Decomposition of 2-methylfuran. Experimental and modeling study
Decomposition of 2-methylfuran. Experimental and modeling study
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DOI：
10.1021/jp962646c
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发表时间：
1997-02-06
影响因子：
2.9
通讯作者：
Shashua, R
中科院分区：
文献类型：
--
作者：
Lifshitz, A;Tamburu, C;Shashua, R
在1100-1400 K的温度范围内，在总密度为3 × 10 ~（-5）mol/cm ~ 3的压力驱动单脉冲激波管中，研究了2-甲基呋喃在反射激波后的热反应。在冲击加热条件下，得到了大量由环的单分子断裂和连续的自由基反应产生的产物。单分子分解是由两个平行的通道引发的：（1）1，2-氢原子从C（5）迁移到C（4）和（2）甲基从C（2）迁移到C（3）。每个通道之后是两个平行的环裂解模式。在第一个通道中，环中O-C（2）和C（4）-C（5）键的断裂产生CO和C4 H6的不同异构体，而O-C（2）和C（3）-C（4）键的断裂产生CH 2CO和两种异构体C3 H4。在第二个通道中，环中的O-C（5）和C（2）-C（3）键断裂，再次产生CO和C4 H6的异构体，而在第二个模式中，O-C（5）、C（2）-C（3）和C（3）-C（4）被断裂，产生CO、C2 H2和C2 H4。四种C4 H6异构体按丰度递减顺序为1，3-丁二烯、1-丁炔、1，2-丁二烯和2-丁炔。主要的分解产物是一氧化碳，其总生成速率常数估计为k（CO）= 10（15.88）exp（-78.3 × 10（3）/RT）s（-1），其中R以cal/（K mol）为单位表示。在冲击后样品中发现的其他产物按丰度降序排列为C4 H4、C2 H3、CH 4、p-C3 H4、C2 H6、C2 H4、a-C3 H4、C6 H6、C4 H4 O、C3 H6和C4 H2。根据一级速率常数，2-甲基呋喃的总分解由k（总）= 10（14.78）exp（-71.8 X 10（3）/RT）s（-1）给出。该速率和一氧化碳的产生速率略高于呋喃分解中发现的速率。得到了分解产物之间的氧-碳质量平衡。一个由36个物种和约100个基元反应组成的反应方案占本研究所涵盖的温度范围内的产物分布。给出了各种反应产物形成的一阶Arrhenius速率参数，提出了一种反应方案，并给出了计算机模拟和灵敏度分析的结果。讨论了呋喃和2-甲基呋喃反应的异同。
The thermal reactions of 2-methylfuran were studied behind reflected shock waves in a pressurized driver single pulse shock tube over the temperature range 1100-1400 K and with overall densities of similar to 3 x 10(-5) mol/cm(3). A large number of products resulting from unimolecular cleavage of the ring and consecutive free radical reactions were obtained under shock heating. The unimolecular decomposition is initiated by two parallel channels: (1) 1,2-hydrogen atom migration from C(5) to C(4) and (2) a methyl group migration from C(2) to C(3) in the ring. Each channel is followed by two parallel modes of ring cleavage. In the first channel, breaking the O-C(2) and the C(4)-C(5) bonds in the ring yields CO and different isomers of C4H6, whereas breaking of the O-C(2) and the C(3)-C(4) bonds yields CH2CO and two isomers C3H4. In the second channel, breaking the O-C(5), and C(2)-C(3) bonds in the ring yields again CO and isomers of C4H6, whereas in the second mode O-C(5), C(2)-C(3), and C(3)-C(4) are broken to yield CO, C2H2, and C2H4. The four C4H6 isomers in decreasing order of abundance were 1,3-butadiene, 1-butyne, 1,2-butadiene, and 2-butyne. The major decomposition product is carbon monoxide, The rate constant for its overall formation is estimated to be k(CO) = 10(15.88) exp(-78.3 x 10(3)/RT) s(-1), where R is expressed in units of cal/(K mol). Other products that were found in the postshock samples in decreasing order of abundance were C4H4, C2H3, CH4, p-C3H4, C2H6, C2H4, a-C3H4, C6H6, C4H4O, C3H6, and C4H2. The total decomposition of 2-methylfuran in terms of a first order rate constant is given by k(total) = 10(14.78) exp(-71.8 x 10(3)/RT) s(-1). This rate and the production rate of carbon monoxide ate slightly higher than the ones found in the decomposition of furan. An oxygen-carbon mass balance among the decomposition products was obtained. A reaction scheme composed of 36 species and some 100 elementary reactions accounts for the product distribution over the temperature range covered in this study. First order Arrhenius rate parameters for the formation of the various reaction products are given, a reaction scheme is suggested, and results of computer simulation and sensitivity analysis are shown. Differences and similarities in the reactions of furan and 2-methylfuran are discussed.