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首页> 外文学位 >Perturbation studies of moist carbon monoxide oxidation by chlorinated compounds: Hydrogen chloride and chloromethanes.
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Perturbation studies of moist carbon monoxide oxidation by chlorinated compounds: Hydrogen chloride and chloromethanes.

机译：潮湿的一氧化碳被氯化物（氯化氢和氯甲烷）氧化的扰动研究。

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A unique approach is used for studying the chemistry describing the post flame regions of toxic waste incinerators. The technique consists of perturbing the moist CO oxidation system with trace amounts of halogenated species: HCl, CH{dollar}sb3{dollar}Cl, CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar}, CHCl{dollar}sb3{dollar}, or CCl{dollar}sb4{dollar}. These reaction systems provide fundamental kinetic information and approximate the post flame chemistry. The experiments are performed between 1000 and 1150 K in a turbulent flow reactor at atmospheric pressure. The initial reaction bath compositions are approximately 1% mole fraction of CO, O{dollar}sb2{dollar}, and H{dollar}sb2{dollar}O, in nitrogen, with 100 ppm of chlorinated species. Temperature and stable species profiles are obtained and compared to numerical predictions to verify the accuracy of detailed kinetic mechanisms, and to identify controlling reactions.; A thorough understanding of the kinetics of the CO/H{dollar}sb2{dollar}O/O{dollar}sb2{dollar} reaction bath system are necessary to properly interpret the perturbation experiments. At 1000 K, the addition of O{dollar}sb2{dollar} is observed here to counter-intuitively inhibit the oxidation rate of CO. At these temperatures, this newly identified phenomenon is associated with the HO{dollar}sb2{dollar} chemistry, and results from a shift in its consumption via a chain propopagating to a chain terminating reaction.; Modeling of the perturbation experiments with HCl reveal that the reactions controlling the observed inhibition differ from those reported in earlier studies. The chain terminating reaction {dollar}Cl + HOsb2 to HCl + Osb2{dollar} is a major source of inhibition, while the radical recombination reactions {dollar}H + Cl + M to HCl + M{dollar} and {dollar}Cl + Cl + M to Clsb2 + M{dollar} are not the dominant sources of inhibition, due to the low Cl/H ratios.; The chloromethanes are extremely effective inhibitors due to the fast radical scavenging reactions: {dollar}RHCl + X to cdot RH + XCl{dollar} and {dollar}RHCl + Xtocdot RCl + XH,{dollar} where X is an O, H or OH radical. In comparison, HCl is a much less effective inhibitor. The effectiveness ranking of the chloromethanes as inhibitors is CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar} {dollar}>{dollar} CH{dollar}sb3{dollar}Cl {dollar}>{dollar} CCl{dollar}sb4{dollar} {dollar}>{dollar} CHCl{dollar}sb3{dollar} {dollar}>{dollar} HCl, based on mole fractions. This ranking correlates with the relative rates of the scavenging reactions. Chloroform is an exception, and is least inhibitive due to its rapid HCl elimination reaction. The main hydrocarbon radicals ({dollar}cdot{dollar}RCl and {dollar}cdot{dollar}RH) are responsible for the production of many identified intermediate species. Of particular importance are the unexpectedly high yields ({dollar}sim{dollar}10 to 30%) of the very toxic phosgene observed for all chloromethanes except CH{dollar}sb3{dollar}Cl.
机译：一种独特的方法用于研究描述有毒废物焚化炉火焰后区域的化学反应。该技术包括用少量的卤化物质干扰潮湿的CO氧化系统：HCl，CH {美元} sb3 {美元} Cl，CH {美元} sb2 {美元} Cl {美元} sb2 {美元}，CHCl {美元} sb3 {dollar}或CCl {dollar} sb4 {dollar}。这些反应系统提供基本的动力学信息并近似火焰后化学反应。实验是在大气压下的湍流反应器中于1000和1150 K之间进行的。初始反应浴的组成是在氮气中含100 ppm氯化物的CO，O，sb2，和O的摩尔分数约为1％。获得温度和稳定的物种分布，并将其与数值预测进行比较，以验证详细动力学机制的准确性，并确定控制反应。对CO / H {sb2 {dollar} O / O {sol2sb2 {dollar}）反应浴系统动力学的透彻理解对于正确地解释扰动实验是必要的。在1000 K处，观察到O {dollarssb2 {dollar}的添加会反直觉地抑制CO的氧化速率。在这些温度下，这一新发现的现象与HO {dollar} sb2 {dollar}化学有关，并且是由于其消耗的变化（通过链扩散和链终止反应）导致的。用HCl进行扰动实验的模型表明，控制所观察到的抑制作用的反应与早期研究中报道的反应不同。终止链的反应{美元} Cl + HOsb2对HCl + Osb2 {美元}是抑制作用的主要来源，而自由基重组反应{美元} H + Cl + M对HCl + M {美元}和{美元} Cl + Cl + M至Clsb2 + M {dollar}不是主要的抑制源，因为Cl / H比率低。由于快速的自由基清除反应，氯甲烷是极有效的抑制剂：{ROL美元的RHCl + X到Cdot RH + XCl的美元{美元}和{RHC美元的RHCl + Xtocdot RCl + XH的美元，{美元}其中X是O，H或OH基。相比之下，HCl是一种效果较差的抑制剂。氯甲烷作为抑制剂的有效性等级为CH {dollar} sb2 {dollar} Cl {dollar} sb2 {dollar} {dollar}> {dollar} CH {dollar} sb3 {dollar} Cl {dollar}> {dollar} CCl {美元sb4 {美元} {美元}> {美元} CHCl {美元} sb3 {美元} {美元}> {美元} HCl，基于摩尔分数。该等级与清除反应的相对速率相关。氯仿是一个例外，由于其快速的HCl消除反应，抑制性最小。主要的烃基（{cold {dollar} RCl和{cold {dollar} RH}}负责产生许多已确定的中间物种。尤为重要的是，对于除CH {dollar} sb3 {dollar} Cl以外的所有氯甲烷，观察到的剧毒光气的出乎意料的高产率（{dollar} sim {dollar} 10％至30％）。

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