Control of Chain Reactions by Use of Laser Irradiation - One-step Methanol Synthesis from Methane -

激光灯是非常单色的，而且有时在一个非常短的脉冲中具有强大的动力，因此，希望在化学合成和其他相关过程中使用有效的链反应，在当前的调查中，甲烷的一步合成，以及甲醇/空气混合气体的激光点火已经从上方观察点研究过。在对甲醇、甲烷、O_2和N_2O （如有效的激光光吸收器）的一步合成的实验调查中，将甲醇引入一个温度可控的反应细胞，并在193纳米处通过ArF模拟器激光光辐射。reaction temperature was room temperature - 300 C， and the pressure， 300 - 600 Torr。该产品含有氧化物-包括甲醇、C_2-C_3氢化合物如CO和CO_2甲烷转化和甲醇在O_2中的含量增加的选择，是指在甲醇合成中存在的氧化物链反应。“预混合甲醇/空气混合物的点火是在矩形喷嘴燃烧器上进行的，而成功点火的必要激光通量则被确定为预混合气体的均衡率的一个功能。”该结果是通过使用计算机模拟进行分析的。它包括一个激光点火是由热力和激进物种的相似产生特征的。目前的研究清楚地显示了激光控制链反应在各种过程中的可能性的两个例子。

The laser light is very monochromatic, powerful and sometimes in a very short pulse, which is expected to be used in order to control effectively chain reactions in chemical syntheses and some other related processes.In the present investigation, one-step synthesis of methanol from methane, and laser ignition of methanol/air premixed gases have been studied from the above view point.1. In the experimental investigation of one-step synthesis of methanol from methane, methane, O_2 and N_2O (as an effective laser light absorber) were introduced into a temperature-controllable reaction cell and were irradiated by ArF eximer laser light at 193 nm. The reaction temperature was room temperature - 300゜C, and the pressure, 300 - 600 Torr. The products were oxygen-containing species including methanol, C_2-C_3 hydrocarbons as well as CO and CO_2 Tthe methane conversion and the selectivity of methanol increased in the presence of O_2, which indicated the existence of oxidative chain reactions in favor of methanol synthesis.2. The ignition of premixed methanol/air mixtures was performed on a rectangular nozzle burner, and the necessary laser fluence for the successful ignition was determined as a function of equivalence ratio of the premixed gases. The results were analysed by use of a computer simulation. It was concluded that the laser ignition was characterized by simultaneous production of heat and radical species.The above two examples in the present research clearly showed the possibility of laser control of chain reactions in various processes.