The vacuum ultraviolet photolysis of hydrogen chloride. The role of the hot hydrogen atoms

The vacuum u.v. photolysis of trimethylethylene (2-methyl-2-butene) was carried out in a static system using rare gas resonance lamps: xenon (147.0 nm) and krypton (123.6 nm). The main hydrocarbon products were isoprene, 1,3-butadiene, propyne, allène, ethylene, and other minor products. Identification and measurements of the yields of hydrogen atoms, methyl, and ethyl radicals were carried out quantitatively by the use of radical–radical reactions. Because of the high yield of isoprene, the effect of conversion was studied. At a high conversion (i.e. 0.1%) the isoprene quantum yield decreases. Hydrogen atoms add mainly to the secondary carbon of the monomer (≥90%). The Δ(CH3,tert-C5H11) value was calculated to be 1.32 ± 0.14. With the krypton line (10.0 eV) no evidence was found for the participation of ionic reactions in the formation of the measured products except for the formation of 2-methyl-1-butene in a low yield. At this wavelength the ion quantum yield is 0.224 ± 0.005.

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The reaction of hydrogen atoms with 1-butanethiol and thiolane the role of chemically activated 1-butanethiol

International Journal of Chemical Kinetics ◽

10.1002/kin.550101004 ◽

1978 ◽

Vol 10 (10) ◽

pp. 1043-1054 ◽

Cited By ~ 9

Author(s):

Osamu Horie ◽

Junya Nishino ◽

Akira Amano

Keyword(s):

Hydrogen Atoms

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Time-resolved fluorescence measurements of KrF emission produced by vacuum ultraviolet photolysis of KrF2 and Kr/F2 mixtures

Physica Scripta ◽

10.1088/0031-8949/41/1/018 ◽

1990 ◽

Vol 41 (1) ◽

pp. 71-74 ◽

Cited By ~ 1

Author(s):

J J Tiee ◽

C R Quick ◽

A H Hsu ◽

D E Hof

Keyword(s):

Vacuum Ultraviolet ◽

Time Resolved Fluorescence ◽

Time Resolved ◽

Fluorescence Measurements ◽

Ultraviolet Photolysis

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PHOTOCHEMICAL SEPARATION OF MERCURY ISOTOPES: III. THE REACTION OF Hg2026(3P1) ATOMS, PHOTOEXCITED IN NATURAL MERCURY VAPOR, WITH HYDROGEN CHLORIDE

Canadian Journal of Chemistry ◽

10.1139/v59-127 ◽

1959 ◽

Vol 37 (5) ◽

pp. 930-939 ◽

Cited By ~ 9

Author(s):

C. C. McDonald ◽

J. R. McDowell ◽

H. E. Gunning

Keyword(s):

Emission Line ◽

Hydrogen Chloride ◽

Mercury Vapor ◽

Pure Hydrogen ◽

Hydrogen Atoms ◽

Unsaturated Compounds ◽

Depletion Effect ◽

Flowing Hydrogen ◽

Fast Flow ◽

Static Conditions

An investigation has been made of the reaction of Hg2026(3P1) atoms, photoexcited in natural mercury vapor, with flowing hydrogen chloride at 28–30 °C. Emphasis has been placed on the effect of reaction parameters on the Hg202 content of the calomel product of the reaction.Under fast-flow conditions it has been found that the calomel product contains 44% Hg202, corresponding to an enrichment of 48% over the normal abundance of 29.8%.In the presence of unsaturated compounds such as butadiene and benzene the enrichment is markedly increased. With butadiene and benzene as addends, the maximum enrichments were 98% and 85% respectively.The reaction with pure hydrogen chloride can be explained in terms of the sequence:[Formula: see text]where HgN is natural mercury and M is a third body, including the wall.In the presence of unsaturated compounds (U), additional reactions are postulated to occur:[Formula: see text]The increased enrichment in the presence of unsaturated addends is explained by the reduced rate of formation of HgNCl through cleanup of chlorine and hydrogen atoms by reactions [6] and [7].Under static conditions, the pure hydrogen chloride reaction formed a calomel product of normal Hg202 abundance. This finding is explained as a localized depletion of the unexcited mercury in Hg202, through reaction [1]. With increasing linear flow rate the depletion effect gradually disappears and enrichments maximize at high flow rates.The Hg202 enrichment was found to be very sensitive to the wall temperature of the Hg202 source. In a 50:50 v/v mixture of hydrogen chloride and butadiene the enrichment was found to decrease from 68% to 24% as the lamp temperature was raised from 25.5 °C to 50 °C. The effect is explained by temperature broadening of the emission line leading to overlap of the emission line on absorption contours adjacent to that of Hg202.Both the rate of deposition of the calomel product and the Hg202 enrichment were found to depend upon the concentration of natural mercury in the gas stream for hydrogen chloride – butadiene mixtures. Optimum conditions corresponded to a slight supersaturation of the stream with mercury vapor.

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