臭氧过量条件下异戊二烯氧化生成羰基化合物的产率

YIELDS OF CARBONYL PRODUCTS FROM THE GAS-PHASE OXIDATION OF ISOPRENE WITH EXCESS OZONE

利用长光路傅立叶变换红外光谱(LP-FTIR)原位跟踪的方法,模拟研究了异戊二烯与过量臭氧氧化反应产生羰基化合物的过程.在反应温度(294±2)K,压力为1·01×105Pa空气,O3过量的条件下,异戊二烯很快反应完全,反应中生成的羰基产物主要包括甲基丙烯醛(MACR)、甲基乙烯基酮(MVK)、丙酮醛(MG)和甲醛(HCHO);产物中还包括甲酸(HCOOH)、一氧化碳和二氧化碳.由于MACR和MVK继续与O3反应直至完全,它们的产率随时间而变化,反应过程中观测到的最大产率分别为0·33±0·02和0·21±0·02;而MG,HCHO,HCOOH,CO和CO2不与O3发生反应,最终产率分别为0·48±0·03,0·87±0·03,0·49±0·03,0·60±0·03和0·65±0·10.异戊二烯臭氧氧化反应对大气羰基化合物特别是甲醛和丙酮醛具有重要贡献.

The experimental simulation of carbonyl products formation in the atmospheric gas-phase reaction of isoprene with excess ozone in the presence of water vapor was carried out at 294 ±2K temperature and 1.01 × 10^5 Pa total air pressure, using the long path Fourier transformation infrared （ Long Path FTIR） spectrometry. The results indicated isoprene was soon consumed under the condition of excess ozone. During the reaction, the the experimental conditions, so their yields relative to isoprene conversion were variable along the reaction time, with the maximum yields observed as 0. 33 ± 0. 02 for MACR and 0. 21 ± 0. 02 for MVK respectively. MG, HCHO, HCOOH, CO and CO2are inactive to ozone, and their final yields relative to isoprene conversion were 0. 48 ± 0. 03,0. 87 ± 0. 03, 0. 49 ± 0. 03,0. 60 ± 0. 03 and 0. 65 ± 0. 10, respectively. The ozonolysis of isoprene has a significant contribution to atmospheric carbonyls, especially to formaldehyde and methylglyoxal.