Stochastic and network analysis of polycyclic aromatic growth in a coflow diffusion flame

2021 ◽  
Vol 23 (7) ◽  
pp. 4326-4333
Author(s):  
Jacob C. Saldinger ◽  
Paolo Elvati ◽  
Angela Violi
Keyword(s):  
Network Analysis ◽  
Gas Phase ◽  
Diffusion Flame ◽  
Polycyclic Aromatic ◽  
Phase Variations ◽  
Coflow Diffusion Flame

An important step in predicting the growth of soot nanoparticles is understanding how gas phase variations affect the formation of their aromatic precursors.

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

scholarly journals Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

2014 ◽  
Vol 14 (13) ◽  
pp. 19395-19429
Author(s):  
L. Zhang ◽  
I. Cheng ◽  
D. Muir ◽  
J.-P. Charland
Keyword(s):  
Gas Phase ◽  
Aromatic Compounds ◽  
Oil Sands ◽  
Polycyclic Aromatic Compounds ◽  
Particulate Phase ◽  
Athabasca Oil Sands ◽  
Polycyclic Aromatic ◽  
Alkylated Pahs ◽  
Snow Samples ◽  
Air Concentrations

Abstract. Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout) ratios (Wt) for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3–184.9 (chrysene) ng L−1 and 0.01–3.9 (naphthalene) ng m−3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3–646.7 (C3-fluoranthene/pyrene) ng L−1 and 0.21–16.9 (C3-naphthalene) ng m−3, respectively, for alkylated PAHs, and 8.5–530.5 (C4-dibenzothiophene) ng L−1 and 0.13–6.6 (C2-dibenzothiophene) ng m−3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100–1.1 × 106 from snow scavenging and 350–2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2–7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14–20 times greater than gas-phase dominant PACs in snow samples and 7–20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater than rain scavenging for particulate-phase dominant PACs and 4–9.6 times greater than rain scavenging for gas-phase dominant PACs. Gas-particle fractions of each PAC, particle size distributions of particulate-phase dominant PACs, and Henry's Law constant of gas-phase dominant PACs explained, to a large extent, the different Wt values among the different PACs and precipitation types. This study verified findings from a previous study of Wang et al. (2014) which suggested that snow scavenging is more efficient than rain scavenging of particles for equivalent precipitation amount, and also provided new knowledge on the scavenging of gas-phase PACs by snow and rain.

Computational and experimental study of a forced, time-dependent, methane–air coflow diffusion flame

2007 ◽  
Vol 31 (1) ◽  
pp. 971-978 ◽  
Author(s):  
S.B. Dworkin ◽  
B.C. Connelly ◽  
A.M. Schaffer ◽  
B.A.V. Bennett ◽  
M.B. Long ◽  
...  
Keyword(s):  
Experimental Study ◽  
Diffusion Flame ◽  
Time Dependent ◽  
Coflow Diffusion Flame

scholarly journals Study of passive sampling of polycyclic aromatic hydrocarbons in gas phase using Amberlite XAD resins as filling materials of semipermeable membranes

2013 ◽  
Vol 110 ◽  
pp. 494-500 ◽  
Author(s):  
Luis Gustavo T. dos Reis ◽  
Daniel Gallart-Mateu ◽  
Wagner F. Pacheco ◽  
Agustín Pastor ◽  
Miguel de la Guardia ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Gas Phase ◽  
Aromatic Hydrocarbons ◽  
Passive Sampling ◽  
Semipermeable Membranes ◽  
Filling Materials ◽  
Polycyclic Aromatic ◽  
Xad Resins
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