scholarly journals Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules

2014 ◽  
Vol 118 (49) ◽  
pp. 11555-11571 ◽  
Author(s):  
Theodora Nah ◽  
Haofei Zhang ◽  
David R. Worton ◽  
Christopher R. Ruehl ◽  
Benjamin B. Kirk ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Organic Molecules ◽  
Heterogeneous Reaction ◽  
Isomeric Product

The role of alkoxy radicals in the heterogeneous reaction of two structural isomers of dimethylsuccinic acid

2015 ◽  
Vol 17 (38) ◽  
pp. 25309-25321 ◽  
Author(s):  
Chiu Tung Cheng ◽  
Man Nin Chan ◽  
Kevin R. Wilson
Keyword(s):  
Molecular Weight ◽  
Hydroxyl Radicals ◽  
Heterogeneous Reaction ◽  
Methyl Groups ◽  
Structural Isomers ◽  
Alkoxy Radicals ◽  
Weight Growth ◽  
Bond Scission

The heterogeneous reaction of hydroxyl radicals with two isomers of dimethylsuccinic acid is used to explore how the location of branched methyl groups controls C–C bond scission and molecular weight growth reactions.

scholarly journals Hydroxyl radical reactivity at the air-ice interface

2009 ◽  
Vol 9 (5) ◽  
pp. 20881-20911 ◽  
Author(s):  
T. F. Kahan ◽  
R. Zhao ◽  
D. J. Donaldson
Keyword(s):  
Aqueous Solution ◽  
Hydroxyl Radicals ◽  
Natural Waters ◽  
Heterogeneous Reaction ◽  
Radical Reactivity ◽  
Quasi Liquid Layer ◽  
Polycyclic Aromatic ◽  
Nitrite Nitrate ◽  
Spectroscopic Probe

Abstract. Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at the air-ice interface, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH) anthracene at the air-water interface, but no loss was observed at the air-ice interface. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL) that exists at the air-ice interface.

A New Approach to Determining Gas-Particle Reaction Probabilities and Application to the Heterogeneous Reaction of Deliquesced Sodium Chloride Particles with Gas-Phase Hydroxyl Radicals

2006 ◽  
Vol 110 (36) ◽  
pp. 10619-10627 ◽  
Author(s):  
Alexander Laskin ◽  
Hai Wang ◽  
William H. Robertson ◽  
James P. Cowin ◽  
Michael J. Ezell ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Heterogeneous Reaction ◽  
New Approach

scholarly journals Hydroxyl radical reactivity at the air-ice interface

2010 ◽  
Vol 10 (2) ◽  
pp. 843-854 ◽  
Author(s):  
T. F. Kahan ◽  
R. Zhao ◽  
D. J. Donaldson
Keyword(s):  
Aqueous Solution ◽  
Hydroxyl Radicals ◽  
Natural Waters ◽  
Heterogeneous Reaction ◽  
Radical Reactivity ◽  
Quasi Liquid Layer ◽  
Polycyclic Aromatic ◽  
Nitrite Nitrate ◽  
Spectroscopic Probe

Abstract. Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at air-ice interfaces, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH) anthracene at air-water interfaces, but no loss was observed at air-ice interfaces. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL) that exists at air-ice interfaces.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

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