在这项研究中,使用定制设计的小型密闭压力容器测试(MCPVT)研究了异戊二烯的氧化特性。结果表明,异戊二烯不稳定,在氮气气氛下发生聚合。在氧气气氛下,异戊二烯的氧化过程分为三个阶段:(1)异戊二烯与氧气反应生成过氧化物;(2)过氧化物通过热分解产生自由基;(3)自由基引起复杂的氧化和热失控反应。异戊二烯的氧化符合二级反应动力学,活化能为86.88kJ·mol-1。通过差示扫描量热法(DSC)确定总氧化产物和纯化的过氧化物混合物的热分解特性。初始放热温度Ton为371.17K和365.84K,分别。QDSC的分解热分别为816.66J·g-1和991.08J·g-1。这表明高浓度的异戊二烯过氧化物具有高的热失控风险。热失控实验结果表明,异戊二烯氧化的温度和压力容易迅速升高,这表明氧化反应是危险的。通过气相色谱-质谱(GC-MS)分析异戊二烯的反应产物。主要氧化产物为甲基乙烯基酮,甲基丙烯醛,3-甲基呋喃,等。主要的热失控产物是二甲氧基甲烷,2,3-戊二酮,萘,等。根据反应产物,提出了异戊二烯可能的反应途径。
In this study, the oxidation characteristics of
isoprene were investigated using a custom-designed mini closed pressure vessel test (MCPVT). The results show that
isoprene is unstable and polymerization occurs under a nitrogen atmosphere. Under an oxygen atmosphere, the oxidation process of
isoprene was divided into three stages: (1)
isoprene reacts with oxygen to produce peroxide; (2) Peroxides produce free radicals through thermal decomposition; (3) Free radicals cause complex oxidation and thermal runaway reactions. The oxidation of isoprene conforms to the second-order reaction kinetics, and the activation energy was 86.88 kJ·mol-1. The thermal decomposition characteristics of the total oxidation product and purified peroxide mixture were determined by differential scanning calorimetry (DSC). The initial exothermic temperatures Ton were 371.17 K and 365.84 K, respectively. And the decomposition heat QDSC were 816.66 J·g-1 and 991.08 J·g-1, respectively. It indicates that high concentration of
isoprene peroxide has a high risk of thermal runaway. The results of thermal runaway experiment showed that the temperature and pressure of isoprene oxidation were prone to rise rapidly, which indicates that the oxidation reaction was dangerous. The reaction products of isoprene were analyzed by gas chromatography-mass spectrometry (GC-MS). The main oxidation products were methyl vinyl ketone, methacrolein, 3-methylfuran, etc. The main thermal runaway products were dimethoxymethane, 2,3-pentanedione, naphthalene, etc. Based on the reaction products, the possible reaction pathway of
isoprene was proposed.