Room temperature and shock tube study of the reaction HCO+O2 using the photolysis of glyoxal as an efficient HCO source.
Room temperature and shock tube study of the reaction HCO+O2 using the photolysis of glyoxal as an efficient HCO source.
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使用乙二醛的光解作为有效的 HCO 源，在室温和激波管中研究 HCO O2 反应。
DOI：
10.1021/jp055168r
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
G. Friedrichs
中科院分区：
文献类型：
--
作者：
M. Colberg;G. Friedrichs
反应1的速率，HCO+O2-> HO 2 +CO，已经（i）在室温下使用慢流反应器装置（20 mbar<p<500 mbar）和（ii）在反射冲击波（0.82 bar<p<1.84 bar）之后在739 K<T<1108 K的温度范围内使用微扰方法确定。继193 nm的准分子激光光解乙二醛在Ar中的混合物，浓度-时间曲线使用频率调制（FM）检测HCO在波长λ =614.752 nm的测量。在向反应混合物中加入和不加入O2的情况下测量的HCO浓度-时间曲线之间观察到的差异几乎完全归因于反应1。测定的速率常数k1（295 K）=（3.55+/-0.05 x10（12）cm ~ 3 mol ~（-1）s ~（-1），k1（739-1108 K）=3.7x10（13）exp（-13 kJ mol ~（-1）/RT）cm ~ 3 mol ~（-1）s ~（-1）（Δ log k1=+/-0.16），表明反应1在高温下对温度有轻微的正依赖性。此外，乙二醛（CHO）2的193 nm光解已被证明是一种有效的HCO源。除了HCO，前体的光解也产生H原子。初始生成的H原子和HCO自由基的比率f=[H]0/[HCO] 0总，被发现依赖于总密度ρ。在室温下，其变化范围为f=1.6（rho= 8x 10（-7）mol cm-3）至f=3.0（rho= 2x 10（-5）mol cm-3）。H原子通过反应4（H+（CHO）2->H2+HCO+CO）转化为另外的HCO自由基。反应4的速率常数由无扰光解实验确定为k4（295 K）=（3.6+/-0.3 x10（10）cm ~ 3 mol ~（-1）s ~（-1）和k4（769-1107 K）= 5.4 × 10（13）exp（-18 kJ mol ~（-1）/RT）cm ~ 3 mol ~（-1）s ~（-1）（Δ log k4=+/-0.12）。
The rate of the reaction 1, HCO+O2-->HO2+CO, has been determined (i) at room temperature using a slow flow reactor setup (20 mbar<p<500 mbar) and (ii) in the temperature range 739 K<T<1108 K behind reflected shock waves (0.82 bar<p<1.84 bar) employing a perturbation approach. Following the 193 nm excimer laser photolysis of mixtures of glyoxal in Ar, concentration-time profiles were measured using frequency modulation (FM) detection of HCO at a wavelength of lambda=614.752 nm. Observed differences between HCO concentration-time profiles measured with and without O2 added to the reaction mixtures could be almost exclusively attributed to reaction 1. The determined rate constants, k1(295 K)=(3.55+/-0.05)x10(12) cm3 mol-1 s-1, k1(739-1108 K)=3.7x10(13) exp(-13 kJ mol-1/RT) cm3 mol-1 s-1 (Delta log k1=+/-0.16), reveal a slightly positive temperature dependence of reaction 1 at high temperatures. Furthermore, the 193 nm photolysis of glyoxal, (CHO)2, has been proven to be an efficient HCO source. Besides HCO, photolysis of the precursor also produces H atoms. The ratio of initially generated H atoms and HCO radicals, f=[H]0/[HCO]0total, was found to depend on the total density rho. At room temperature, it varies from f=1.6 at rho=8x10(-7) mol cm-3 to f=3.0 at rho=2x10(-5) mol cm-3. H atoms are transformed via reaction 4, H+(CHO)2-->H2+HCO+CO, into additional HCO radicals. The rate constants of reaction 4 were determined from unperturbed photolysis experiments to be k4(295 K)=(3.6+/-0.3)x10(10) cm3 mol-1 s-1 and k4(769-1107 K)=5.4x10(13)exp(-18 kJ mol-1/RT) cm3 mol-1 s-1(Delta log k4=+/-0.12).