Air Pollution Research Center, University of California, Riverside, California 92521, United States.
J Phys Chem A. 2011 Apr 7;115(13):2756-64. doi: 10.1021/jp112019s. Epub 2011 Mar 15.
Dichlorvos [2,2-dichlorovinyl dimethyl phosphate, (CH(3)O)(2)P(O)OCH═CCl(2)] is a relatively volatile in-use insecticide. Rate constants for its reaction with OH radicals have been measured over the temperature range 296-348 K and atmospheric pressure of air using a relative rate method. The rate expression obtained was 3.53 × 10(-13) e((1367±239)/T) cm(3) molecule(-1) s(-1), with a 298 K rate constant of (3.5 ± 0.7) × 10(-11) cm(3) molecule(-1) s(-1), where the error in the 298 K rate constant is the estimated overall uncertainty. In addition, rate constants for the reactions of NO(3) radicals and O(3) with dichlorvos, of (2.5 ± 0.5) × 10(-13) cm(3) molecule(-1) s(-1) and (1.7 ± 1.0) × 10(-19) cm(3) molecule(-1) s(-1), respectively, were measured at 296 ± 2 K. Products of the OH and NO(3) radical-initiated reactions were investigated using in situ atmospheric pressure ionization mass spectrometry (API-MS) and (OH radical reaction only) in situ Fourier transform infrared (FT-IR) spectroscopy. For the OH radical reaction, the major initial products were CO, phosgene [C(O)Cl(2)] and dimethyl phosphate [(CH(3)O)(2)P(O)OH], with equal (to within ±10%) formation yields of CO and C(O)Cl(2). The API-MS analyses were consistent with formation of (CH(3)O)(2)P(O)OH from both the OH and NO(3) radical-initiated reactions. In the atmosphere, the dominant chemical loss processes for dichlorvos will be daytime reaction with OH radicals and nighttime reaction with NO(3) radicals, with an estimated lifetime of a few hours.
敌敌畏[2,2-二氯乙烯基二甲基磷酸酯，（CH(3)O)(2)P(O)OCH═CCl(2)]是一种相对挥发性的使用中的杀虫剂。在 296-348 K 温度范围内和空气的大气压力下，使用相对速率法测量了其与 OH 自由基反应的速率常数。得到的速率表达式为 3.53×10(-13)e((1367±239)/T)cm(3)分子(-1)s(-1)，在 298 K 时的速率常数为(3.5±0.7)×10(-11)cm(3)分子(-1)s(-1)，其中 298 K 速率常数的误差是估计的总不确定度。此外，在 296±2 K 下，还测量了 NO(3)自由基和 O(3)与敌敌畏反应的速率常数，分别为(2.5±0.5)×10(-13)cm(3)分子(-1)s(-1)和(1.7±1.0)×10(-19)cm(3)分子(-1)s(-1)。使用原位大气压电离质谱（API-MS）和（仅 OH 自由基反应）原位傅里叶变换红外（FT-IR）光谱研究了 OH 和 NO(3)自由基引发反应的产物。对于 OH 自由基反应，主要的初始产物是 CO、光气[C(O)Cl(2)]和二甲磷酸[(CH(3)O)(2)P(O)OH]，CO 和 C(O)Cl(2)的生成率相等（±10%）。API-MS 分析与 OH 和 NO(3)自由基引发反应生成(CH(3)O)(2)P(O)OH 一致。在大气中，敌敌畏的主要化学损失过程将是白天与 OH 自由基反应和夜间与 NO(3)自由基反应，估计寿命为数小时。
