Basicities of the 2-, 4-, 2,4-di-, and 2,6-disubstituted tert-butylpyridines in the gas phase and aqueous phase: steric effects in the solvation of tert-butyl-substituted pyridines and pyridinium cations

1984 ◽  
Vol 106 (16) ◽  
pp. 4341-4348 ◽  
Author(s):  
Harry P. Hopkins ◽  
D. V. Jahagirdar ◽  
P. S. Moulik ◽  
Donald H. Aue ◽  
Hugh M. Webb ◽  
...  
Keyword(s):  
Gas Phase ◽  
Aqueous Phase ◽  
Steric Effects ◽  
Tert Butyl ◽  
Substituted Pyridines ◽  
Pyridinium Cations

Inductive and steric effects on the gas-phase structure of tert-butyl formate. Electron diffraction and theoretical investigations

1998 ◽  
Vol 471 (1-3) ◽  
pp. 275-281 ◽  
Author(s):  
Hiroshi Takeuchi ◽  
Tomohiro Matsuoka ◽  
Takemasa Tsuji ◽  
Hiroyuki Takashima ◽  
Masaki Ito ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Gas Phase ◽  
Phase Structure ◽  
Steric Effects ◽  
Tert Butyl ◽  
Theoretical Investigations ◽  
Gas Phase Structure

The Impact of the Aqueous Phase Chemistry of HNO4 on Gas Phase Tropospheric Chemistry

2001 ◽  
Vol 32 ◽  
pp. 269-270
Author(s):  
J.E. WILLIAMS ◽  
F.J. DENTENER ◽  
A.R. van den BERG
Keyword(s):  
Gas Phase ◽  
Aqueous Phase ◽  
Tropospheric Chemistry ◽  
Phase Chemistry ◽  
The Impact

scholarly journals Explicit modeling of volatile organic compounds partitioning in the atmospheric aqueous phase

2013 ◽  
Vol 13 (2) ◽  
pp. 1023-1037 ◽  
Author(s):  
C. Mouchel-Vallon ◽  
P. Bräuer ◽  
M. Camredon ◽  
R. Valorso ◽  
S. Madronich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Content ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Water Soluble ◽  
Chemical Mechanism ◽  
Organic Species ◽  
Cloud Water Content ◽  
Isoprene Oxidation

Abstract. The gas phase oxidation of organic species is a multigenerational process involving a large number of secondary compounds. Most secondary organic species are water-soluble multifunctional oxygenated molecules. The fully explicit chemical mechanism GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere) is used to describe the oxidation of organics in the gas phase and their mass transfer to the aqueous phase. The oxidation of three hydrocarbons of atmospheric interest (isoprene, octane and α-pinene) is investigated for various NOx conditions. The simulated oxidative trajectories are examined in a new two dimensional space defined by the mean oxidation state and the solubility. The amount of dissolved organic matter was found to be very low (yield less than 2% on carbon atom basis) under a water content typical of deliquescent aerosols. For cloud water content, 50% (isoprene oxidation) to 70% (octane oxidation) of the carbon atoms are found in the aqueous phase after the removal of the parent hydrocarbons for low NOx conditions. For high NOx conditions, this ratio is only 5% in the isoprene oxidation case, but remains large for α-pinene and octane oxidation cases (40% and 60%, respectively). Although the model does not yet include chemical reactions in the aqueous phase, much of this dissolved organic matter should be processed in cloud drops and modify both oxidation rates and the speciation of organic species.

scholarly journals Identifying precursors and aqueous organic aerosol formation pathways during the SOAS campaign

2016 ◽  
Vol 16 (22) ◽  
pp. 14409-14420 ◽  
Author(s):  
Neha Sareen ◽  
Annmarie G. Carlton ◽  
Jason D. Surratt ◽  
Avram Gold ◽  
Ben Lee ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Negative Ion ◽  
Anthropogenic Sources ◽  
Ionization Mass ◽  
Aqueous Mixtures ◽  
Aerosol Formation

Abstract. Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized, low-volatility organic aerosol and, in some cases, light-absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, and health. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented, forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols), leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify additional precursors and products that may be atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere into water at Brent, Alabama, during the 2013 Southern Oxidant and Aerosol Study (SOAS). Hydroxyl (OH⚫) radical oxidation experiments were conducted with the aqueous mixtures collected from SOAS to better understand the formation of SOA through gas-phase followed by aqueous-phase chemistry. Total aqueous-phase organic carbon concentrations for these mixtures ranged from 92 to 179 µM-C, relevant for cloud and fog waters. Aqueous OH-reactive compounds were primarily observed as odd ions in the positive ion mode by electrospray ionization mass spectrometry (ESI-MS). Ultra high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) spectra and tandem MS (MS–MS) fragmentation of these ions were consistent with the presence of carbonyls and tetrols. Products were observed in the negative ion mode and included pyruvate and oxalate, which were confirmed by ion chromatography. Pyruvate and oxalate have been found in the particle phase in many locations (as salts and complexes). Thus, formation of pyruvate/oxalate suggests the potential for aqueous processing of these ambient mixtures to form SOAAQ.

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