一种可能形成POPs途径的初探-气相苯的氯化反应

A Preliminary Approach to Mimic the Formation of POPs in the Atmosphere:Chlorination of Benzene in the Gas Phase

用串联质谱碰撞室模拟大气环境研究了持久性有机污染物(POPs)形成过程,实验发现,经离子-分子反应可以生成氯苯类化合物。以中性苯与酰氯为反应物在离子源进行反应,在苯含量为4×10-3Pa、酰氯含量为4×10-4Pa时,氯苯的生成量为5×10-8Pa,远远高于背底浓度5×10-9Pa。对氯苯类化合物的形成,大气环境明显优于质谱环境,实验结果表明,在大气中经离子-分子反应形成POPs是可能的。

The process of persistent organic pollutants（ POPs） formation was studied by using the collision chamber of tandem mass spectrometer instead of atmospheric environment. It is found that chlorobenzenes can be formed through gas phase ion-molecule reaction in the collision chamber. And the formation of chlorobenzenes in the ion source of the mass spectrometer is also observed. When benzene content is 4 × 10 ^-3 Pa and acetyl chloride content is 4 × 10 ^-4 Pa,the chlorobenzene content reaches 5 × 10 ^-8 Pa,while the background of chlorobenzene is only 5 × 10 ^-9 Pa. So it is possible that the formation of chlorobenzene by gas phase ion-molecule reactions,because chlorobenzene is formed easier in atmosphere than that in the collision chamber.