Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL-60439, USA.
Phys Chem Chem Phys. 2011 Mar 7;13(9):3686-700. doi: 10.1039/c0cp01541e. Epub 2010 Dec 24.
The dissociation of 1, 2 and 4% 1,4-dioxane dilute in krypton was studied in a shock tube using laser schlieren densitometry, LS, for 1550-2100 K with 56 ± 4 and 123 ± 3 Torr. Products were identified by time-of-flight mass spectrometry, TOF-MS. 1,4-dioxane was found to initially dissociate via C-O bond fission followed by nearly equal contributions from pathways involving 2,6 H-atom transfers to either the O or C atom at the scission site. The 'linear' species thus formed (ethylene glycol vinyl ether and 2-ethoxyacetaldehyde) then dissociate by central fission at rates too fast to resolve. The radicals produced in this fission break down further to generate H, CH(3) and OH, driving a chain decomposition and subsequent exothermic recombination. High-level ab initio calculations were used to develop a potential energy surface for the dissociation. These results were incorporated into an 83 reaction mechanism used to simulate the LS profiles with excellent agreement. Simulations of the TOF-MS experiments were also performed with good agreement for consumption of 1,4-dioxane. Rate coefficients for the overall initial dissociation yielded k(123Torr) = (1.58 ± 0.50) × 10(59) × T(-13.63) × exp(-43970/T) s(-1) and k(58Torr) = (3.16 ± 1.10) × 10(79) × T(-19.13) × exp(-51326/T) s(-1) for 1600 < T < 2100 K.
在 1550-2100 K 的温度范围内，使用激光纹影密度测量法（LS）和 56 ± 4 及 123 ± 3 托的压力在激波管中研究了 1%、2%和 4%的 1,4-二恶烷在氪气中的离解。通过飞行时间质谱（TOF-MS）来鉴定产物。研究发现，1,4-二恶烷最初通过 C-O 键的断裂而离解，随后通过 2,6 H 原子转移到断裂部位的 O 或 C 原子，几乎相等地参与了反应途径。由此形成的“线性”物种（乙烯基乙二醇基醚和 2-乙氧基乙醛）然后通过中心断裂而离解，其速率太快而无法分辨。在这个裂变中产生的自由基进一步分解，生成 H、CH(3) 和 OH，从而引发链式分解和随后的放热重组。使用高级从头计算方法开发了用于离解的势能面。这些结果被纳入一个 83 个反应机制中，用于模拟 LS 轮廓，具有极好的一致性。还对 TOF-MS 实验进行了模拟，与 1,4-二恶烷的消耗情况非常吻合。总的初始离解的速率系数为 k(123Torr) = (1.58 ± 0.50) × 10(59) × T(-13.63) × exp(-43970/T) s(-1) 和 k(58Torr) = (3.16 ± 1.10) × 10(79) × T(-19.13) × exp(-51326/T) s(-1)，1600 < T < 2100 K。
