Air Pollution Research Center, University of California, Riverside, California 92521, USA.
J Phys Chem A. 2010 Mar 18;114(10):3523-32. doi: 10.1021/jp911668h.
Rate constants for the reactions of OH radicals with isopropyl methyl methylphosphonate [(CH(3))(2)CHOP(O)(CH(3))OCH(3); IMMP] and dimethyl N,N-dimethylphosphoroamidate [(CH(3)O)(2)P(O)N(CH(3))(2); DMDMPA] have been measured over the temperature range 283-350 K and atmospheric pressure of air using a relative rate method. The rate expressions obtained were 2.72 x 10(-13) e((1642+/-144)/T) cm(3) molecule(-1) s(-1) (6.72 x 10(-11) cm(3) molecule(-1) s(-1) at 298 K) for OH + IMMP and 6.05 x 10(-13) e((1185+/-144)/T) cm(3) molecule(-1) s(-1) (3.23 x 10(-11) cm(3) molecule(-1) s(-1) at 298 K) for OH + DMDMPA. In addition, rate constants for the reactions of NO(3) radicals and O(3) with IMMP were measured at 296 +/- 2 K, of (4.8 +/- 2.1) x 10(-16) and <7 x 10(-20) cm(3) molecule(-1) s(-1), respectively. Products of the OH radical-initiated reactions were investigated using gas chromatography, in situ atmospheric pressure ionization mass spectrometry (API-MS), and in situ Fourier transform infrared (FT-IR) spectroscopy. For the OH + IMMP reaction, the major initial products appear to be CH(3)OP(O)(CH(3))OC(O)CH(3) + (*)CH(3), with subsequent reactions of the methyl radical in the presence of NO(x) leading to HCHO, CH(3)ONO, and CH(3)ONO(2). For the OH + DMDMPA reaction, (CH(3)O)(2)P(O)N(CH(3))CHO was observed as a significant product. Possible reaction mechanisms are discussed.
羟基自由基与异丙基甲基甲基膦酸酯[(CH(3))(2)CHOP(O)(CH(3))OCH(3); IMMP]和二甲氨基 N,N-二甲基磷酰胺[(CH(3)O)(2)P(O)N(CH(3))(2); DMDMPA]的反应速率常数在 283-350 K 和大气压的空气中使用相对速率法进行了测量。得到的速率表达式为 2.72 x 10(-13) e((1642+/-144)/T) cm(3) molecule(-1) s(-1) (6.72 x 10(-11) cm(3) molecule(-1) s(-1)在 298 K 时)对于 OH + IMMP 和 6.05 x 10(-13) e((1185+/-144)/T) cm(3) molecule(-1) s(-1) (3.23 x 10(-11) cm(3) molecule(-1) s(-1)在 298 K 时)对于 OH + DMDMPA。此外，还测量了 296 +/- 2 K 时 NO(3)自由基和 O(3)与 IMMP 的反应速率常数，分别为 (4.8 +/- 2.1) x 10(-16) 和 <7 x 10(-20) cm(3) molecule(-1) s(-1)。使用气相色谱、原位大气压电离质谱 (API-MS) 和原位傅里叶变换红外 (FT-IR) 光谱法研究了 OH 自由基引发反应的产物。对于 OH + IMMP 反应，主要的初始产物似乎是 CH(3)OP(O)(CH(3))OC(O)CH(3) + (*)CH(3)，随后在 NO(x)存在下甲基自由基的反应导致 HCHO、CH(3)ONO 和 CH(3)ONO(2)。对于 OH + DMDMPA 反应，观察到 (CH(3)O)(2)P(O)N(CH(3))CHO 是一个重要的产物。讨论了可能的反应机制。
