THE RADIOLYSIS OF CYCLOHEXANE: IV. BINARY MIXTURES IN THE VAPOR PHASE

1961 ◽  
Vol 39 (9) ◽  
pp. 1769-1775 ◽  
Author(s):  
J. M. Ramaradhya ◽  
G. R. Freeman
Keyword(s):  
Experimental Data ◽  
Reaction Mechanisms ◽  
Excited Molecule ◽  
Hydrogen Yield ◽  
Hydrogen Atoms ◽  
Energy Excitation ◽  
Gaseous Mixtures ◽  
Straight Line ◽  
Positive Ion ◽  
Mechanisms Of Reactions

The variation of the hydrogen yield with the composition of binary gaseous mixtures containing cyclohexane and benzene, cyclohexene, or propylene is qualitatively similar to that in the liquid phase.The quantitative experimental data were tested against several possible reaction mechanisms and two mechanisms gave straight-line plots.One mechanism involved scavenging of hydrogen atoms. The values of the kinetic parameters derived from this mechanism might not be unreasonable in the mixtures of cyclohexane with cyclohexene or propylene. The values for benzene, however, seem less likely.The second mechanism involved the transfer of energy (excitation or ionization) from cyclohexane to the second substance. The values of the ratio of the rate constants, k7/k6, of the reactions[Formula: see text]is about 103 times greater in the gas than in the liquid phase. Consideration of possible detailed mechanisms of reactions [6] and [7] indicates that this difference is reasonable if C6H12** is a positive ion rather than an excited molecule.

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.

The X-radiolysis of water vapor containing methanol. Effects of some electron and hydrogen atom scavengers

1968 ◽  
Vol 46 (12) ◽  
pp. 1957-1964 ◽  
Author(s):  
R. S. Dixon ◽  
M. G. Bailey
Keyword(s):  
Nitrous Oxide ◽  
Water Vapor ◽  
Carbon Tetrachloride ◽  
Hydrogen Atom ◽  
Sulfur Hexafluoride ◽  
Hydrogen Yield ◽  
Hydrogen Atoms ◽  
A Value ◽  
Ion Recombination ◽  
Positive Ion

The X-radiolysis of water vapor containing methanol at 125 °C and 1 atm pressure has been studied alone and in the presence of some electron and hydrogen atom scavengers. In water vapor containing methanol only, a plateau value G(H2) = 7.9 ± 0.3 is obtained at all methanol concentrations above 0.5 mole %. Addition of propylene drastically reduces this yield due to efficient scavenging of hydrogen atoms, and values for the total number of H atoms from all precursors g(H)t = 7,5 ± 0.2 and [Formula: see text] are deduced from the competition. An unscavengeable hydrogen yield g(H2) ~ 0.5 is also indicated in mixtures containing propylene. Nitrous oxide and sulfur hexafluoride are found to scavenge electrons efficiently in water vapor containing methanol and the number of hydrogen atoms arising from electron–positive ion recombination is estimated to have a value G = 2.2 ± 0.6. The number of hydrogen atoms arising from processes not involving electrons is g(H) = 5.2 ± 0.3. Carbon tetrachloride reacts efficiently with both electrons and hydrogen atoms, with k(H + CH3OH)/k(H + CCl4) = 0.085. Values of g(H) = 4.9 ± 0.5 and g(H2) = 0.8 ± 0.2 are deduced from mixtures containing carbon tetrachloride.

RADIATION CHEMISTRY OF CYCLOHEXANE: VI. DILUTE SOLUTIONS OF CARBON TETRACHLORIDE AND CHLOROFORM IN CYCLOHEXANE

1964 ◽  
Vol 42 (3) ◽  
pp. 669-681 ◽  
Author(s):  
J. A. Stone ◽  
P. J. Dyne
Keyword(s):  
Carbon Tetrachloride ◽  
Chemical Reaction ◽  
Physical Process ◽  
Radical Scavenging ◽  
Radiation Chemistry ◽  
Hydrogen Yield ◽  
Halogenated Compounds ◽  
Dilute Solutions ◽  
Hydrogen Atoms

A study of the effect of the addition of small amounts (<3.5%) of the halogenated compounds CCl4, CHCl3, and CDCl3 on the radiolysis of cyclohexane has shown that processes other than radical scavenging occur. At the lowest concentrations of solute that it was practical to employ (0.004 M) cyclohexyl radicals were scavenged without a corresponding reduction in the hydrogen yield. At higher solute concentrations G(H2) was reduced by a physical process which did not involve the scavenging of thermal hydrogen atoms but did lead to chemical reaction involving the solute.

Kinetics of Hydrogen Absorption, Desorption And Permeation of Metals

CORROSION ◽  
1958 ◽  
Vol 14 (12) ◽  
pp. 34-38 ◽  
Author(s):  
T. G. OWE BERG
Keyword(s):  
Experimental Data ◽  
Reaction Mechanisms ◽  
Hydrogen Absorption ◽  
Hydrogen Gas ◽  
Acid Solutions ◽  
Dilute Acid ◽  
Energy Diffusion ◽  
Dissolved Hydrogen ◽  
Kinetics Of ◽  
Absorption Of Hydrogen

Abstract The reaction mechanisms for the absorption of hydrogen by metals from moist hydrogen gas and dilute acid solutions, for the desorption from metals of dissolved hydrogen in the presence of water and for hydrogen solubility and permeation under those conditions are discussed. Their kinetics are also given. Formulae are derived for rates and equilibria. These are compared with experimental data. The migration of H atoms in the metal is concluded to be associated with zero or nearly zero activation energy. Diffusion is rapid enough to maintain almost uniform distribution of H atoms in the metal during absorption and desorption under ordinary conditions. 3.8.4

An Electronic Model of a Neural Correlate to Experience Obtained When the Stimulus Object is a Straight Line or a Circle

1967 ◽  
Vol 25 (1) ◽  
pp. 189-202 ◽  
Author(s):  
Kristian Holt-Hansen
Keyword(s):  
Experimental Data ◽  
Brain Function ◽  
Stimulus Object ◽  
The Other ◽  
Neural Correlate ◽  
Close Analogy ◽  
Straight Line ◽  
Electronic Model ◽  
Close Relationship ◽  
The Brain

An attempt was made to present an electronic model of the neural correlate to the experiences of straightness and circularity on the basis of experimental data. Two sets of experiments were described. In one Ss had numerous kinds of experience when the stimulus object was a straight line or a circle. These experiments demonstrated a close relationship between a straight line and a circle in experience. The other set of experiments consisted of adjusting the electric voltages fed into a cathode ray oscilloscope so that the displays on the screen corresponded closely to some of the experiences reported by subjects in the first set of experiments. A plausible working hypothesis was put forward on the basis that the electronic functions underlying the working of a cathode ray oscilloscope suggest a close analogy with the brain function underlying the experiences obtained when the stimulus object is a straight line or a circle.

Influences of Trace Water in Hydrogen and Argon on the Tribological Properties of Pure Iron

2012 ◽  
Author(s):  
Kanao Fukuda ◽  
Masaaki Hashimoto ◽  
Joichi Sugimura
Keyword(s):  
Experimental Data ◽  
Tribological Properties ◽  
Pure Iron ◽  
Synergy Effect ◽  
Hydrogen Atoms ◽  
Wear Rates ◽  
Hydrogen Environment ◽  
Trace Water ◽  
Nascent Surface

Tribological properties of pure iron were studied in argon environments containing trace water which is controlled at the value between 1 and 10,000 ppb and virtually no oxygen. The experimental data were compared with those obtained in our previous study with the same conditions of experiment but in hydrogen. The influences of trace water were recognized in both gases and confirmed not peculiar to a hydrogen environment. The coefficients of friction and specific wear rates were different to some extent between argon and hydrogen environments. The differences were supposed to be attributed to the influences of hydrogen atoms which chemisorbed on pure iron atoms appeared on the nascent surface made by sliding. Whether hydrogen and water have synergy effect on influencing tribological properties was not clarified in this study.

Anisotropically Nanostructured Silicon: A First-Principle Approach.

2004 ◽  
Vol 832 ◽  
Author(s):  
Yuri Bonder ◽  
Chumin Wang
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
First Principle ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Nanostructured Silicon ◽  
Plane Anisotropy ◽  
The Density Functional Theory ◽  
The Difference ◽  
Good Agreement

ABSTRACTOptical properties of birefringent porous-silicon layers are studied within the density functional theory. Starting from a (110)-oriented supercell of 32 silicon atoms, columns of atoms in directions [100] and [010] are removed and the dangling bonds are saturated with hydrogen atoms. The results show an in-plane anisotropy in the dielectric function and in the refractive index (n). The difference Δn defined as n[110] -n[001] is compared with experimental data and a good agreement is observed. Also, the possibility in determining the morphology of pores by using polarized lights is analyzed.

scholarly journals A Barrierless Pathway Accessing the C9H9 and C9H8 Potential Energy Surfaces via the Elementary Reaction of Benzene with 1-Propynyl

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aaron M. Thomas ◽  
Srinivas Doddipatla ◽  
Ralf I. Kaiser ◽  
Galiya R. Galimova ◽  
Alexander M. Mebel
Keyword(s):  
Experimental Data ◽  
Electronic Structure ◽  
Reaction Mechanisms ◽  
Potential Energy Surfaces ◽  
Molecular Beams ◽  
Underlying Mechanism ◽  
Extreme Conditions ◽  
Stable Isomer ◽  
Polycyclic Aromatic ◽  
Energy Surfaces

AbstractThe crossed molecular beams reactions of the 1-propynyl radical (CH3CC; X2A1) with benzene (C6H6; X1A1g) and D6-benzene (C6D6; X1A1g) were conducted to explore the formation of C9H8 isomers under single-collision conditions. The underlying reaction mechanisms were unravelled through the combination of the experimental data with electronic structure and statistical RRKM calculations. These data suggest the formation of 1-phenyl-1-propyne (C6H5CCCH3) via the barrierless addition of 1-propynyl to benzene forming a low-lying doublet C9H9 intermediate that dissociates by hydrogen atom emission via a tight transition state. In accordance with our experiments, RRKM calculations predict that the thermodynamically most stable isomer – the polycyclic aromatic hydrocarbon (PAH) indene – is not formed via this reaction. With all barriers lying below the energy of the reactants, this reaction is viable in the cold interstellar medium where several methyl-substituted molecules have been detected. Its underlying mechanism therefore advances our understanding of how methyl-substituted hydrocarbons can be formed under extreme conditions such as those found in the molecular cloud TMC-1. Implications for the chemistry of the 1-propynyl radical in astrophysical environments are also discussed.

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