The vacuum UV photolysis of various C4 and C5 olefins: The energy content of the ?- and ?-methallyl fragments

1980 ◽  
Vol 12 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Guy J. Collin ◽  
H�l�ne Deslauriers
Keyword(s):  
Energy Content ◽  
Uv Photolysis ◽  
Vacuum Uv

La photochimie du cis-penta-1,3-diène, en phase gazeuse à 184,9 et 147,0 nm

1991 ◽  
Vol 69 (8) ◽  
pp. 1245-1251
Author(s):  
Guy J. Collin ◽  
Hélène Deslauriers ◽  
George R. De Maré
Keyword(s):  
Key Words ◽  
Energy Content ◽  
Phase Gazeuse ◽  
Radical Scavenger ◽  
Methyl Radical ◽  
Hydrogen Atoms ◽  
Lower Yield ◽  
Uv Photolysis ◽  
Vacuum Uv

We have studied the 184.9 and 147.0 nm photochemistry of gaseous cw-1,3-pentadiene: the main products observed at 184.9 nm are trans-1,3-pentadiene and 1,3-cyclopentadiene. The formation of radicals also occurs as shown through the use of DI as a radical scavenger. Cyclopentadiene is the likely product of successive eliminations of two hydrogen atoms from the photoexcited molecule after rearrangement of the pentadienyl radical to the cyclopentenyl structure: Ф0(cyclo-C5H6) ≈ 0.25. Elimination of a methyl radical (Ф0 ≈ 0.50) also occurs, with formation of CH2=CHCH=ĊH* and, in a lower yield, CH2=C=CHĊH2*. However, it is not possible to identify properly the mechanism of the formation of the latter radical. It may be the result of the isomerization of either the first photoexcited molecule or the excited 1,3-butadienyl radicals. A small amount of 1,4-pentadiene formation is also observed (Ф0 ≈ 0.035 ± 0.015). At 147.0 nm, the same characteristics are observed, together with higher fragmentation due to the higher energy content of the photoexcited molecules. It appears that the photofragmentation at both wavelengths is more in line with that of acyclic alkenes than with that of 1,3-butadiene, which tends to undergo isomerization of the photoexcited molecules to the 1,2-butadiene structure. Key words: 1,3-pentadiene, far UV, vacuum UV, photolysis, monomolecular, fragmentation, stabilization.

scholarly journals Degradation and transformation of natural organic matter accountable for disinfection byproduct formations by UV photolysis and UV/chlor(am)ine

2018 ◽  
Vol 79 (5) ◽  
pp. 929-937 ◽  
Author(s):  
Chanathip Hirun-Utok ◽  
Songkeart Phattarapattamawong
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Low Pressure ◽  
Haloacetic Acid ◽  
Uv Photolysis ◽  
Disinfection Byproduct ◽  
Proportional Relationship ◽  
Vacuum Uv ◽  
Potential Use

Abstract This research aimed to investigate the degradation of natural organic matter responsible for the formation of trihalomethane (THM), haloacetic acid (HAA) and haloacetonitrile (HAN) during ultraviolet (UV) photolysis and a co-exposure of UV with chlorine (UV/chlorine) and chloramine (UV/chloramine). Low pressure UV (LPUV) and vacuum UV (VUV) lamps were used for photolysis. VUV and LPUV irradiation changed aromatic/unsaturated structures to aliphatic ones, resulting in decreased THM and HAN formation. Following irradiation for 60 min, LPUV decreased THM and HAN by 16% ± 2% and 20% ± 6%, respectively. VUV decreased THM and HAN formation by 23% ± 3% and 20% ± 8%, respectively. HAA formation increased following photolysis. UV/chlorine treatment decreased THM, HAA and HAN. Higher chlorine doses had an inversely proportional relationship with THM and HAN formation. A chlorine dose of 4 mg·L−1 led to the greatest reductions, corresponding to 42% ± 2%, 10% ± 10% and 18% ± 6% for THM, HAA and HAN, respectively. UV/chloramine decreased the formation of THM more than UV/chlorine. With a chloramine dose of 4 mg·L−1, THM, HAA and HAN formation decreased by 74% ± 10%, 10% ± 10% and 11% ± 10%, respectively. This study showed the potential use of UV/chlor(am)ine for controlling the formation of THM, HAA and HAN.

Quantum yields for the production of O(1S), N(2D), and N2(A 3Σ+u) from the vacuum uv photolysis of N2O

1975 ◽  
Vol 62 (11) ◽  
pp. 4266-4273 ◽  
Author(s):  
G. Black ◽  
R. L. Sharpless ◽  
T. G. Slanger ◽  
D. C. Lorents
Keyword(s):  
Quantum Yields ◽  
Uv Photolysis ◽  
Vacuum Uv

Vacuum UV photolysis of n-1-hexene and 4-methyl-1-pentene

1980 ◽  
Vol 12 (3) ◽  
pp. 249-261 ◽  
Author(s):  
Hélène Deslauriers ◽  
Guy J. Collin
Keyword(s):  
Uv Photolysis ◽  
Vacuum Uv

Vacuum uv photolysis of N2O

1974 ◽  
Vol 61 (7) ◽  
pp. 2857-2859 ◽  
Author(s):  
M. J. McEwan ◽  
G. M. Lawrence ◽  
H. M. Poland
Keyword(s):  
Uv Photolysis ◽  
Vacuum Uv

The vacuum UV photolysis of 1-butyne

1981 ◽  
Vol 17 (1) ◽  
pp. 32-33
Author(s):  
G.J. Collin
Keyword(s):  
Uv Photolysis ◽  
Vacuum Uv

Rare‐Gas‐Sensitized Vacuum uv Photolysis of Some Aliphatic Hydrocarbons

1966 ◽  
Vol 44 (1) ◽  
pp. 420-422 ◽  
Author(s):  
Günther von Bünau ◽  
Ralph N. Schindler
Keyword(s):  
Aliphatic Hydrocarbons ◽  
Rare Gas ◽  
Uv Photolysis ◽  
Vacuum Uv
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