scholarly journals Photochemical Reactions of Uranyl Ions with Organic Compounds. II. The Mechanism of the Photo-Oxidation of Alcohols by Uranyl Ions

1970 ◽  
Vol 43 (8) ◽  
pp. 2359-2363 ◽  
Author(s):  
Shukichi Sakuraba ◽  
Ryoka Matsushima
Keyword(s):  
Organic Compounds ◽  
Photochemical Reactions ◽  
Uranyl Ions ◽  
Photo Oxidation ◽  
Oxidation Of Alcohols

scholarly journals Polar organic compounds in rural PM<sub>2.5</sub> aerosols from K-puszta, Hungary, during a 2003 summer field campaign: Sources and diel variations

2005 ◽  
Vol 5 (7) ◽  
pp. 1805-1814 ◽  
Author(s):  
A. C. Ion ◽  
R. Vermeylen ◽  
I. Kourtchev ◽  
J. Cafmeyer ◽  
X. Chi ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Malic Acid ◽  
Sampling Site ◽  
Photochemical Reactions ◽  
Oxidation Products ◽  
Forest Site ◽  
Supporting Evidence ◽  
Diel Pattern ◽  
Field Campaign ◽  
Photo Oxidation

Abstract. In the present study, we examined PM2.5 continental rural background aerosols, which were collected during a summer field campaign at K-puszta, Hungary (4 June-10 July 2003), a mixed coniferous/deciduous forest site characterized by intense solar radiation during summer. Emphasis was placed on polar oxygenated organic compounds that provide information on aerosol sources and source processes. The major components detected at significant atmospheric concentrations were: (a) photo-oxidation products of isoprene including the 2-methyltetrols (2-methylthreitol and 2-methylerythritol) and 2-methylglyceric acid, (b) levoglucosan, a marker for biomass burning, (c) malic acid, an intermediate in the oxidation of unsaturated fatty acids, and (d) the sugar alcohols, arabitol and mannitol, markers for fungal spores. Diel patterns with highest concentrations during day-time were observed for the 2-methyltetrols, which can be regarded as supporting evidence for their fast photochemical formation from locally emitted isoprene. In addition, a diel pattern with highest concentrations during day-time was observed for the fungal markers, suggesting that the release of fungal fragments that are associated with the PM2.5 aerosol is enhanced during that time. Furthermore, a diel pattern was also found for levoglucosan with the highest concentrations at night when wood burning may take place in the settlements around the sampling site. In contrast, malic acid did not show day/night differences but was found to follow quite closely the particulate and organic carbon mass. This is interpreted as an indication that malic acid is formed in photochemical reactions which have a much longer overall time-scale than that of isoprene photo-oxidation, and the sources of its precursors are manifold, including both anthropogenic and natural emissions. On the basis of the high concentrations found for the isoprene oxidation products during day-time, it can be concluded that rapid photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol (SOA) formation at K-puszta during summer.

scholarly journals Polar organic compounds in rural PM<sub>2.5</sub> aerosols from K-puszta, Hungary, during a 2003 summer field campaign: sources and diurnal variations

2005 ◽  
Vol 5 (2) ◽  
pp. 1863-1889 ◽  
Author(s):  
A. C. Ion ◽  
R. Vermeylen ◽  
I. Kourtchev ◽  
J. Cafmeyer ◽  
X. Chi ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Malic Acid ◽  
Photochemical Reactions ◽  
Oxidation Products ◽  
Forest Site ◽  
Diurnal Pattern ◽  
Field Campaign ◽  
Photo Oxidation ◽  
Isoprene Oxidation ◽  
Isoprene Oxidation Products

Abstract. In the present study, we examined PM2.5 continental rural background aerosols, which were collected during a summer field campaign at K-puszta, Hungary (4 June–10 July 2003), a mixed coniferous/deciduous forest site characterized by intense solar radiation during summer. Emphasis was placed on polar oxygenated organic compounds that provide information on aerosol sources and source processes. Analysis was performed using gas chromatography/mass spectrometry (GC/MS) after suitable sample workup consisting of extraction with methanol and derivatisation into trimethylsilyl (TMS) derivatives. The major components detected at significant atmospheric concentrations were: (a) photo-oxidation products of isoprene including the 2-methyltetrols (2-methylthreitol and 2-methylerythritol) and 2-methylglyceric acid, (b) levoglucosan, a marker for biomass burning, (c) malic acid, an end-oxidation product of unsaturated fatty acids, and (d) the sugar alcohols, arabitol and mannitol, markers for fungal spores. Diurnal patterns with highest concentrations during day-time were observed for the isoprene oxidation products, i.e., the 2-methyltetrols and 2-methylglyceric acid, which can be regarded as supporting evidence for their fast photochemical formation from their locally emitted precursor. In addition, a diurnal pattern with highest concentrations during day-time was observed for the fungal markers, arabitol and mannitol, suggesting that the release of fungal fragments that are associated with the PM2.5 aerosol is enhanced during that time. Furthermore, a diurnal pattern was also found for levoglucosan with the highest concentrations at night when wood burning may take place in the settlements around the sampling site. In contrast, malic acid did not show day/night differences but was found to follow quite closely the particulate and organic carbon mass. This is interpreted as an indication that malic acid is formed in photochemical reactions which have a much longer overall time-scale than that of isoprene photo-oxidation, and the sources of its precursors are manifold, including both anthropogenic and natural emissions. On the basis of the high concentrations found for the isoprene oxidation products, i.e., the 2-methyltetrols (28.5 ng m-3) and 2-methylglyceric acid (7.6 ng m-3), it can be concluded that rapid photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol (SOA) formation at K-puszta during summer.

LED Light Sources in Organic Synthesis: An Entry to A Novel Approach

2021 ◽  
Vol 18 ◽  
Author(s):  
Aparna Das
Keyword(s):  
Organic Compounds ◽  
Organic Synthesis ◽  
Photochemical Reaction ◽  
Low Cost ◽  
Environmentally Friendly ◽  
Photochemical Reactions ◽  
Light Sources ◽  
Blue Led ◽  
Oxidation Reduction ◽  
Novel Approach

: In recent years, photocatalytic technology has shown great potential as a low-cost, environmentally friendly, and sustainable technology. Compared to other light sources in photochemical reaction, LEDs have advantages in terms of efficiency, power, compatibility, and environmentally-friendly nature. This review highlights the most recent advances in LED-induced photochemical reactions. The effect of white and blue LEDs in reactions such as oxidation, reduction, cycloaddition, isomerization, and sensitization is discussed in detail. No other reviews have been published on the importance of white and blue LED sources in the photocatalysis of organic compounds. Considering all the facts, this review is highly significant and timely.

Photo-oxidation of alcohols catalysed by platinised titanium dioxide

1984 ◽  
Vol 25 (31) ◽  
pp. 3363-3364 ◽  
Author(s):  
Falah H. Hussein ◽  
Gerald Pattenden ◽  
Robert Rudham ◽  
James J. Russell
Keyword(s):  
Titanium Dioxide ◽  
Photo Oxidation ◽  
Oxidation Of Alcohols
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