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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Products and Mechanism of the Reaction of Cl with Butanone in N_2/O_2 Diluent at 297-526 K
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Products and Mechanism of the Reaction of Cl with Butanone in N_2/O_2 Diluent at 297-526 K

机译：Cl与丁酮在N_2 / O_2稀释剂中297-526 K反应的产物及机理

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The products, kinetics, and mechanism of the reaction Cl + butanone have been measured by UV irradiation of Cl2/butanone/N2 (O2) mixtures using either GC or FTIR analysis. In the absence of O2, the products are 1-,3-, and 4-chlorobutanone with yields of 3.1%, 76%, and 22.5%, respectively. As the temperature is increased,the yields of 1- and 4-chlorobutanone increase relative to the 3-chlorobutanone yield. On the basis of these increases, the activation energies for hydrogen abstraction at the 1 and 4 positions are determined to be 1800((300) and 470 (+300, -150) cal mol-1 relative to abstraction at the 3 position. In the presence of 400 ppm of O2 with 700-900 ppm of Cl2 at 297 K, the yields of 1- and 3-chlorobutanone decrease dramatically from 3.1% to 0.25% and from 76% to 2%, respectively, while the 4-chlorobutanone decreases only slightly from 22.5% to 18.5%. The observed oxygenated species are acetaldehyde (52%), butanedione (11%), and propionyl chloride (2.5%). Increasing the temperature to 400 K (O2 ) 500 ppm) suppresses these oxygenated products and 1- and 3-chlorobutanone again become the primary products, indicating that the O2 addition reaction to the 1- and 3-butanonyl radicals is becoming reversible. At 500 K and very high O2 mole fraction (170 000 ppm), a new product channel opens which forms a substantial yield (-20%) of methylvinylketone. Computer modeling of the product yields has been performed to gain an understanding of the overall reaction mechanism in the presence and absence of O2. The reaction of chlorine atoms with butanone proceeds with a rate constant of 4.0 ((0.4) 10-11 cm3 molecule-1 s-1 independent of temperature over the range 297-475 K (Ea ) 0 (200 cal mol-1). Rate constant ratios of k(CH2C(O)C2H5 + Cl2)/k(CH2C(O)C2H5 + O2) ) 0.027 ( 0.008,k(CH3C(O)CHCH3 + Cl2)/ k(CH3C(O)CHCH3 + O2) ) 0.0113 ( 0.0011, and k(CH3C(O)CH2CH2 + Cl2)/k(CH3C(O)CH2CH2 + O2) ) 1.52 ( 0.32 were determined at 297 K in 800-950 Torr of N2 diluent. In 700-900 Torr of N2/O2 diluent, the major fate of the alkoxy radicals CH3C(O)CH(O)CH3 and OCH2C(O)C2H5is decomposition to give CH3C(O) radicals and CH3CHO and HCHO and C(O)C2H5 radicals, respectively.
机译：Cl +丁酮反应的产物，动力学和机理已使用GC或FTIR分析通过对Cl2 /丁酮/ N2（O2）混合物进行紫外线照射来测量。在没有氧气的情况下，产物是1-，3-和4-氯丁酮，产率分别为3.1％，76％和22.5％。随着温度升高，相对于3-氯丁酮的产率，1-氯丁酮和4-氯丁酮的产率增加。在这些增加的基础上，相对于3位的提取，在1和4位取氢的活化能被确定为1800（（300）和470（+300，-150）cal mol-1。在297 K下存在400 ppm O2和700-900 ppm Cl2的情况下，1-和3-氯丁酮的收率分别从3.1％急剧下降至0.25％和从76％下降至2％，而4-氯丁酮从22.5％降至18.5％略有降低。观察到的含氧物质为乙醛（52％），丁二酮（11％）和丙酰氯（2.5％）。将温度升高至400 K（O2）500 ppm）抑制了这些氧合产物和1-和3-氯丁酮再次成为主要产物，表明O 2加到1-和3-丁酮基的反应是可逆的。在500 K和非常高的O2摩尔分数（170 000 ppm）下，打开了一条新的产品通道，形成了可观的产量（-20％）的甲基乙烯基酮。已经进行了产物收率的计算机建模以了解在存在和不存在O 2的情况下的总体反应机理。氯原子与丁酮的反应速率常数为4.0（（0.4）10-11 cm3分子-1 s-1，在297-475 K（Ea）0（200 cal mol-1）范围内与温度无关。 k（CH2C（O）C2H5 + Cl2）/ k（CH2C（O）C2H5 + O2）的速率常数比率）0.027（0.008，k（CH3C（O）CHCH3 + Cl2）/ k（CH3C（O）CHCH3 + O2 ））0.0113（0.0011，和k（CH3C（O）CH2CH2 + Cl2）/ k（CH3C（O）CH2CH2 + O2））1.52（0.32是在297 K下在800-950托的N2稀释剂中确定的。在700-900中将N2 / O2稀释剂的Torr，烷氧基CH3C（O）CH（O）CH3和OCH2C（O）C2H5的主要命运分解，分别得到CH3C（O）和CH3CHO和HCHO和C（O）C2H5自由基。

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