Recent field and experimental studies have suggested that acid-base reactions of alkylamines may play an important role in secondary aerosol formation. We investigated the heterogeneous chemistry of ethylamine (EA), diethylamine (DEA) and triethylamine (TEA) on liquid H2SO4 (1 wt%–80 wt%). Irreversible reactive uptakes were observed for all three alkylamines. The reactive uptake coefficients (γ ) of alkylamines increased with the acid concentration, and the γ value for DEA appeared to increase slightly faster than that of EA and TEA. The potential roles in secondary aerosol formation of different alkylamines are briefly discussed.
Unsaturated alcohols are important components in complex mixtures of oxygenated volatile organic compounds,and play a significant role in atmospheric chemistry.The uptake kinetics of 3-buten-1-ol (BO31),4-penten-1-ol (PO41) and 3-methyl3-buten-1-ol (MBO331) into 20 wt%-80 wt% H2SO4 solutions were studied,using a rotated wetted-wall reactor coupled to a differentially pumped single-photon ionization time of flight mass spectrometer (SPI-TOFMS).With increasing acidity,the uptake processes changed from reversible to irreversible (reactive).Reactive uptake was observed in 60 wt%-80 wt%,50 wt%-80 wt% and 30 wt%-80 wt% H2SO4 solutions for BO31,PO41 and MBO331,respectively.Reactive uptake coefficients were acquired and are reported here for the first time.Reactivity order followed the trend:BO31
Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.
The electronic structures of six mono-terpenoids and two of their oxygenated derivatives were studied by He I photoelectron spectroscopy(PES).The observed bands were interpreted on the basis of empirical arguments and theoretical calculations.The first vertical ionization potentials for β-pinene,α-terpinene,terpinolene,γ-terpinene,limonene,myrcene,citral,and terpinene-4-ol were determined to be 8.73,7.57,8.26,8.30,8.53,8.68,8.71,and 8.77 eV,respectively.Most of these values have not been determined by PES before.The correlations of the first vertical ionization potentials of these compounds to the natural logarithms of rate constants for their reactions with the radicals OH,NO3,and O3 were determined.The correlation coefficients for their reactions with OH,NO3,and O3 were 0.97,0.91,and 0.95,respectively.This method is a powerful technique for predicting the rate constants for the atmospheric oxidation reactions of terpenoids.
WANG XiaoPeng TONG ShengRui GE MaoFa WANG WeiGang WANG DianXun
Using an improved smog chamber system,the temperature dependence of OH radical reaction with EMS was investigated over the temperature range of 297-346 K at 1.01×105 Pa pressure of air. The Arrhenius expression of the reaction was obtained for the first time. The mechanism of the reaction was also investigated.
Unsaturated alcohols are important components in complex mixtures of oxygenated volatile organic compounds,and...
XU ZhiFang~(1,2),LIU Ze~2,GE MaoFa~(2*) & WANG WeiGang~2 1 Key Laboratory of Engineering Geomechanics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China
