benzenediazonium salt with a second aromatic component in the presence of a strong acid, an inert finely divided solid and copper powder or a copper salt.
Mechanism of the Reaction of Olefins with Nitrous Anhydride (O═N–O–N═O) to Form 1,2-Oxazetes
作者:G. Sudhakar Reddy、E. J. Corey
DOI:10.1021/acs.orglett.2c04080
日期:2023.1.13
The mechanistic pathway for the formation of 1,2-oxazetes by reaction of olefins with nitrous anhydride has been clarified. The initial reaction intermediate, a β-nitroso nitrite ester that is sensitive to light, undergoes O–NO fission to form a β-nitroso alkoxy radical, even with ambient fluorescent lighting but much faster with blue light irradiation. The oxygen of the alkoxy radical subsequently