Uptake kinetics of three epoxides into sulfuric acid solution
Uptake kinetics of three epoxides into sulfuric acid solution
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DOI：
10.1016/j.atmosenv.2012.04.001
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发表时间：
2012-09
影响因子：
5
通讯作者：
Tianhe Wang;Ze Liu;Weigang Wang;Maofa Ge
中科院分区：
文献类型：
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作者：
Tianhe Wang;Ze Liu;Weigang Wang;Maofa Ge
本文研究了异戊二烯环氧化物、丁二烯环氧化物（BMO）和丁二烯二环氧化物（BDO）在硫酸溶液中的吸收，这有助于了解大气中存在的环氧化物对酸性气溶胶的反应性。使用旋转湿壁反应器（RWW）与单光子电离飞行时间质谱仪（SPI-TOFMS）耦合测量这三种化合物在0 - 30 wt % H2SO 4溶液中的吸收。环氧化物被发现是非常容易采取的H2SO 4解决方案，即使在稀浓度的pH值水平。发现环氧化异戊二烯在pH = 4时可逆地分配到溶液中，而当pH ≤ 3时观察到不可逆吸收。在pH = 3 - 20wt%H2SO4溶液中，反应吸收系数为1.87 × 10 - 5 ~ 2.67 × 10 - 3。异戊二烯环氧化物的化学反应是反应性吸收的原因。通过质谱、气相色谱和傅立叶变换红外光谱等手段，确定气体产物为2-甲基-3-丁烯醛。丁二烯环氧化物的吸收行为与异戊二烯环氧化物相似，而丁二烯二环氧化物在0-30 wt %的整个酸度范围内不可逆地分配，并且从纯水到pH = 1的反应性吸收系数略有增加（0.849 × 10−4-1.36 × 10−4）。根据三种环氧化物分子结构的差异，分析比较了它们的反应活性与水解速率的关系。根据相应的反应吸收系数，计算了大气寿命，并讨论了大气含义。
This work presents a study of the uptake of isoprene epoxide, butadiene epoxide (BMO) and butadiene diepoxide (BDO) into sulfuric acid solutions which helps to understand the reactivity of epoxides existing in the atmosphere toward acidic aerosols. The uptake of these three compounds into 0−30 wt % H2SO4solutions were measured using a rotated wetted-wall reactor (RWW) coupled to a single-photon ionization time of flight mass spectrometer (SPI-TOFMS). The epoxides were found to be very easily taken up by H2SO4solutions even in dilute concentrations of pH levels. Isoprene epoxide was found to partition reversibly into solution at pH = 4, whereas irreversible uptake was observed when pH ≤ 3. We reported the reactive uptake coefficients from 1.87 × 10−5to 2.67 × 10−3for pH = 3−20 wt % H2SO4solutions. A chemical reaction for isoprene epoxide was responsible for the reactive uptake. By means of mass spectrometry, gas chromatography and FTIR spectroscopy, a gas product was identified to be 2-methyl-3-butenal. The uptake behavior of butadiene epoxide was similar with that of isoprene epoxide, while butadiene diepoxide partitioned irreversibly over the whole acidity range of 0–30 wt %, and the reactive uptake coefficients increased slightly (0.849 × 10−4–1.36 × 10−4) from pure water to pH = 1. The reactivity that displayed close dependence on the hydrolysis rates of the three epoxides was analyzed and compared according to their molecular structural differences. The atmospheric lifetimes were calculated and atmospheric implication was discussed based on the corresponding reactive uptake coefficients.