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• 基金项目：

• 林子瑜
• 中国环境科学研究院

• 王文兴
• 中国环境科学研究院

• 摘要：本文通过烯烃-臭氧气相反应产生的Criegee中间物,研究其与二氧化硫及乙醛的反应动力学及反应性。实验结果表明:（1）稳定的Criegee中间物是通过烯烃-臭氧起始反应生成“热”的中间物和第三种惰性分子碰撞形成的,随后与二氧化硫或乙醛发生双分子反应;（2）在我们的实验条件下,当加入足够过量的乙醛时,可以用反应生成的次级臭氧化物产率的极限值来表征稳定的Criegee中间物的生成量;（3）通过测定稳定的Criegee中间物的单分子分解速度常数和它的双分子反应速度常数的比值,得到了稳定的CH₂OO、CH₃CHOO与二氧化硫、乙醛反应的速度常数的比值。

• Abstract：Kinetics and reactivity of the reaction of the Criegee intermediate (CH₂OO type biradical) with SO₂ and CH₃CHO were studied by the gas-phase olefin-ozone reactions. Experiments were carried out at atmospheric pressure in the evacuable and bakable smog chamber whose volume is 6m³. The results were shown as follows: The scheme of the reaction sequences was proposed. Stern-Volmer type equations were obtained for C₂H₄-O₃-SO₂/or CH₃CHO reactions and trans-2-butene-O₃-SO₂/or CH₃CHO reactions, and they give the branching ratio, a, which corresponds to the fraction of the intermediate which can be stabilized and can undergo bimolecular reactions. From the intercept the value of a is 0.46 for the ethylene-ozone-acetaldehyde reaction, a is 0.24 for the trans-2-butene-acetaldehyde-ozone reaction.From the slopes of equations the rate constant ratio of decomposition of the stabilized Criegee intermediate to its bimolecular reaction was obtained to be 1.04# 10¹³ molecule cm^-3 and 3.32×10¹³ molecule cm^-3 for the ethylene-ozone-sulfur dioxide-dry air reaction and the ethylene-ozone-acetaldehyde-dry air reaction, respectively. Therefore the reaction rate constant of stabilized peroxymethylene intermediate with SO₂ is three times as large as that with CH₃CHO. For the trans-2-butene-ozone-acetaldehyde reaction, kdec/kCH₃CO=6.11×10¹³ molecule cm^-3. For the trans-2-butene-ozone-sulfurdioxide reaction,kdec/kSO₂=3.35×10¹³ molecule cm^-3.The reaction rate constant of stabilized CH₃CHOO intermediate with SO₂ is two times as large as that with CH₃CHO.

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