二氧化硫与次氯酸和次溴酸在冰表面发生的多相反应。

Heterogeneous reactions of SO2 with HOCl and HOBr on ice surfaces.

作者信息

Jin Ronghua, Chu Liang T

机构信息

Wadsworth Center, New York State Health Department and Department of Environmental Health Sciences, State University of New York at Albany, P.O. Box 509, Albany, New York 12201-0509, USA.

出版信息

J Phys Chem A. 2006 Jul 20;110(28):8719-28. doi: 10.1021/jp061796c.

DOI:10.1021/jp061796c

PMID:16836433

Abstract

The heterogeneous reactions of SO2 + HOX (X = Cl or Br) --> products on ice surfaces at low temperature have been investigated in a flow reactor coupled with a differentially pumped quadrupole mass spectrometer. Pseudo-first-order loss of SO2 over the ice surfaces has been measured under the conditions of concurrent HOX flow. The initial uptake coefficient of SO2 reaction with HOX has been determined as a function of HOX surface coverage, theta(HOX), on the ice. The initial uptake coefficients increase as the HOX coverage increases. The uptake coefficient can be expressed as gamma(t) = k(h)theta(HOX), where k(h) is an overall rate constant of SO2 + HOCl, which was determined to be (2.3 +/- 0.6) x 10(-19) and (1.7 +/- 0.5) x 10(-19) molecules(-1) x cm2 at 190 and 210 K, and k(h) of SO2 + HOBr is (6.1 +/- 2.0) x 10(-18) molecules(-1) x cm2 at 190 K. theta( HOX) is in the range 8.1 x 10(13)-9.1 x 10(14) molecules x cm(-2). The kinetic results of the heterogeneous reaction of SO2 + HOX on ice surface are interpreted using the Eley-Rideal mechanism. The activation energy of the heterogeneous reaction of SO2 with HOCl on ice surface was determined to be about -37 +/- 10 kJ/mol in the 190-238 K range.

摘要

在一个与差分抽气四极杆质谱仪联用的流动反应器中，研究了低温下冰表面上SO₂ + HOX（X = Cl或Br）→产物的非均相反应。在HOX气流同时存在的条件下，测量了SO₂在冰表面的准一级损失。已确定SO₂与HOX反应的初始摄取系数是冰上HOX表面覆盖度θ(HOX)的函数。初始摄取系数随HOX覆盖度的增加而增加。摄取系数可以表示为γ(t) = k(h)θ(HOX)，其中k(h)是SO₂ + HOCl的总速率常数，在190 K和210 K时分别确定为(2.3 ± 0.6)×10⁻¹⁹和( (1.7 ± 0.5)×10⁻¹⁹分子⁻¹×cm²，SO₂ + HOBr的k(h)在190 K时为(6.1 ± 2.0)×10⁻¹⁸分子⁻¹×cm²。θ(HOX)在8.1×10¹³ - 9.1×10¹⁴分子×cm⁻²范围内。使用埃利-里德机理对冰表面上SO₂ + HOX非均相反应的动力学结果进行了解释。在190 - 238 K范围内，冰表面上SO₂与HOCl非均相反应的活化能确定为约 - 37 ± 10 kJ/mol。