作者:J. Platz、J. Sehested、T. Mgelberg、O. J. Nielsen、T. J. Wallington
DOI:10.1039/a700598i
日期:——
A pulse radiolysis technique was used to measure the UV absorption spectra of c-C
4
H
7
O
2
and (c-C
4
H
7
O
2
)O
2
radicals over the range 220–320 nm, σ(c-C
4
H
7
O
2
)
250nm
= (5.9 ± 0.6) × 10
−18
and σ[(c-C
4
H
7
O
2
)O
2
]
240nm
= (4.8 ± 0.8) × 10
−18
cm
2
molecule
−1
. The observed self-reaction rate constants for the c-C
4
H
7
O
2
and (c-C
4
H
7
O
2
)O
2
radicals, defined as −d[c-C
4
H
7
O
2
]/dt = 2k
4
[c- C
4
H
7
O
2
]
2
and −d[(c-C
4
H
7
O
2
)O
2
]/dt = 2k
5obs
[(c-C
4
H
7
O
2
)O
2
]
2
were k
4
= (3.3 ± 0.4) × 10
−11
and k
5obs
= (7.3 ± 1.2) × 10
−1 2
cm
3
molecule
−1
s
−1
. The rate constants for reactions of (c-C
4
H
7
O
2
)O
2
radicals with NO and NO
2
were k
6
(1.2 ± 0.3) × 10
−11
and k
7
= (1.3 ± 0.3) × 10
−11
cm
3
molecule
−1
s
−1
, respectively. The rate constants for the reaction of F atoms with 1,4-dioxane and the reaction of c-C
4
H
7
O
2
radicals with O
2
, were k
3
= (2.4 ± 0.7) × 10
−10
and k
2
= (8.8 ± 0.9) × 10
−12
cm
3
molecule
−1
s
−1
, respectively. A relative rate technique was used to measure the rate constant for the reaction of Cl atoms with 1,4-dioxane, k
17
= (2.0 ± 0.3) × 10
−10
cm
3
molecule
−1
s
−1
. A long-pathlength FTIR spectrometer coupled to a smog chamber system was used to show that the sole atmospheric fate of the alkoxy radical (c-C
4
H
7
O
2
)O is decomposition via C–C bond scission leading to the formation of H(O)COCH
2
CH
2
OC(O)H (ethylene glycol diformate).
使用脉冲辐射分解技术测量了 220-320 纳米范围内 c-C 4 H 7 O 2 和 (c-C 4 H 7 O 2 )O 2 自由基的紫外吸收光谱,σ(c-C 4 H 7 O 2 ) 250nm = (5.9 ± 0.6) × 10 -18 和 σ[(c-C 4 H 7 O 2 )O 2 ] 240nm = (4.8 ± 0.8) × 10 -18 cm 2 molecule -1 。观察到的 c-C 4 H 7 O 2 和 (c-C 4 H 7 O 2 )O 2 自由基的自反应速率常数定义为-d[c-C 4 H 7 O 2 ]/dt = 2k 4 [c- C 4 H 7 O 2 ] 2 和-d[(c-C 4 H 7 O 2 )O 2 ]/dt = 2k 5obs [(c-C 4 H 7 O 2 )O 2 ] 2,即 k 4 = (3. 3 ± 0.4) × 10 cm 2 分子-1。3 ± 0.4) × 10 -11,k 5obs = (7.3 ± 1.2) × 10 -1 2 cm 3 molecule -1 s -1 。(c-C 4 H 7 O 2 )O 2 自由基与 NO 和 NO 2 反应的速率常数分别为 k 6 (1.2 ± 0.3) × 10 -11 和 k 7 = (1.3 ± 0.3) × 10 -11 cm 3 molecule -1 s -1 。F 原子与 1,4-二氧六环反应和 c-C 4 H 7 O 2 自由基与 O 2 反应的速率常数分别为 k 3 = (2.4 ± 0.7) × 10 -10 和 k 2 = (8.8 ± 0.9) × 10 -12 cm 3 molecule -1 s -1 。使用相对速率技术测量了 Cl 原子与 1,4-二氧六环反应的速率常数 k 17 = (2.0 ± 0.3) × 10 -10 cm 3 分子 -1 s -1 。与烟雾室系统耦合使用的长波长傅立叶变换红外光谱仪表明,烷氧基自由基 (c-C 4 H 7 O 2 )O 在大气中的唯一归宿是通过 C-C 键断裂分解,形成 H(O)COCH 2 CH 2 OC(O)H(乙二醇二甲酸酯)。