Arrhenius parameters for the tert-butoxy radical reactions with trimethylsilane in the gas phase

1982 ◽  
Vol 104 (23) ◽  
pp. 6445-6448 ◽  
Author(s):  
Chan Ryang Park ◽  
Se Ahn Song ◽  
Yong Eun Lee ◽  
Kwang Yul Choo
Keyword(s):  
Gas Phase ◽  
Radical Reactions ◽  
Arrhenius Parameters ◽  
Butoxy Radical

scholarly journals Cecil Edwin Henry Bawn. 6 November 1908 — 19 September 2003

2021 ◽  
Author(s):  
Richard J. Puddephatt
Keyword(s):  
Physical Chemistry ◽  
Free Radical ◽  
Gas Phase ◽  
Faculty Members ◽  
Radical Reactions ◽  
Polymer Chemistry ◽  
Diverse Group ◽  
High Explosives ◽  
Free Radical Reactions ◽  
The University

Cecil Bawn was a physical chemist with particular expertise in chemical kinetics. Early in his career he made pioneering studies of free radical reactions in the gas phase and, during the war years, on the chemistry of high explosives. From mid career, he was one of the pioneers of polymer chemistry and established and led a strong and diverse group of polymer scientists at the University of Liverpool. He was a private and enigmatic person, with a strong sense of duty. His caring and helpful attitude was greatly appreciated locally by his students and younger faculty members. Nationally, he made outstanding service contributions to physical chemistry and polymer chemistry.

Hydroxyl radical reactions in the gas phase. Products and pathways for the reaction of hydroxyl with toluene

1978 ◽  
Vol 82 (9) ◽  
pp. 1095-1096 ◽  
Author(s):  
Richard A. Kenley ◽  
John E. Davenport ◽  
Dale G. Hendry
Keyword(s):  
Hydroxyl Radical ◽  
Gas Phase ◽  
Radical Reactions

Hydroxyl radical initiated oxidation of formic acid on mineral aerosols surface: a mechanistic, kinetic and spectroscopic study

2015 ◽  
Vol 12 (2) ◽  
pp. 236 ◽  
Author(s):  
Cristina Iuga ◽  
C. Ignacio Sainz-Díaz ◽  
Annik Vivier-Bunge
Keyword(s):  
Free Radical ◽  
Formic Acid ◽  
Gas Phase ◽  
Atmospheric Aerosols ◽  
Carbonic Acid ◽  
Radical Reactions ◽  
Acid Molecule ◽  
Formyl Radical ◽  
Volatile Organic ◽  
Silicate Surface

Environmental context The presence of air-borne mineral dust containing silicates in atmospheric aerosols should be considered in any exploration of volatile organic compound chemistry. This work reports the mechanisms, relative energies and kinetics of free-radical reactions with formic acid adsorbed on silicate surface models. We find that silicate surfaces are more likely to act as a trap for organic radicals than to have a catalytic effect on their reactions. Abstract Heterogeneous reactions of atmospheric volatile organic compounds on aerosol particles may play an important role in atmospheric chemistry. Silicate particles are present in air-borne mineral dust in atmospheric aerosols, and radical reactions can be different in the presence of these mineral particles. In this work, we use quantum-mechanical calculations and computational kinetics to explore the reaction of a hydroxyl free radical with a formic acid molecule previously adsorbed on several models of silicate surfaces. We find that the reaction is slower and takes place according to a mechanism that is different than the one in the gas phase. It is especially interesting to note that the reaction final products, which are the formyl radical attached to the cluster surface, and a water molecule, are much more stable than those formed in the gas phase, the overall reaction being highly exothermic in the presence of the surface model. This suggests that the silicate surface is a good trap for the formed formyl radical. In addition, we have noted that, if a second hydroxyl radical approaches the adsorbed formyl radical, the formation of carbonic acid on the silicate surface is a highly exothermic and exergonic process. The carbonic acid molecule remains strongly attached to the surface, thus blocking CO2 formation in the formic acid oxidation reaction. The spectroscopic properties of the systems involved in the reaction have been calculated, and interesting frequency shifts have been identified in the main vibration modes.

scholarly journals Aqueous chemistry and its role in secondary organic aerosol (SOA) formation

2010 ◽  
Vol 10 (21) ◽  
pp. 10521-10539 ◽  
Author(s):  
Y. B. Lim ◽  
Y. Tan ◽  
M. J. Perri ◽  
S. P. Seitzinger ◽  
B. J. Turpin
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Base Catalysis ◽  
Radical Reactions ◽  
Oh Radicals ◽  
Aqueous Chemistry ◽  
Radical Chemistry

Abstract. There is a growing understanding that secondary organic aerosol (SOA) can form through reactions in atmospheric waters (i.e., clouds, fogs, and aerosol water). In clouds and wet aerosols, water-soluble organic products of gas-phase photochemistry dissolve into the aqueous phase where they can react further (e.g., with OH radicals) to form low volatility products that are largely retained in the particle phase. Organic acids, oligomers and other products form via radical and non-radical reactions, including hemiacetal formation during droplet evaporation, acid/base catalysis, and reaction of organics with other constituents (e.g., NH4+). This paper provides an overview of SOA formation through aqueous chemistry, including atmospheric evidence for this process and a review of radical and non-radical chemistry, using glyoxal as a model precursor. Previously unreported analyses and new kinetic modeling are reported herein to support the discussion of radical chemistry. Results suggest that reactions with OH radicals tend to be faster and form more SOA than non-radical reactions. In clouds these reactions yield organic acids, whereas in wet aerosols they yield large multifunctional humic-like substances formed via radical-radical reactions and their O/C ratios are near 1.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

Sign in / Sign up

Export Citation Format

Share Document