The Vapor Phase Radiolysis of Isopropanol and Water–Isopropanol Mixtures. II. Nitrous Oxide as Electron Scavenger

1971 ◽  
Vol 49 (17) ◽  
pp. 2909-2912 ◽  
Author(s):  
M. G. Bailey ◽  
R. S. Dixon
Keyword(s):  
Nitrous Oxide ◽  
Vapor Phase ◽  
Electron Attachment ◽  
Hydrogen Yield ◽  
Reactive Intermediate ◽  
Secondary Species ◽  
Electron Yield ◽  
Electron Scavenger ◽  
Vapor Mixtures ◽  
Reaction With Water

Nitrous oxide reduces the hydrogen yield from water–isopropanol vapor mixtures by complete scavenging of electrons. Nitrogen is produced over the whole concentration range but the yield at higher isopropanol concentrations is much greater than the electron yield. The results indicate a competition between water and isopropanol for a secondary species resulting from electron attachment to N2O. Reaction of this species with isoprooanol leads to further N2 whereas reaction with water does not. The reactive intermediate is most probably N2O− or N2O2−.

THE RADIOLYSIS OF ETHANOL: II. BINARY VAPOR MIXTURES

1961 ◽  
Vol 39 (9) ◽  
pp. 1843-1847
Author(s):  
J. M. Ramaradhya ◽  
G. R. Freeman
Keyword(s):  
Experimental Data ◽  
Kinetic Parameters ◽  
Vapor Phase ◽  
Reaction Mechanisms ◽  
Marked Decrease ◽  
Hydrogen Yield ◽  
Hydrogen Atoms ◽  
Energy Excitation ◽  
Straight Line ◽  
Vapor Mixtures

Benzene and cyclohexene cause a marked decrease in the hydrogen yield from the vapor phase radiolysis of ethanol.The experimental data were tested against the two reaction mechanisms that gave straight-line plots for the corresponding cyclohexane–protector systems. Both of these mechanisms also gave straight-line plots for the ethanol–protector systems.One mechanism involved scavenging of hydrogen atoms. The values of the kinetic parameters derived from this mechanism are quite similar in the cyclohexane and ethanol systems.The second mechanism involved the transfer of energy (excitation or ionization) from ethanol to the protector. The values of the kinetic parameters derived from this mechanism showed some differences between the ethanol and cyclohexane systems.One possible reason for the lack of resolution between the two reaction mechanisms might be that they both occur to comparable extents. Two mechanisms appear to occur to comparable extents in the liquid cyclohexane system.

Effects of electron scavengers in the radiolysis of water vapor

1968 ◽  
Vol 46 (8) ◽  
pp. 1181-1186 ◽  
Author(s):  
R. S. Dixon ◽  
M. G. Bailey
Keyword(s):  
Nitrous Oxide ◽  
Water Vapor ◽  
Cross Sections ◽  
Electron Attachment ◽  
Hydrogen Yield ◽  
X Rays ◽  
Nitrogen Yield ◽  
Wide Range ◽  
Higher Doses ◽  
Limiting Values

Water vapor irradiated with X-rays in the presence of nitrous oxide gives mainly nitrogen and oxygen together with small amounts of hydrogen and, possibly, hydrogen peroxide. The yield of nitrogen, G(N2) = 3.0 ± 0.3, is constant over a wide range of conditions and G(O2) = 1.6 ± 0.3 after an induction period. The hydrogen yield is constant at low doses with G(H2) = 0.45 ± 0.1, but reaches a steady state at higher doses. The nitrogen yield is equated with the yield of scavengeable electrons in water vapor, the value g(e) = 3.0 ± 0.3 being in reasonable agreement with the theoretical value based on W(H2O) = 30 eV. Addition of other electron scavengers to water vapor containing nitrous oxide suppresses the nitrogen yield by competing efficiently for electrons. On the basis of their efficiency in suppressing the nitrogen yield, limiting values for the relative rates of reaction of N2O, SF6, CCl4, and HCl with electrons in water vapor are obtained and comparisons are made with their known electron attachment cross sections in the gas phase.

The High Dose Rate Radiolysis of H2S: Sulfur as an Electron Scavenger

1973 ◽  
Vol 51 (8) ◽  
pp. 1228-1234 ◽  
Author(s):  
A. W. Boyd ◽  
C. Willis ◽  
O. A. Miller
Keyword(s):  
Hydrogen Sulfide ◽  
Dose Rate ◽  
Electron Attachment ◽  
High Dose Rate ◽  
Gaseous Hydrogen ◽  
High Dose ◽  
Hydrogen Yield ◽  
Attachment Rate ◽  
Electron Scavenger

The radiolysis of gaseous hydrogen sulfide has been studied in the presence of added sulfur at 200–250 °C. At 2 × 1027 eV g−1 s−1 sulfur reduces the hydrogen yield from G(H2) = 12.0 ± 0.3 to G(H2) = 7.3 ± 0.3. This reduction in yield appears to be due to electron attachment by the sulfur thereby suppressing formation of hydrogen from dissociative neutralization. Assuming the sulfur is S8 we estimate the attachment rate of electrons to sulfur to be about 1 × 1014 M−1 s−1.At 25 °C the reduction in the H2 yield at 2 × 1027 eV g−1 s−1 with increasing dose appears to be due to polysulfanes rather than radiolytic sulfur.Over the range of 1026 – 1028 eV g−1 s−1 the H2 yield increases from G(H2) = 11 to G(H2) = 13. Mechanisms to account for this increase are discussed.

γ-Radiolysis of cyclohexane with electron scavengers. VI. N2O and SF6 as electron scavengers in the vapor phase

1968 ◽  
Vol 46 (22) ◽  
pp. 3511-3516 ◽  
Author(s):  
N. H. Sagert ◽  
R. W. Robinson ◽  
A. S. Blair
Keyword(s):  
Carbon Dioxide ◽  
Vapor Phase ◽  
General Mechanism ◽  
Hydrogen Yield ◽  
Neutral Species ◽  
First Order ◽  
Nitrogen Yield

The γ-radiolysis of cyclohexane has been examined in the vapor phase using N2O and SF6 as electron scavengers. Both N2O and SF6 reduce the hydrogen yield from 4.6 to 3.0 G units, indicating that 3.0 G units of hydrogen have neutral species as precursors, while 1.6 G units have electrons as precursors.Radiolysis of cyclohexane vapor with more than 2% N2O produces 10.4 G units of cyclohexene and 11.5 of nitrogen. Carbon dioxide reduces both these yields; the extrapolated value of G(N2) is equal to G(electrons) at infinite CO2 concentration. Thus O− is likely a precursor of that part of the nitrogen yield in excess of G(electrons), and of the cyclohexene yield associated with this nitrogen yield.The first order molecular detachment of hydrogen is unaffected by electron scavengers, showing that most of this first order yield has neutral precursors. The implications for Dyne's general mechanism of hydrocarbon radiolysis are discussed.

scholarly journals Radiolysis of methylcyclohexane. IV. Effects of carbon tetrachloride and nitrous oxide in the vapor phase

1967 ◽  
Vol 45 (14) ◽  
pp. 1661-1668 ◽  
Author(s):  
W. J. Holtslander ◽  
G. R. Freeman
Keyword(s):  
Nitrous Oxide ◽  
Carbon Tetrachloride ◽  
Vapor Phase ◽  
Electron Affinity ◽  
Exothermic Reaction ◽  
Product Formation ◽  
Chain Termination ◽  
Chain Reaction ◽  
Positive Ions ◽  
Radiation Induced

There is a radiation-induced chain reaction in methylcyclohexane (MCH) – CCl4 mixtures in the vapor phase at 110° and 380 Torr. The chain-propagation products are chloroform and methylcyclohexylchloride (Gmax ≈ 40) and the chain-termination products are mainly methylcyclohexene (MC), bimethylcyclohexyl (C14), and hexachloroethane, depending on the composition of the mixture. At CCl4 concentrations < 1 mole%, HCl is formed mainly by reaction of Cl− with positive ions, e.g. Cl− + C7H14+ → HCl + C7H13. The value of the ratio G(MC)/G(C14) is 8 ± 1 in pure MCH and in the mixtures up to 44 mole% CCl4.There is a radiation-induced chain reaction in MCH–N2O mixtures in the vapor phase. At 110° and 380 Torr, G(N2) = 22, G(MC) = 16, and G(C14) = 1.6, independent of N2O concentration between 2 and 10 mole%. The G-values are independent of MCH pressure between 50 and 520 Torr. Product formation is inhibited by the addition of SF6 or DI. The half-life of the ion N2O− with respect to decomposition to N2 + O− is 10−4–10−3 s under these conditions. It is suggested that the mechanism contains the reactions [Formula: see text] [Formula: see text]Reaction [24] is slightly exothermic. Reaction [25] is exothermic if the electron affinity of N2O is greater than that of C7H13.

Another look at the electron attachment to nitrous oxide

2001 ◽  
Vol 114 (18) ◽  
pp. 7911-7917 ◽  
Author(s):  
Eugene S. Kryachko ◽  
Chris Vinckier ◽  
Minh Tho Nguyen
Keyword(s):  
Nitrous Oxide ◽  
Electron Attachment
Sign in / Sign up

Export Citation Format

Share Document