Determination of Henry' s Law constant for methyl hydroperoxide by long path FTIR*

摘要

Methyl hydroperoxide (MHP, CH_3OOH) is one of the main organic peroxides in the atmosphere. In order to understand how MHP partitions in atmospheric gas and liquid phases, the Henry's Law constant for its aqueous solution is determined. A novel technique is established for measuring gas-phase MHP concentration, i.e. the gas phase is collected by a gas-bag and then analyzed by long path Fourier transform infrared (LP-FTIR) spectrometry. At 283 K~303 K, the temperature dependence of the Henry's Law constant for MHP can be expressed as lnK_H=a/T-b, a=4386±140, b=9.19±0.48, where K_H is in unit of molar concentration per atm, and T is in degrees Kelvin. The standard heat of solution is 36.45±1.16 kJ centre dot K~(-1) centre dot mol~(-1).