Simplified methods for the calculation of partial pressure using the relative ionization cross-section

Nakao, Fusafumi

doi:10.1016/0042-207x(75)91860-6

Cited by 19 publications

(3 citation statements)

References 18 publications

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“…The plot is simply the ratio of the integrated ion currents ([ethylene/(ethylene + ethanol)] and [propylene/(propylene + 2-propanol)]) without correcting for their respective calibration factors. In fact, the ratios of the relative ionization probabilities for the alcohols to those of their corresponding alkenes are both approximately 1.5. − Therefore, correcting the area ratios will not qualitatively change the plot. As shown in Figure , the yields of ethylene and propylene were strongly coverage dependent, but were not significantly different for the oxidized vs the reduced WO 3 (001) surfaces, demonstrating the insensitivity of the dehydration of alcohols to the surface structure.…”

Section: Resultsmentioning

confidence: 99%

Reactions of Aliphatic Alcohols on WO₃(001) Surfaces

Frederick

2003

J. Phys. Chem. B

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Interactions of ethanol and 2-propanol with oxidized and reduced WO3(001) thin film surfaces, grown epitaxially on a sapphire substrate, were studied with calibrated thermal desorption spectroscopy (CTDS). Coverage-dependent desorption spectra show that alcohol molecules diffuse rapidly on the WO3 thin film surfaces. Ethanol and 2-propanol desorb molecularly between 200 and 450 K with evolution of water. The remaining alkoxy intermediates decompose via β-H elimination, followed by C−O bond scission, to produce ethylene and propylene, respectively. At low coverage, diffusion and competition between reaction rates of dehydroxylation vs associative molecular desorption of alcohol control the alkoxy coverage after the surface hydroxyls are depleted. The remaining alkoxy species undergo β-H elimination and C−O bond scission to produce the alkene. The selectivity toward alkene is controlled by surface reaction kinetics, rather than by surface structure.

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Section: Resultsmentioning

confidence: 99%

Reactions of Aliphatic Alcohols on WO₃(001) Surfaces

Frederick

2003

J. Phys. Chem. B

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“…Williams' group has reported reaction rate constants of proton transfer from [M i + zH] z+ and [M r + zH] z+ to gaseous molecules by means of FT-ICR. 61 Because PA of dipropylamine is almost equivalent to that of Dmpy, 74 the present results of the rate constants with Dmpy can be compared with their results for the reaction with dipropylamine. For [M r + 10H] 10+ , the present values were almost the same as their results.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

“…Detection efficiency for Dmpy with ionization vacuum gauge is assumed to be equal to that for n -heptane. This value is 7.6 compared with that of N 2 . − Conductance of the gas cell and the third vacuum chamber was estimated by considering the evacuation rate of the diffusion pump and diameter of entrance and exit hole of the gas cell. It is confirmed that the pressure in the gas cell is 172 ± 5 times higher than that in the third vacuum chamber.…”

Section: Resultsmentioning

confidence: 99%

Conformations of Disulfide-Intact and -Reduced Lysozyme Ions Probed by Proton-Transfer Reactions at Various Temperatures

et al. 2014

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Proton-transfer reactions of disulfide-intact and -reduced lysozyme ions (7+ through 14+) to 2,6-dimethylpyridine were examined in the gas phase using tandem mass spectrometry with electrospray ionization. By changing temperature of a collision cell from 280 to 460 K, temperature dependence of reaction rate constants and branching fractions was measured. Absolute reaction rate constants for the protein ions of specific charge states were determined from intensities of parent and product ions in the mass spectra. Remarkable change was observed for the rate constants and distribution of product ions. The rate constants for disulfide-intact ions changed more drastically with change of charge states and temperature than those for disulfide-reduced ions. Observed branching fractions for parent and product ions were represented by calculated reaction rate constants with a scheme of sequential process. The reaction rate constants are closely related to conformation changes with change of temperature, which are profoundly influenced by amputation of disulfide bonds.

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