Shock-tube experiments have been performed to investigate the thermal decomposition of the oxygenated hydrocarbon dimethoxymethane (DMM; CH₃OCH₂OCH₃). The primary initial reaction channels of DMM decomposition are considered to be the two bond fissions: CH₃OCH₂OCH₃ → CH₃O + CH₂OCH₃ (1) and CH₃OCH₂OCH₃ → CH₃ + OCH₂OCH₃ (2). In the present work, two shock-tube facilities and three different detection techniques have been combined: Behind reflected shock waves, we have carried out time-resolved measurements of (i) the formation of H atoms using the highly sensitive H-ARAS (Atomic Resonance Absorption Spectrometry) technique and (ii) the depletion of the DMM reactant by high-repetition-rate time-of-flight mass spectrometry (HRR-TOF-MS). In addition, (iii) the temperature-dependent composition of stable reaction products was measured in single-pulse shock-tube experiments via gas chromatography (GC/MS). The experiments span a temperature range of 1100–1430 K, a pressure range of 1.2–2.5 bar, and initial reactant mole fractions from 0.5 ppm (for H-ARAS experiments) up to 10 000 ppm (for HRR-TOF-MS experiments). Experimental rate constants k_total, k_total = k₁ + k₂, obtained from these three completely different methods were in excellent agreement among each other, i.e., deviations are within ±30–40%, and they can be well represented by the Arrhenius expression k_total(T) = 10^13.28±0.27 exp(−247.90 ± 6.36 kJ mol^–1/RT) s^–1 (valid over the 1100–1400 K temperature and the 1.2–2.5 bar pressure range). By replacing the respective k_total values used in a recently published DMM chemical kinetics combustion mechanism (Vermeire et al. Combust. Flame2018, 190, 270–283), it was also possible to successfully reproduce measured product distributions.

中文翻译：

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直接测量二甲氧基甲烷热分解的高温速率常数，激波管和建模研究

已经进行了激波管实验，以研究含氧烃二甲氧基甲烷（DMM; CH ₃ OCH ₂ OCH ₃）的热分解。DMM分解​​的主要初始反应通道被认为是两个键裂变：CH ₃ OCH ₂ OCH ₃ →CH ₃ O + CH ₂ OCH ₃（1）和CH ₃ OCH ₂ OCH ₃ →CH ₃ + OCH ₂ OCH ₃（2）。在目前的工作中，将两个激波管设施和三种不同的检测技术结合在一起：在反射的激波后面，我们已经进行了时间分辨测量（i）使用高度敏感的H-ARAS（原子）形成H原子。共振吸收光谱法）（ii）通过高重复速率飞行时间质谱（HRR-TOF-MS）去除DMM反应物。另外，（iii）通过气相色谱法（GC / MS）在单脉冲冲击管实验中测量了稳定反应产物的温度依赖性组成。实验的温度范围为1100-1430 K，压力范围为1.2-2.5 bar，初始反应物摩尔分数从0.5 ppm（对于H-ARAS实验）到10000 ppm（对于HRR-TOF-MS实验） 。实验速率常数k通过这三种完全不同的方法获得的_total，k _total = k ₁ + k ₂，彼此之间具有极好的一致性，即偏差在±30–40％之内，并且可以用Arrhenius表达式k _total很好地表示（T）= 10 ^13.28±0.27 exp（−247.90±6.36 kJ mol ^–1 / RT）s ^–1（在1100–1400 K温度和1.2–2.5 bar压力范围内有效）。通过替换最近发表的DMM化学动力学燃烧机理中使用的各个k_总值（Vermeire等人，燃烧 火焰2018，190，270-283），也有人可能成功地再现测定产物分布。