Photo-oxidation reactions of ethylene in supercritical CO2

Koda, Seiichiro; Ebukuro, Tokuro; Otomo, Junichiro; Tsuruno, Toshihiro; Oshima, Yoshito

doi:10.1016/s1010-6030(98)00240-8

Cited by 5 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The abundance of O 2 in the atmosphere leads to light absorption of the same order of magnitude as that of O 3 in the strong ozone Hartley band (230−300 nm) region, and thus, the photochemistry of the excited O 2 should be very important. On the other hand, our study on the photoinduced partial oxidation of hydrocarbons in supercritical CO 2 suggests the formation of primary active oxygen species from O 2 when the mixture was irradiated at wavelengths longer than 242 nm. , Here, an understanding of O 2 photochemistry is also needed.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, our study on the photoinduced partial oxidation of hydrocarbons in supercritical CO 2 suggests the formation of primary active oxygen species from O 2 when the mixture was irradiated at wavelengths longer than 242 nm. 1,2 Here, an understanding of O 2 photochemistry is also needed.…”

Section: Introductionmentioning

confidence: 99%

“…The same is true for the oxidation reactions in supercritical CO 2 . In our laboratory, the property of supercritical CO 2 as the medium for the photoinduced partial oxidation of hydrocarbons was investigated. , The KrF-laser-induced oxidation of O 2 /hydrocarbon mixtures in sub- and supercritical CO 2 was studied. It was found from the irradiation of high-pressure O 2 /CO 2 mixtures that some odd-oxygen species were formed by the KrF laser irradiation, which were supposed to be responsible for the oxidation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm

2003

Self Cite

View full text Add to dashboard Cite

Laser-induced reactions of O 2 to yield ozone (O 3 ) were investigated to estimate the quantum yield of primary odd-oxygen species production from photoabsorption by O 2 as a function of excitation laser wavelength from 232 to 255 nm. The experiments were carried out at 35 °C in pressurized O 2 (2.0 MPa) and O 2 /CO 2 mixtures (9.6 MPa). The initial slope of O 3 formation versus irradiation time was used to obtain the quantum yield of the primary odd-oxygen species, minimizing possible catalytic O 3 production initiated by the subsequent photolysis of the product O 3 . The quantum yield of the primary odd-oxygen species was shown to be almost 2 in pressurized O 2 at wavelengths shorter than 242 nm, i.e., the dissociation threshold of O 2 . It was less than 2 in the O 2 /CO 2 mixture and seemed to have a tendency to increase slightly in the shorter-wavelength region. At wavelengths between 242 and 252 nm, the quantum yield decreased monotonically with increasing laser wavelength both in O 2 and in O 2 /CO 2 mixtures. It became almost 0 over the wavelength of 252 nm. These findings could not be explained by the contribution of the thermal energy of O 2 in the photodissociation process alone. Although thermal dissociation of O 2 (A, A′, c) is not ruled out on the basis of the present experiments alone, the most likely mechanism is the thermal reaction of O 2 (A, A′, c) to produce O + O 3 , taking into account the temperature dependence experiments of Shi and Barker (J. Geophys. Res. 1992, 97, 13039).

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm

2003

Self Cite

View full text Add to dashboard Cite

show abstract

“…In our previous researches, , we carried out a photoinduced partial oxidation of hydrocarbons (ethane, cyclohexane, and ethylene) in sub- and supercritical CO 2 with irradiation of pulsed KrF excimer laser at 248 nm. Although these hydrocarbons and O 2 do not absorb KrF excimer laser light under atmospheric pressure, relatively large amounts of oxidized products were formed in the mixture of hydrocarbon/O 2 /CO 2 under KrF excimer laser irradiation.…”

Section: Introductionmentioning

confidence: 99%

KrF Excimer Laser-induced Ozone Formation in Supercritical Carbon Dioxide

et al. 2000

Self Cite

View full text Add to dashboard Cite

Laser-induced reactions by a pulsed KrF excimer laser were studied using UV absorption spectroscopy in sub-and supercritical O 2 /CO 2 mixtures up to the pressure of 15 MPa (corresponding density, 17 mol dm -3 ). Although the 248 nm excimer laser photon energy is smaller than the energy required for dissociating O 2 , ozone formation was observed in O 2 /CO 2 mixtures. Under the laser irradiation, O 3 concentration increased monotonically with the increase of the irradiation time and then stayed constant, which is satisfactorily expressed by the equation d. a corresponds to O 3 formation rate and b to O 3 decomposition rate constant. The value of a increased with the increase of CO 2 density up to 3 mol dm -3 and was then kept almost constant with further increase. O 2 absorbs a photon to yield an oxygen molecule in the Herzberg III state O 2 (A′ 3 ∆ u ), being augmented along with the increase of CO 2 density. In pure O 2 , the predominant pathway of O 3 formation is the reaction between excited O 2 in Herzberg states and ground state O 2 to yield O 3 and atomic oxygen. In high-density O 2 /CO 2 mixtures, O 3 is considered to be produced through reaction between the Herzberg states O 2 and CO 2 . Taking account of the quenching effect for the above reaction together with the augmentation of O 2 absorption of laser light by the high-density CO 2 , the behavior of a with respect to CO 2 density was satisfactorily explained. The behavior of b suggested a certain inhibition of O 3 recovery in high-density CO 2 after the photodecomposition of the product O 3 , which was ascribed to the formation of CO 3 from the O( 1 D) reaction with CO 2 . A certain cage effect for the O 3 photodecomposition was also suggested. No specific pressure effect was observed near the critical point.

show abstract

Photochemical and Photo‐induced Reactions in Supercritical Fluid Solvents

Tanko¹

2010

Handbook of Green Chemistry

View full text Add to dashboard Cite

The sections in this article are Introduction “Solvent” Properties of Supercritical Fluids Scope of This Chapter Experimental Considerations Photochemical Reactions in Supercritical Fluid Solvents Geometric Isomerization Photodimerization Carbonyl Photochemistry Photosensitization and Photo‐induced Electron Transfer Photo‐oxidation Reactions Photo‐initiated Radical Chain Reactions in Supercritical Fluid Solvents Free Radical Brominations of Alkyl Aromatics in Supercritical Carbon Dioxide Free Radical Chlorination of Alkanes in Supercritical Fluid Solvents Conclusion Acknowledgment

show abstract

Photo-oxidation reactions of ethylene in supercritical CO2

Cited by 5 publications

References 8 publications

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm

KrF Excimer Laser-induced Ozone Formation in Supercritical Carbon Dioxide

Photochemical and Photo‐induced Reactions in Supercritical Fluid Solvents

Contact Info

Product

Resources

About

Photo-oxidation reactions of ethylene in supercritical CO2

Cited by 5 publications

References 8 publications

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O2 and O2/CO2 Mixtures under Irradiation from 232 to 255 nm

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O2 and O2/CO2 Mixtures under Irradiation from 232 to 255 nm

KrF Excimer Laser-induced Ozone Formation in Supercritical Carbon Dioxide

Photochemical and Photo‐induced Reactions in Supercritical Fluid Solvents

Contact Info

Product

Resources

About

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm

Wavelength Dependence of the Primary Ozone Formation in High-Pressure O₂ and O₂/CO₂ Mixtures under Irradiation from 232 to 255 nm