THE THERMAL DECOMPOSITION OF DIETHYL ETHER .3. THE ACTION OF INHIBITORS AND THE MECHANISM OF THE REACTION
THE THERMAL DECOMPOSITION OF DIETHYL ETHER .3. THE ACTION OF INHIBITORS AND THE MECHANISM OF THE REACTION
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DOI：
10.1098/rspa.1958.0065
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发表时间：
1958-01-01
影响因子：
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通讯作者：
FREEMAN, GR
中科院分区：
文献类型：
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作者：
FREEMAN, GR
少量的一氧化氮可以将乙醚在525 °C下的热分解率降低到大约四分之一。更大的量加速分解，但是可以研究的“最大抑制”反应和“一氧化氮诱导”反应的浓度范围是如此广泛地分开，以至于这些反应可以被视为两个不同的实体。第三种反应是“不受抑制的”。记录所有三种的反应产物和动力学，并测量前两种的一氧化氮消耗。在所有三个主要产品是相同的，与次要的差异进行了讨论。在一氧化氮的存在下，会形成少量的氰化物和其他化合物。在一氧化氮诱导的反应中，每消耗一分子一氧化氮，就分解1.4个乙醚分子;在最大抑制反应中，取决于乙醚压力的比例要大得多。最大抑制反应的速率与一氧化氮或丙烯的浓度无关，并且对于两种抑制剂是相同的（如现在通过直接分析所证明的）。一级速率常数随醚的初始压力而变化，符合方程kinhib =（A[醚]）/（1 +B[醚]）+C[醚]。不受抑制的反应的速率常数随醚压而变化，其表达式虽然可能具有不同的代数形式，但在相当大的范围内与上述表达式在经验上相似。一氧化氮诱导的反应几乎是一级相对于乙醚压力和一氧化氮压力。最大限度地抑制反应被证明是最有可能的醚的分子分解。未抑制的反应主要是一个链式反应，其机理进行了讨论。根据实验证据，一氧化氮诱导的反应主要是由一氧化氮攻击乙醚时产生的自由基引发的。它也可能是一部分的分子分解醚碰撞所造成的一氧化氮。
Small quantities of nitric oxide reduce the rate of thermal decomposition of diethyl ether at 525 °C to about one-quarter. Much larger amounts accelerate the decomposition, but the concentration ranges in which the ‘maximally inhibited’ reaction and the ‘nitric-oxide-induced’ reactioncan be studied are so widely separated that these reactions can be treated as two distinct entities. The‘uninhibited’ reactionconstitutes a third. Reaction products and kinetics are recorded for all three, and nitric oxide consumption is measured for the first two. In all three the major products are the same, with secondary differences which are discussed. In the presence of nitric oxide small amounts of cyanides and other compounds are formed. In the nitric-oxide-induced reaction 1.4 molecules of ether are decomposed for each molecule of nitric oxide used up: in the maximally inhibited reaction the ratio, which is dependent on the ether pressure, is very much greater. The rate of the maximally inhibited reaction is independent of the concentration of nitric oxide, or of propylene, and the same for the two inhibitors (as is now proved by direct analysis). The first-order rate constant varies with the initial pressure of ether according to the equationkinhib.= (A[ether])/(1 +B[ether]) +C[ether]. The rate constant of the uninhibited reaction varies with ether pressure according to an expression which, although probably of different algebraical form, is empirically similar to the above over a considerable range. The nitric-oxide-induced reaction is nearly of the first order with respect both to ether pressure and to nitric oxide pressure. The maximally inhibited reaction is shown to be most probably a molecular decomposition of the ether. The uninhibited reaction is predominantly a chain reaction, the mechanism of which is discussed. The nitric-oxide-induced reaction, it is suggested on the basis of the experimental evidence, is largely initiated by a generation of radicals in an attack of nitric oxide on ether. It is possibly also in part a molecular decomposition of ether caused by collision with nitric oxide.