Moreno A, Gallego-Iniesta M P, Taccone R, Martín M P, Cabañas B, Salgado M S
Instituto de Investigación en Combustión y Contaminación Atmosférica. ICCA., CYTEMA, Universidad de Castilla La Mancha, Camino Moledores, s/n., 13071, Ciudad Real, Spain.
Environ Sci Pollut Res Int. 2014 Oct;21(19):11541-51. doi: 10.1007/s11356-014-3112-4. Epub 2014 Jun 10.
Acrylate esters are α,β-unsaturated esters that contain vinyl groups directly attached to the carbonyl carbon. These compounds are widely used in the production of plastics and resins. Atmospheric degradation processes of these compounds are currently not well understood. The kinetics of the gas phase reactions of OH radicals with methyl 3-methylacrylate and methyl 3,3-dimethylacrylate were determined using the relative rate technique in a 50 L Pyrex photoreactor using in situ FTIR spectroscopy at room temperature (298 ± 2 K) and atmospheric pressure (708 ± 8 Torr) with air as the bath gas. Rate coefficients obtained were (in units cm(3) molecule(-1) s(-1)): (3.27 ± 0.33) × 10(-11) and (4.43 ± 0.42) × 10(-11), for CH3CH═CHC(O)OCH3 and (CH3)2CH═CHC(O)OCH3, respectively. The same technique was used to study the gas phase reactions of hexyl acrylate and ethyl hexyl acrylate with OH radicals and Cl atoms. In the experiments with Cl, N2 and air were used as the bath gases. The following rate coefficients were obtained (in cm(3) molecule(-1) s(-1)): k3 (CH2═CHC(O)O(CH2)5CH3 + Cl) = (3.31 ± 0.31) × 10(-10), k4(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + Cl) = (3.46 ± 0.31) × 10(-10), k5(CH2═CHC(O)O(CH2)5CH3 + OH) = (2.28 ± 0.23) × 10(-11), and k6(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + OH) = (2.74 ± 0.26) × 10(-11). The reactivity increased with the number of methyl substituents on the double bond and with the chain length of the alkyl group in -C(O)OR. Estimations of the atmospheric lifetimes clearly indicate that the dominant atmospheric loss process for these compounds is their daytime reaction with the hydroxyl radical. In coastal areas and in some polluted environments, Cl atom-initiated degradation of these compounds can be significant, if not dominant. Maximum Incremental Reactivity (MIR) index and global warming potential (GWP) were also calculated, and it was concluded that these compounds have significant MIR values, but they do not influence global warming.
丙烯酸酯是α,β-不饱和酯，其乙烯基直接连接在羰基碳上。这些化合物广泛用于塑料和树脂的生产。目前对这些化合物在大气中的降解过程了解甚少。在室温（298±2K）和大气压（708±8托）下，以空气为浴气，在50L派热克斯玻璃光反应器中使用相对速率技术，通过原位傅里叶变换红外光谱法测定了OH自由基与3-甲基丙烯酸甲酯和3,3-二甲基丙烯酸甲酯的气相反应动力学。得到的速率系数（单位：cm³分子⁻¹秒⁻¹）分别为：CH₃CH═CHC(O)OCH₃为(3.27±0.33)×10⁻¹¹，(CH₃)₂CH═CHC(O)OCH₃为(4.43±0.42)×10⁻¹¹。采用相同技术研究了丙烯酸己酯和丙烯酸乙基己酯与OH自由基和Cl原子的气相反应。在Cl原子的实验中，使用N₂和空气作为浴气。得到以下速率系数（单位：cm³分子⁻¹秒⁻¹）：k₃(CH₂═CHC(O)O(CH₂)₅CH₃ + Cl) = (3.31±0.31)×10⁻¹⁰，k₄(CH₂═CHC(O)OCH₂CH(CH₂CH₃)(CH₂)₃CH₃ + Cl) = (3.46±0.31)×10⁻¹⁰，k₅(CH₂═CHC(O)O(CH₂)₅CH₃ + OH) = (2.28±0.23)×10⁻¹¹，k₆(CH₂═CHC(O)OCH₂CH(CH₂CH₃)(CH₂)₃CH₃ + OH) = (2.74±0.26)×10⁻¹¹。反应活性随双键上甲基取代基的数量以及-C(O)OR中烷基链长度的增加而增加。大气寿命的估计清楚地表明，这些化合物在大气中的主要损失过程是它们在白天与羟基自由基的反应。在沿海地区和一些污染环境中，Cl原子引发的这些化合物的降解即使不是主要的，也可能很显著。还计算了最大增量反应性（MIR）指数和全球变暖潜能值（GWP），得出的结论是这些化合物具有显著的MIR值，但它们不会影响全球变暖。
