过冷硫酸表面丁醇膜层中的水分蒸发

Evaporation of water through butanol films at the surface of supercooled sulfuric acid.

作者信息

Lawrence Jennifer R, Glass Samuel V, Nathanson Gilbert M

机构信息

Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.

出版信息

J Phys Chem A. 2005 Aug 25;109(33):7449-57. doi: 10.1021/jp050042f.

DOI:10.1021/jp050042f

PMID:16834114

Abstract

The evaporation of water was monitored from 60, 64, and 68 wt % D(2)SO(4) at 213 K containing 0-0.18 M 1-butanol. Measurements were performed in vacuum using a mass spectrometer to record the velocities and relative fluxes of the desorbing D(2)O. In addition, the surface activity of butanol in the acid was characterized by hyperthermal argon atom scattering in conjunction with surface tension and butanol evaporation measurements. The segregated butyl species reach surface concentrations of approximately 4 x 10(14) cm(-2) (approximately 80% surface coverage) at 0.18 M bulk concentration. We find that the butyl films do not impede the evaporation of D(2)O from the acid to within the 5% uncertainty of the measurements. This result implies that small, soluble surfactants such as butanol form porous films that will not alter the growth or shrinkage of supercooled sulfuric acid droplets in the atmosphere.

摘要

在213K下，对含有0 - 0.18M正丁醇的60wt%、64wt%和68wt%D₂SO₄中的水蒸发进行了监测。测量是在真空中使用质谱仪进行的，以记录解吸的D₂O的速度和相对通量。此外，通过超热氩原子散射结合表面张力和丁醇蒸发测量，对酸中丁醇的表面活性进行了表征。在本体浓度为0.18M时，分离出的丁基物种表面浓度达到约4×10¹⁴ cm⁻²（约80%的表面覆盖率）。我们发现，在测量的5%不确定度范围内，丁基膜不会阻碍D₂O从酸中蒸发。这一结果表明，诸如丁醇之类的小的可溶性表面活性剂形成的多孔膜不会改变大气中过冷硫酸液滴的生长或收缩。