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

1959 ◽  
Vol 37 (5) ◽  
pp. 930-939 ◽  
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.

PHOTOCHEMICAL SEPARATION OF MERCURY ISOTOPES: IV. THE REACTION OF Hg2026(3P1) ATOMS, PHOTOEXCITED IN NATURAL MERCURY VAPOR, WITH METHYL CHLORIDE AND ISOPROPYL CHLORIDE

1959 ◽  
Vol 37 (8) ◽  
pp. 1315-1327 ◽  
Author(s):  
K. R. Osborn ◽  
H. E. Gunning
Keyword(s):  
Flow Rate ◽  
Room Temperature ◽  
Methyl Chloride ◽  
Mercury Vapor ◽  
Progressive Increase ◽  
Temperature Data ◽  
Third Body ◽  
Flow Rates ◽  
Fast Flow ◽  
Static Conditions

A detailed investigation has been made of the reaction of Hg2026(3P1) atoms, photoexcited in natural mercury vapor (HgN), with methyl chloride, at room temperature. Data are also reported on the reaction with isopropyl chloride as substrate. Hg202 enrichment in the calomel product is taken as evidence of its formation in the primary quenching reaction.Under static conditions the methyl chloride reaction was found to form calomel with the natural Hg202 abundance (29.8%). With increasing flow rate a progressive increase in Hg202 abundance was observed. Maximum enrichments were found at fast flow rates, low substrate pressures, and high values for the absorbed light intensity (IA). The most highly enriched calomel obtained in this study contained 50.4% Hg202. With increasing IA, a corresponding increase in flow rate was required to achieve maximum Hg202 enrichment. The addition of propylene or butene-1 to the methyl chloride stream was found to result in a slight decrease in Hg202 abundance over that for the pure substrate.The isotopically specific aspects of the reaction are explained in terms of the sequence:[Formula: see text]where M represents a third body, including the wall. The decrease in enrichment observed at high substrate pressures is shown to be due to Lorentz-broadening effects on the hyperfine absorption contours of HgN. The failure to obtain enrichment under static conditions is explained by the depletion in Hg202 of the HgN in the cell through reaction [1].The investigation shows that there are two primary processes operative in the mercury-6(3P1)-photosensitized decomposition of alkyl chlorides, in one of which calomel is formed. These processes presumably involve a common short-lived intermediate R—Cl—Hg.

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

1959 ◽  
Vol 37 (9) ◽  
pp. 1432-1441 ◽  
Author(s):  
J. R. McDowell ◽  
C. C. McDonald ◽  
H. E. Gunning
Keyword(s):  
Steady State ◽  
Hydrogen Chloride ◽  
Mercury Vapor ◽  
Recovery Process ◽  
Pure Hydrogen ◽  
Exchange Reactions ◽  
Recovery Techniques ◽  
Specific Step ◽  
Recovery Technique ◽  
Mercury Recovery

A further study has been made of the reaction of Hg2026(3P1) atoms, in natural mercury vapor (HgN), with hydrogen chloride under flow conditions at room temperature. Emphasis has been placed in this study on the effect of reaction parameters and mercury-recovery techniques on the Hg202 content of the solid calomel formed in the reaction.For pure hydrogen chloride the Hg202 content of the calomel was found to be 39.9 ± 0.3%, compared to the natural abundance of 29.8%. With 20–40 mole % of butadiene-1,3 in the hydrogen chloride, calomels containing 83–84% of Hg202 were consistently obtained.The isotopically specific aspects of the reaction in pure hydrogen chloride can be adequately explained by the sequence:[Formula: see text]where M in reaction [3] is a third body or the wall. From the Hg202-abundance data and steady-state considerations, it has been shown that the ratio of partitioning of the absorbed radiation to [1] and [2], respectively, = Φ1/Φ2 = 0.40 ± 0.02. In short, 29% of the primary reaction proceeds by the isotopically specific step [1].The Hg202 content of the calomel product was found to increase markedly when unsaturated hydrocarbons were added to the hydrogen chloride stream. The addends studied included butadiene-1,3, benzene, isoprene, acetylene, propylene, and ethylene in order of decreasing effectiveness. In the presence of the unsaturated addend (U) two additional reactions were postulated to occur:[Formula: see text]From steady-state calculations the effectiveness of the addend can be shown to be determined by the rate ratio, k8/k4.For the maximally enriching mixture of hydrogen chloride and butadiene, the effect of variations in lamp temperature and reaction pressure was studied. At lamp temperatures exceeding approximately 35 °C, reduced enrichments were obtained owing to emission-line broadening. A progressive reduction in enrichment was also observed with substrate pressures greater than 25 mm, owing presumably to Lorentz-broadening of the hyperfine absorption contours of the HgN in the reaction cell.The Hg202 content of the calomel product was determined by resonance radiation absorbiometry. The apparent Hg202 abundances of the mercury recovered from the calomel product were found to depend strongly on the method used for isolating the enriched mercury from the calomel. Evidence was obtained for the occurrence of isotopically degradative exchange reactions during the recovery process. A recovery technique was developed which appeared to eliminate this exchange degradation.

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

1981 ◽  
Vol 55 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
A. Jówko ◽  
S. U. Pavlova ◽  
H. Baj ◽  
B. G. Dzantiev ◽  
M. Foryś
Keyword(s):  
Hydrogen Chloride ◽  
Vacuum Ultraviolet ◽  
Hydrogen Atoms ◽  
Ultraviolet Photolysis

ChemInform Abstract: KINETIC STUDY OF THE REACTION OF HYDROGEN ATOMS WITH HYDROGEN CHLORIDE

1976 ◽  
Vol 7 (48) ◽  
pp. no-no
Author(s):  
P. F. AMBIDGE ◽  
J. N. BRADLEY ◽  
D. A. WHYTOCK
Keyword(s):  
Kinetic Study ◽  
Hydrogen Chloride ◽  
Hydrogen Atoms

PRIMARY PROCESSES IN REACTIONS INITIATED BY PHOTOEXCITED MERCURY ISOTOPES

1958 ◽  
Vol 36 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Harry E. Gunning
Keyword(s):  
Water Vapor ◽  
Hydrogen Chloride ◽  
Methylene Chloride ◽  
Methyl Chloride ◽  
Mercury Vapor ◽  
Enrichment Factors ◽  
Exchange Reactions ◽  
Boron Trichloride ◽  
Mercury Compounds ◽  
Similar Enrichment

A study has been made of the reaction of Hg2026(3P1) atoms, photoexcited in natural mercury vapor; with a number of substrates which form solid mercury compounds in mercury photo-sensitization. Some data are also given for reactions initiated by Hg1986(3P1) atoms. The solid mercury compounds formed were examined for enrichment in the isotope initiating the reaction. Such enrichment would be evidence for the primary formation of the mercury compound.Three HgO-forming substrates were studied: water vapor, nitrous oxide, and oxygen. The Hg2Cl2-forming substrates studied included hydrogen chloride, methyl chloride, methylene chloride, chloroform, carbon tetrachloride, isopropyl chloride, and boron trichloride. One Hg2Br2-forming substrate was examined—isopropyl bromide.Among the HgO-forming substrates only water vapor gave enrichment in Hg202 in the HgO product. The Hg202 content of the oxide was found to vary from 32 to 35%, depending on reaction conditions, compared to a natural abundance of 29.6%. With water vapor – butadiene mixtures, oxides containing as high as 90% Hg202 were obtained. Similar enrichment factors were obtained for Hg1986(3P1) reactions.Hydrogen chloride and the alkyl chlorides yielded calomels containing a maximum of 45% Hg202. Methyl chloride gave similar enrichment factors in Hg198 for the Hg1986(3P1) reaction. The calomel formed in the boron trichloride reaction showed no enrichment.Addends such as butadiene and benzene, when added to hydrogen chloride, increased the Hg202 enrichment from 45% to 60%.For those reactions which yield mercury compounds enriched in the initiating mercury isotope, evidence is presented for a single primary process. Failure to obtain pure isotopes is attributed to exchange reactions with adsorbed natural mercury during recovery of the enriched mercury from the product. It is postulated that the addends react with the mercury product and reduce chemisorption of natural mercury on the product.The significance of these findings in the mechanisms of the reactions studied is discussed.

THE REACTION OF ACTIVE NITROGEN WITH ETHANOL

1965 ◽  
Vol 43 (4) ◽  
pp. 935-939 ◽  
Author(s):  
P. A. Gartaganis
Keyword(s):  
Flow System ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Condensed Discharge ◽  
Preliminary Study ◽  
Fast Flow ◽  
Ethyl Radicals ◽  
Water Hydrogen

The reaction of active nitrogen with ethanol has been investigated in the range 300 to 593 °K using a modified condensed-discharge Wood–Bonhoeffer fast-flow system. The only condensable products found in appreciable amounts were hydrogen cyanide and water. Hydrogen was the main noncondensable product. A very small amount of acetaldehyde was also formed along with traces of ethane, ethylene, methane, acetonitrile, cyanogen, and probably carbon monoxide. The overall activation energy is 3.4 kcal/mole. It is postulated that the mechanism consists of the formation of two fragments NC2H5 and OH, from which the condensable products result as follows:[Formula: see text]A number of products found in trace quantities are produced by concomitant reactions of the hydrogen atoms with methyl radicals, and with ethanol as well as by disproportionation of ethyl radicals to produce ethane and ethylene. A preliminary study of the reaction of active nitrogen with isopropanol indicated that the energy of activation is in line with the energies of activation of methanol and ethanol.

scholarly journals The photosynthesis of hydrogen chloride. II. —“Oxygen free” mixtures

1933 ◽  
Vol 140 (840) ◽  
pp. 112-125 ◽  
Keyword(s):  
Comparative Study ◽  
Transition Region ◽  
Hydrogen Chloride ◽  
The Other ◽  
Pure Hydrogen ◽  
Self Consistent ◽  
Complete Study ◽  
Chlorine Reaction ◽  
Kinetics Of ◽  
Rich Mixtures

The complete study of the photochemical hydrogen-chlorine reaction falls into four sections consequent upon the fact that the presence of oxygen in large or small quantity very materially alters the kinetics of the process. These may be classified as follows:— (1) The kinetics of pure hydrogen-chlorine mixtures. (2) The kinetics of oxygen-rich mixtures. (3) The transition region between (1) and (2). (4) The photosensitized formation of water associated with (2) and (3). A mechanism proposed for any one of the above processes must be consistent with the other three, and a full and comparative study of all four should lead to a self-consistent mechanism by which all the above aspects of the problem can be unified in one explanation.

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