Maximising the efficiency of continuous photo-oxidation with singlet oxygen in supercritical CO2 by use of fluorous biphasic catalysis

2012 ◽  
Vol 48 (25) ◽  
pp. 3073 ◽  
Author(s):  
Jessica F. B. Hall ◽  
Xue Han ◽  
Martyn Poliakoff ◽  
Richard A. Bourne ◽  
Michael W. George
Keyword(s):  
Singlet Oxygen ◽  
Supercritical Co2 ◽  
Biphasic Catalysis ◽  
Photo Oxidation ◽  
Fluorous Biphasic Catalysis

Article

1998 ◽  
Vol 76 (12) ◽  
pp. 1805-1816
Author(s):  
L Ross C Barclay ◽  
Jennifer K Grandy ◽  
Heather D MacKinnon ◽  
Heather C Nichol ◽  
Melinda R Vinqvist
Keyword(s):  
Oxygen Uptake ◽  
Singlet Oxygen ◽  
Sodium Azide ◽  
Lignin Content ◽  
Sodium Dodecyl ◽  
Kinetic Studies ◽  
Product Distribution ◽  
Geometrical Isomers ◽  
Photo Oxidation ◽  
Tert Butyl

3,5-Di-tert-butyl-ortho-quinone, 6, and 1-(3,4-dimethoxyphenyl-2-(2-methoxyphenoxy)-1-propanone, 7, models for oxidized lignin and for lignin, were used as sensitizers of photo-oxidation. Product studies by HPLC from oxidation of methyl linoleate in solution sensitized by 6 or 7, and in sodium dodecyl sulfate (SDS) sensitized by 6, showed a product distribution of six hydroperoxides, the four conjugated 9- and 13-hydroperoxides of the geometrical isomers: trans-10, cis-12 (2), cis-9, trans-11 (3), trans-10, trans-12 (4), and trans-9, trans-11 (5)-octadecadienoates plus two nonconjugated hydroperoxides. The higher cis/trans to trans/trans (ct/tt) of geometrical isomers (2 + 3//4 + 5) compared to ct/tt from known thermal free-radical peroxidations (Type 1) indicate that singlet oxygen (Type 2) oxidation occurs in reactions sensitized by 6 or 7. Kinetic studies by oxygen uptake are reported on oxidations of hydrocarbons 1-phenyl-2-methylpropene,8, and trans-stilbene,9, sensitized by the quinone, 6, or by a dye, Rose Bengal. Quenching studies imply singlet oxygen reactions. Milled wood lignin undergoes self-initiated photo-oxidation in water, and oxygen uptake was quenched by sodium azide. Cellobiose, a cellulose model, undergoes sensitized photo-oxidation using model quinone, 6, in a mixture of tert-butyl alcohol and water or using the sensitizers benzophenone or the lignin model, 7, delivered on a solid support, silica gel, and these oxidations were quenched with sodium azide. These results implicate singlet oxygen in the photo-yellowing of high lignin content wood pulps.Key words: lignin models, ortho-quinone, photo-oxidation, singlet oxygen, lignin, cellobiose.

Production of 5-hydroxy-4-keto-2-pentenoic acid by photo-oxidation of 5-hydroxymethylfurfural with singlet oxygen: A kinetic investigation

2010 ◽  
Vol 210 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Canterino Marisa ◽  
Di Somma Ilaria ◽  
Raffaele Marotta ◽  
Andreozzi Roberto ◽  
Caprio Vincenzo
Keyword(s):  
Singlet Oxygen ◽  
Kinetic Investigation ◽  
Photo Oxidation

Photosensitized oxidation of 9,10-dimethylanthracene with singlet oxygen by using a safranin O/silica composite under visible light

2015 ◽  
Vol 14 (3) ◽  
pp. 597-602 ◽  
Author(s):  
Elim Albiter ◽  
Salvador Alfaro ◽  
Miguel A. Valenzuela
Keyword(s):  
Visible Light ◽  
Singlet Oxygen ◽  
Second Step ◽  
Homogeneous Reaction ◽  
Photosensitized Oxidation ◽  
Photo Oxidation ◽  
The Third ◽  
Silica Composite ◽  
Safranin O

The photo-oxidation of DMA could be carried out in 3 steps: the first step is the photosensitized production of 1O2 near the surface of the composite; the second step is the diffusion of 1O2 from the surroundings of the surface to the solvent and the third step is the homogeneous reaction between 1O2 and DMA.

New bis(fluoro-ponytailed) bipyridine ligands for Pd-catalyzed Heck reactions under fluorous biphasic catalysis condition

Tetrahedron ◽  
2007 ◽  
Vol 63 (9) ◽  
pp. 2019-2023 ◽  
Author(s):  
Norman Lu ◽  
Yan-Chou Lin ◽  
Jeng-Yung Chen ◽  
Chi-Wen Fan ◽  
Ling-Kang Liu
Keyword(s):  
Heck Reactions ◽  
Biphasic Catalysis ◽  
Catalysis Condition ◽  
Fluorous Biphasic Catalysis

Dye-sensitized photo-oxidation of thiourea by singlet oxygen

1991 ◽  
Vol 60 (1) ◽  
pp. 47-50 ◽  
Author(s):  
V.K. Vaidya ◽  
R.L. Pitlia ◽  
B.V. Kabra ◽  
S.L. Mali ◽  
Suresh C. Ameta
Keyword(s):  
Singlet Oxygen ◽  
Photo Oxidation ◽  
Dye Sensitized
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