Singlet industrialized oxygenation

The photooxidation of cyclopentadiene by singlet oxygen is one step of an industrial process to make 2-cyclopentene-l, 4-diol [40]. Hence the driver is a commercial one, namely to develop a continuous synthesis of this molecule. 

This reachon, of industrial interest, utilizes singlet oxygen generated by irradiation in the presence of Rose Bengal [40]. An endoperoxide is formed as intermediate which is converted to 2-cyclopentene-l,4-diol by reduchon with thiourea. 

Cyclic siloxanes are important precursors in the silicon industry, being formally dimers or trimers of silanone (R2Si=0), a known intermediate. Cyclic siloxanes have been synthesized by four routes, the conventional methods being the condensation of silanediol or the hydrolysis of species such as halosilanes or aminosilanes (Scheme l)16-20. Alternatively, oxidation of disilene by triplet oxygen (equation l)21-27 or oxidation of oxadisiliranes by singlet oxygen (equation 2)28-31 may be utilized. 

Photochemical oxidants are mainly produced during power generation, in industrial operations and are also from natural sources. The singlet oxygen (3-6) is to alargeextent related to automobile exhaust, which is the main cause of the photochemical smog in the Los Angeles area. 

Singlet oxygen is involved in many important chemical processes and photochemical applications, including photodynamic therapy (Special Topic 6.23), photocarcinogeneity (Special Topic 6.7) and phototoxicity (Special Topic 6.22), chemiluminescence (Section 5.6), atmospheric photochemistry (Special Topic 6.21), polymer degradation (Special Topic 6.13), photosynthesis1389 (Special Topic 6.25) or industrial organic synthesis (Special Topic 6.20). 

In summaiy, organic ozone chemistry is an active research area and will continue to see new developments both from theoretical and industrial viewpoints. In particular, we shall likely see the relationship between ozone chemistry, autoxidation, photo-oxidation, and singlet oxygen chemistry more clearly defined, with a noteworthy contribution being made at this symposium. 

Industrial Prospects for the Chemical and Photochemical Singlet Oxygenation of Organic Compounds... 

I 22 Industrial Prospects for Chemical and Photochemical Singlet Oxygenation... 

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