scholarly journals Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase

2015 ◽  
Vol 15 (1) ◽  
pp. 495-503 ◽  
Author(s):  
N. T. Tsona ◽  
N. Bork ◽  
H. Vehkamäki
Keyword(s):  
Relative Humidity ◽  
Gas Phase ◽  
Reaction Rate ◽  
Kinetic Modelling ◽  
Reaction Rate Constant ◽  
Phase Reaction ◽  
So2 Oxidation ◽  
Cluster Ion ◽  
Anionic Cluster ◽  
Sulfate Radical Anion

Abstract. The gas phase reaction between SO4−(H2O)n and SO2, n = 0–2, is investigated using ab initio calculations and kinetic modelling. Structures of reactants, transition states and products are reported. Our calculations predict that the SO2SO4−(H2O)n cluster ion, which is formed upon SO2 and SO4−(H2O)n collision, can isomerize to SO3SO3−(H2O)n. The overall reaction is SO2 oxidation by the SO4−(H2O)n anionic cluster. The results show that SO4−(H2O)n is a good SO2 oxidant, especially at low relative humidity, with a reaction rate constant up to 1.5 × 10−10 cm3 molecule−1s−1. At high relative humidity, instead, the re-evaporation of SO2 from the SO2SO

scholarly journals Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase

2014 ◽  
Vol 14 (9) ◽  
pp. 12863-12886
Author(s):  
N. T. Tsona ◽  
N. Bork ◽  
H. Vehkamäki
Keyword(s):  
Relative Humidity ◽  
Gas Phase ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Phase Reaction ◽  
So2 Oxidation ◽  
Gas Phase Reaction ◽  
Cluster Ion ◽  
Anionic Cluster ◽  
Sulfate Radical Anion

Abstract. The gas phase reaction between SO4−(H2O)n and SO2, n = 0–2, is investigated using ab initio calculations and kinetic modeling. Structures of reactants, transition states and products are reported. Our calculations predict that the SO2SO4−(H2O)n cluster ion, formed upon SO2 and SO4−(H2O)n collision, can isomerize to SO3SO3−(H2O)n. The overall reaction is SO2 oxidation by the SO4−(H2O)n anionic cluster. The results show that SO4−(H2O)n is a good SO2 oxidant, especially at low relative humidity, with a~reaction rate constant up to 1.1 × 10−10 cm3 molecule−1 s−1. At high relative humidity, instead, the re-evaporation of SO2 from the SO2SO4−(H2O)n cluster ion is favoured.

Reaction rate constant of SO3+ NH3in the gas phase

1990 ◽  
Vol 95 (D9) ◽  
pp. 13981 ◽  
Author(s):  
Gaunlin Shen ◽  
Masako Suto ◽  
L. C. Lee
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant

scholarly journals Laboratory study on heterogeneous decomposition of methyl chloroform on various standard aluminosilica clay minerals as a potential tropospheric sink

2003 ◽  
Vol 3 (2) ◽  
pp. 1843-1891
Author(s):  
S. Kutsuna ◽  
L. Chen ◽  
O. Ohno ◽  
N. Negishi ◽  
K. Takeuchi ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Clay Minerals ◽  
Reaction Rate ◽  
Ground Surface ◽  
Reaction Rate Constant ◽  
Pseudo First Order Reaction ◽  
Dry Air ◽  
Reaction Rate Constants ◽  
Methyl Chloroform ◽  
Bet Equation

Abstract. Methyl chloroform (1,1,1-trichloroethane, CH3CCl3) was found to decompose heterogeneously on seven types of standard clay minerals (23 materials) in dry air at 313 K in the laboratory. All reactions proceeded through the elimination of HCl; CH3CCl3 was converted quantitatively to CH2=CCl2. The activities of the clay minerals were compared via their pseudo-first-order reaction rate constants (k1). A positive correlation was observed between the k1 value and the specific surface area (S) of clay minerals, where the S value was determined by means of the general Brunauer-Emmett-Teller (BET) equation. The k1 value was anti-correlated with the value of n, a parameter of the general BET equation, and correlated with the water content that can be removed easily from the clay minerals. The reaction required no special pretreatment of clay minerals, such as heating at high temperatures; hence, the reaction can be expected to occur in the environment. Photoillumination by wavelengths present in the troposphere did not accelerate the decomposition of CH3CCl3, but it induced heterogeneous photodecomposition of CH2=CCl2. The temperature dependence of k1, the adsorption constants of CH3CC3 and CH2=CCl2, and a surface reaction rate constant were determined for an illite sample. The k1 value increased with increasing temperature. The amount of CH3CCl3 adsorbed on the illite during the reaction was proportional to the partial pressure of CH3CCl3. The reaction was sensitive to relative humidity and the k1 value decreased with increasing relative humidity. However, the reaction was found to proceed at a relative humidity of 22% at 313 K, although the k1 value was about one-twentieth of the value in dry air. The conditions required for the reaction may be present in major desert regions of the world. A simple estimation indicates that the possible heterogeneous decomposition of CH3CC3 on the ground surface in arid regions is worth taking into consideration when inferring the tropospheric lifetime of CH3CC3 and global OH concentration from the global budget concentration of CH3CCl3.

scholarly journals Low temperature gas phase reaction rate coefficient measurements: Toward modeling of stellar winds and the interstellar medium

2019 ◽  
Vol 15 (S350) ◽  
pp. 382-383
Author(s):  
Niclas A. West ◽  
Edward Rutter ◽  
Mark A. Blitz ◽  
Leen Decin ◽  
Dwayne E. Heard
Keyword(s):  
Low Temperature ◽  
Interstellar Medium ◽  
Gas Phase ◽  
Low Temperatures ◽  
Reaction Rate ◽  
Rate Coefficient ◽  
Building Blocks ◽  
Rate Coefficients ◽  
Stellar Winds ◽  
Phase Reaction

AbstractStellar winds of Asymptotic Giant Branch (AGB) stars are responsible for the production of ∼85% of the gas molecules in the interstellar medium (ISM), and yet very few of the gas phase rate coefficients under the relevant conditions (10 – 3000 K) needed to model the rate of production and loss of these molecules in stellar winds have been experimentally measured. If measured at all, the value of the rate coefficient has often only been obtained at room temperature, with extrapolation to lower and higher temperatures using the Arrhenius equation. However, non-Arrhenius behavior has been observed often in the few measured rate coefficients at low temperatures. In previous reactions studied, theoretical simulations of the formation of long-lived pre-reaction complexes and quantum mechanical tunneling through the barrier to reaction have been utilized to fit these non-Arrhenius behaviours of rate coefficients.Reaction rate coefficients that were predicted to produce the largest change in the production/loss of Complex Organic Molecules (COMs) in stellar winds at low temperatures were selected from a sensitivity analysis. Here we present measurements of rate coefficients using a pulsed Laval nozzle apparatus with the Pump Laser Photolysis - Laser Induced Fluorescence (PLP-LIF) technique. Gas flow temperatures between 30 – 134 K have been produced by the University of Leeds apparatus through the controlled expansion of N2 or Ar gas through Laval nozzles of a range of Mach numbers between 2.49 and 4.25.Reactions of interest include those of OH, CN, and CH with volatile organic species, in particular formaldehyde, a molecule which has been detected in the ISM. Kinetics measurements of these reactions at low temperatures will be presented using the decay of the radical reagent. Since formaldehyde and the formal radical (HCO) are potential building blocks of COMs in the interstellar medium, low temperature reaction rate coefficients for their production and loss can help to predict the formation pathways of COMs observed in the interstellar medium.

ABSORBSI H2S MENGGUNAKAN LARUTAN Fe-EDTA DALAM PACKED COLUMN

EKUILIBIUM ◽  
2011 ◽  
Vol 10 (2) ◽  
Author(s):  
Endang Kwartiningsih ◽  
Arif Jumari
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Phase ◽  
Reaction Rate ◽  
Packed Column ◽  
Reaction Rate Constant ◽  
Absorption Process ◽  
Edta Solution

<p><strong><em>Abstract:</em></strong><strong><em> </em></strong><em>Gas purification from the content of H<sub>2</sub>S using  Fe-EDTA (Iron Chelated Solution) gave  several advantages. The advantages were  the absorbent solution can be regenerated that means  a cheap operation cost,  the separated sulfur was a solid that is easy to handle and is save to be disposal to environment. This research was done by simulation and experimental. The simulation step was done by mathematical model arrangement representing the absorption process in packed column through mass transfer arrangement such as mass transfer equations and chemical reaction. The experimental step was done with the making of Fe-EDTA solution from FeCl<sub>2</sub> and EDTA. Then Fe-EDTA solution was flown in counter current packed column that was contacted with H<sub>2</sub>S in the methane gas. By comparing gas composition result of experiment and simulation, the value of mass transfer coefficient in gas phase ( k<sub>Ag</sub>a), mass transfer coefficient in liquid phase (k<sub>Al</sub>a) and the reaction rate constant ( k) were found. The values of mass transfer coefficient in liquid phase (k<sub>Al</sub>a) were lower than values of mass transfer coefficient in gas phase (k<sub>Ag</sub>a) and the reaction rate constant (k). It meant that H<sub>2</sub>S absorption  process using Fe-EDTA absorbent solution was determined by mass transfer process in liquid phase. The higher flow rate of absorbent, the higher value of mass transfer coefficient in liquid phase. </em><em>The smaller packing diameter, the higher value of mass transfer coefficient in liquid phase.From analysis of dimension, the relation of dimensionless number between Sherwood number and flow rate of absorbent, packing diameter was</em><strong></strong></p><p> <strong><em>Keywords:</em></strong><strong><em> </em></strong><em>chemical reaction, Fe-EDTA, H<sub>2</sub>S absorption, mass transfer</em></p>

Gas-phase reaction rate of sodium hydroxide with hydrochloric acid

1984 ◽  
Vol 88 (14) ◽  
pp. 3123-3129 ◽  
Author(s):  
J. A. Silver ◽  
A. C. Stanton ◽  
M. S. Zahniser ◽  
C. E. Kolb
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Gas Phase ◽  
Reaction Rate ◽  
Phase Reaction ◽  
Gas Phase Reaction
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