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1.
The rate constant for the reaction or NH3 + OH → NH2 + H2O has been measured in a high temperature fast flow reactor over the range 294–1075 K k = (5.41 ± 0.86) × 10-12 exp[?(2120 ± 143) cal mole?1/RT cm3 molecule?1 s?1. This result is compared with literature values and discussed. 相似文献
2.
Third order rate constants have been determined for the reaction O + SO2 + N2O → SO3 + N2O over the temperature range 299–392 K using a modulation technique. The Arrhenius expression obtained is k2N2O = 3.32 × 1010 exp[?(2000±400)/RT] liter2 mole?2 s?1. This temperature dependence is in good agreement with recent flash photolysis-resonance fluorescence measurements using N2 as a third body. 相似文献
3.
The rate constants for the reactions C2O + H → products (1) and C2O + H2 → products (2) have been determined at room temperature by means of laser-induced fluorescence detection of C2O radicals, generated either by the KrF excimer laser photolysis Of C3O2, or by the reaction of C3O2 with O atoms. Values of k1 = (3.7 ± 1.0) × 10?11 cm3 s?1 and k2 = (7 ± 3) × 10?13 cm3 s?1 were obtained. 相似文献
4.
Absolute rate constants for the reaction of O(3P) atoms with n-butane (k2) and NO(M Ar)(k3) have been determined over the temperature range 298–439 K using a flash photolysis-NO2 chemiluminescence technique. The Arrhenius expressions obtained were k2 = 2.5 × 10?11exp[-(4170 ± 300)/RT] cm3 molecule?1 s?1, k3 = 1.46 × 10?32 exp[940 ± 200)/ RT] cm6 molecule?2 s?1, with rate constants at room temperature of k2 = (2.2 ± 0.4) × 10?14 cm3 molecule?1 s?1 and k3 = (7.04 ± 0.70)×10?32 cm6 molecule?2 s?1. These rate constants are compared and discussed with literature values. 相似文献
5.
Absolute rate constants are measured for the reactions: OH + CH2O, over the temperature range 296–576 K and for OH + 1,3,5-trioxane over the range 292–597 K. The technique employed is laser photolysis of H2O2 or HNO3 to produce OH, and laser-induced fluorescence to directly monitor the relative OH concentration. The results fit the following Arrhenius equations: k (CH2O) = (1.66 ± 0.20) × 10?11 exp[?(170 ± 80)/RT] cm3 s?1 and k(1,3,5-trioxane) = (1.36 ± 0.20) × 10?11 exp[?(460 ± 100)/RT] cm3 s?1. The transition-state theory is employed to model the OH + CH2O reaction and extrapolate into the combustion regime. The calculated result covering 300 to 2500 K can be represented by the equation: k(CH2O) = 1.2 × 10?18 T2.46 exp(970/RT) cm3 s?1. An estimate of 91 ± 2 kcal/mol is obtained for the first C? H bond in 1,3,5-trioxane by using a correlation of C? H bond strength with measured activation energies. 相似文献
6.
The rate constant for the reaction NH3 + OH → NH2 + H2O was determined by the comparison of the calculated induction period data with experiments by the shock tube technique in the range 1360–1840 K, for NH3-H2-O2-Ar mixtures. The rate constants can be represented by the expression k = 1012.49±0.04exp[(?1.95±0.15) kcal/,RT] cm3 mol?1 s?1. 相似文献
7.
Experimental differential cross sections for 40 keV electrons scattered by C2H2, C2H4 and C2H6 molecules were measured using the gas electron diffraction method in the range of the scattering variable s from s = 1 A?1 to s = 30 A?1. The differential cross sections for neon were also measured and compared with calculated differential cross sections to calibrate the diffractograph. Experimental differential cross sections show significant deviations with respect to theoretical differential cross sections calculated from the Debye-Ehrenfest model, mainly in the range of small scattering angles. The observed differences are connected to chemical binding effects. From the experimental data, an estimation of the binding energy was carried out. The deduced values: ?0.58 ± 0.20 au for C2H2, ?0.94 ± 0.30 au for C2H4 and ?1.23 ± 0.40 au for C2H6 are in agreement with those obtained by thermochemical methods. 相似文献
8.
The laser flash photolysis of ozone at ≈ 6000 Å has been used to generate a clean kinetic source of ground state atomic oxygen, O(3P). The decay of O(3P) due to reaction with O3 was monitored via resonance fluorescence at 1300 Å, under static reaction cell conditions. Over the temperature range of 220–353°K, the bimolecular rate constant, k1, could be expressed in Arrhenius form as: k1 = (2.02 ± 0.19) × 10?11 exp[-(4522 ± 210 kcal/mole)/RT]. Units are in cm3molec?1 sec-1. A comparison of the results from this work with other recent investigations, indicates that the reliability of k1 is now probably as good as 10–15% over nearly 300 degrees. 相似文献
9.
The kinetics of C6H5 reactions with n‐CnH2n+2 (n = 3, 4, 6, 8) have been studied by the pulsed laser photolysis/mass spectrometric method using C6H5COCH3 as the phenyl precursor at temperatures between 494 and 1051 K. The rate constants were determined by kinetic modeling of the absolute yields of C6H6 at each temperature. Another major product C6H5CH3 formed by the recombination of C6H5 and CH3 could also be quantitatively modeled using the known rate constant for the reaction. A weighted least‐squares analysis of the four sets of data gave k (C3H8) = (1.96 ± 0.15) × 1011 exp[?(1938 ± 56)/T], and k (n‐C4H10) = (2.65 ± 0.23) × 1011 exp[?(1950 ± 55)/T] k (n‐C6H14) = (4.56 ± 0.21) × 1011 exp[?(1735 ± 55)/T], and k (n?C8H18) = (4.31 ± 0.39) × 1011 exp[?(1415 ± 65)T] cm3 mol?1 s?1 for the temperature range studied. For the butane and hexane reactions, we have also applied the CRDS technique to extend our temperature range down to 297 K; the results obtained by the decay of C6H5 with CRDS agree fully with those determined by absolute product yield measurements with PLP/MS. Weighted least‐squares analyses of these two sets of data gave rise to k (n?C4H10) = (2.70 ± 0.15) × 1011 exp[?(1880 ± 127)/T] and k (n?C6H14) = (4.81 ± 0.30) × 1011 exp[?(1780 ± 133)/T] cm3 mol?1 s?1 for the temperature range 297‐‐1046 K. From the absolute rate constants for the two larger molecular reactions (C6H5 + n‐C6H14 and n‐C8H18), we derived the rate constant for H‐abstraction from a secondary C? H bond, ks?CH = (4.19 ± 0.24) × 1010 exp[?(1770 ± 48)/T] cm3 mol?1 s?1. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 49–56, 2004 相似文献
10.
Dissociation rates of SO2 in SO2 + Ar mixtures at 6%, 11%, 15% and 20% of SO2 were measured behind incident shock waves over a temperature range 4000–6000 K at initial pressures 1.0 to 2.5 Torr. The recorded laser schlieren signals exhibited two exponentials, the faster one due to vibrational relaxation and the slower one due to dissociation. The initial dissociation rate was calculated from the value of the density gradient at the point of intersection of the two exponentials. A least-squares analysis of the experimental data yielded the following empirical relations: kSO2Ar = 3.34 × 1015 exp(?107.6 kcal mole?1/RT) cm3/mole s, kSO2SO2 = 5.02 × 1014 exp(?66.6 kcal mole?1 kcal mole?1/RT) cm3/mole s. 相似文献
11.
The rate constant of the reaction OH + HCl → H2O + Cl was measured in a flow tube over the temperature range 224 to 460°K using resonance fluorescence detection of OH. An Arrhenius expression k1 = (2.0 ± 0.1) × 10?12 exp [?(620 ± 20 cal/mole)/RT] was obtained. Stratospheric and reaction kinetic implications are discussed briefly. 相似文献
12.
Michael J. Kurylo 《Chemical physics letters》1973,23(4):467-471
The rate constants for the reactions OH(X2Π, ν = O) + NH3 → k1 H2O + NH2 and OH(X2Π, ν = O) + O3k2 → HO2 + O2 were measured at 298°K by the flash photolysis resonance fluorescence technique. The values of the rate constants thus obtained are K1 = (4.1 ± 0.6) × 10?14 and k2 = (6.5 ± 1.0) × 10?14 in units of cm3 molecule ?1 sec1. The results are discussed in terms of understanding the dynamics of the perturbed stratosphere. 相似文献
13.
The rate constant for the reaction of ozone with nitrogen dioxide has been measured over the temperature range 259 to 362°K, using a stopped-flow system coupled to a beam sampling mass spectrometer. A fit of the data to the Arrhenius equation gave: k = (9.44 ± 2.46) × 1010 exp[(?2509 ± 76)/T] cm3 mol?1 sec?1. 相似文献
14.
Flash photolysis of NO coupled with time resolved detection of O via resonance fluorescence has been used to obtain rate constants for the reaction O + NO + N2 → NO2 + N2 at temperatures from 217 to 500 K. The measured rate constants obey the Arrhenius equation k = (15.5 ± 2.0) × 10?33 exp(1160 ± 70)/1.987 T] cm6 molecule?2 s?1. An equally acceptable equation describing the temperature dependence of k is k = 3.80 × 10?27/T1.82 cm6 molecule?2 s?1. These results are discussed and compared with previous work. 相似文献
15.
Rate coefficients for collisional removal of O(1D) by six atmospheric gases have been measured by monitoring the appearance of O(3P) following photolytic production of O(1D). The measured values, kM±2σ, in units of 10?11 cm?3 molecule ?1 s?1 are kO3 = 22.8±2.3, kN2 = 2.52 ± 0.25, kCO2 = 10.4 ± 1.0,kH2O 195± 2.0, kN2O = 11.7 ± 1.2, and kH2, = 11.8±1.2. 相似文献
16.
The reaction kinetics of NH2 with propylene is studied by flash photolysis in the temperature range 300-500K. The NH2 radicals are detected by resonance absorption, using a cw single mode dye laser. This method allows the detection of very small radical concentrations in a wide range of experimental conditions. The reaction of NH2 with propylene is fairly slow and seems to correspond to the addition process. The Arrhenius expression obtained is (E in kcal/mole):k(NH2 + C3H6) = 2.9 × 108 exp[-4.3(± 0.2)[RT]M?1s?1. 相似文献
17.
The kinetics of the reaction NH2 + NO → N2 + H2O were studied, using a conventional flash photolysis system. A value of k1 = (1.1 ± 0.2) × 1010 & mole?1 s?1 was obtained at room temperature and in the pressure range 2–700 torr in the presence of nitrogen. A slight negative temperature coefficient was observed between 300 and 500 K, equivalent to a negative activation energy of 1.05 ± 0.2 kcal mole?1. 相似文献
18.
The kinetics of the reactions of hydroxy radicals with cyclopropane and cyclobutane has been investigated in the temperature range of 298–492 K with laser flash photolysis/resonance fluorescence technique. The temperature dependence of the rate constants is given by k1 = (1.17 ± 0.15) × 10?16 T3/2 exp[?(1037 ± 87) kcal mol?1/RT] cm3 molecule?1 s1 and k2 = (5.06 ± 0.57) × 10?16 T3/2 exp[?(228 ± 78) kcal mol?1/RT] cm3 molecule?1 s?1 for the reactions OH + cyclopropane → products (1) and OH + cyclobutane → products (2), respectively. Kinetic data available for OH + cycloalkane reactions were analyzed in terms of structure-reactivity correlations involving kinetic and energetic parameters. 相似文献
19.
合成了高氯酸镨和咪唑(C3H4N2), DL-α-丙氨酸(C3H7NO2)混配配合物晶体. 经傅立叶变换红外光谱、化学分析和元素分析确定其组成为[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3. 使用具有恒温环境的溶解-反应量热计, 以2.0 mol•L-1 HCl为量热溶剂, 在T=(298.150±0.001) K时测定出化学反应PrCl3•6H2O(s)+2C3H7NO2(s)+C3H4N2(s)+3NaClO4(s)=[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s)+3NaCl(s)+5H2O(1)的标准摩尔反应焓为ΔrHmө=(39.26±0.11) kJ•mol-1. 根据盖斯定律, 计算出配合物的标准摩尔生成焓为ΔfHmө{[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s), 298.150 K}=(-2424.2±3.3) kJ•mol-1. 采用TG-DTG技术研究了配合物在流动高纯氮气(99.99%)气氛中的非等温热分解动力学, 运用微分法(Achar-Brindley-sharp和Kissinger法)和积分法(Satava-Sestak和Coats-Redfern法)对非等温动力学数据进行分析, 求得分解反应的表观活化能E=108.9 kJ•mol-1, 动力学方程式为dα/dt=2(5.90×108/3)(1-α)[-ln(1-α)]-1exp(-108.9×103/RT). 相似文献
20.
Yoshiaki Hidaka Kazuyuki Kawanami Hiroyuki Kawano Masao Suga 《Chemical physics letters》1984,103(5):393-396
CF3ClH2 mixtures highly diluted with Ar were heated to 1400–1600 K behind reflected shock waves. The HCl emission was followed in order to determine the rate constant (k1) of the reaction, CF3Cl + M CF3 + Cl + M, and k1 = 2.1 × 1017 exp(?75000/RT) cm3 mol?1 s?1 was computed. 相似文献