Experimental and theoretical study of the mechanism for the kinetic of elimination of methyl carbazate in the gas phase
Experimental and theoretical study of the mechanism for the kinetic of elimination of methyl carbazate in the gas phase
复制标题
肼基甲酸甲酯气相消除动力学机理的实验与理论研究
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
G. Chuchani
中科院分区：
文献类型：
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作者：
A. Herize;J. Mora;Jesús Lezama;E. Márquez;Tania Córdova;G. Chuchani
在340-390 °C的温度范围和47-118托的压力范围内，在静态系统中测定肼基甲酸甲酯在气相中的消除动力学。该反应是均相的，单分子的，并且服从一级速率定律。分解产物是甲胺、亚硝酸和CO气体。速率系数随温度的变化可以用阿耳忒弥斯公式表示：log k1（s−1）=（11.56 ± 0.34）−（180.7 ± 4.1）kJ mol−1（2.303 RT）−1。在B3 LYP/6- 31 G（d，p）和MP2/6- 31 G（d，p）水平上，计算得到的动力学和热力学参数与实验值吻合较好.这些计算暗示了一个涉及协调非同步准三元环环状过渡态的分子机制，以得到一个不稳定的中间体，1，2-oxaziridin-3-one。键级分析和自然电荷分析表明，酯的O（烷基）C（烷基）键的极化是该反应的速率决定因素。版权所有© 2008约翰威利父子有限公司。
The elimination kinetic of methyl carbazate in the gas phase was determined in a static system over the temperature range of 340–390 °C and pressure range of 47–118 Torr. The reaction is homogeneous, unimolecular, and obeys a first order rate law. The decomposition products are methyl amine, nitrous acid, and CO gas. The variation of the rate coefficients with temperatures is given by the Arrhenius expression: log k1 (s−1) = (11.56 ± 0.34) − (180.7 ± 4.1) kJ mol−1(2.303 RT)−1. The estimated kinetics and thermodynamics parameters are in good agreement to the experimental values using B3LYP/6-31G (d,p), and MP2/6-31G (d,p) levels of theory. These calculations imply a molecular mechanism involving a concerted non-synchronous quasi three-membered ring cyclic transition state to give an unstable intermediate, 1,2-oxaziridin-3-one. Bond order analysis and natural charges implies that polarization of O (alkyl)C (alkyl) bond of the ester is rate determining in this reaction. Copyright © 2008 John Wiley & Sons, Ltd.