Negative Ion Mass Spectra of Hydrocarbons and Alcohols

Melton, Charles E.; Rudolph, P. S.

doi:10.1063/1.1730641

Cited by 41 publications

(21 citation statements)

References 12 publications

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“…The most pronounced peak appeared at 270.24 amu, which corresponds to the hexadecanol fragment C16D31O -(hexadecanol missing one hydrogen and two deuteriums, M-H-2D). This agrees with the assumption of the alkoxide anions being prone to splitting-off two hydrogen atoms from the carbon next to the oxygen [27]. The recombination of such radical anions on the surface was assumed to cause the formation of double and triple bonds in the alkyl chain [28] or even cross-linking of the alkyl chains, i.e., polymerization of the adsorbed layer [29].…”

Section: Contact Anglesupporting

confidence: 84%

Adsorption of alcohols and fatty acids onto hydrogenated (a-C:H) DLC coatings

Simič

Kalin

Kovač

et al. 2016

Applied Surface Science

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Information about the interactions between lubricants and DLC coatings is scarce, despite there having been many studies over the years. In this investigation we used ToF-SIMS, XPS and contact-angle analyses to examine the adsorption ability and mechanisms with respect to two oiliness additives, i.e., hexadecanol and hexadecanoic acid, on an a-C:H coating. In addition, we analyzed the resistance of the adsorbed films to external influences like solvent cleaning. The results show that both molecules adsorb onto surface oxides and hydroxides present on the initial DLC surface and shield these structures with their hydrocarbon tails. This makes the surfaces less polar, which is manifested in a smaller polar component of the surface energy. We also showed that ultrasonic cleaning in heptane has no significant effect on the quantity of adsorbed molecules or on their chemical state. This not only shows the relatively strong adsorption of these molecules, but provides useful information for future experimental work. Of the two examined molecules, the acid showed a greater adsorption ability than the alcohol, which explains some of the previously reported better tribological properties in the case of the acid with respect to the alcohol. This peer reviewed manuscript has been accepted for publications to the Lubrication Science.

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Section: Contact Anglesupporting

confidence: 84%

Adsorption of alcohols and fatty acids onto hydrogenated (a-C:H) DLC coatings

Simič

Kalin

Kovač

et al. 2016

Applied Surface Science

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“…For estimating the Debye lengths (and functions f and g) of the organic solvents used here, we propose the use of mass spectrometry data to identify likely solvated ions and thereby establish the relation between (measurable) conductivity and ion density (required to predict f and g). Mass spectrometry data are available for numerous organic solvents [31][32][33], and can be classified into two types: for cations and anions. Typically, mass spectrometry data present the abundance of each ion relative to the most abundant ion which is assigned an abundance of 100% [34].…”

Section: Estimating Eo Pumping Performance Of Pure Solventsmentioning

confidence: 99%

High flow rate per power electroosmotic pumping using low ion density solvents

Kim

Posner

Santiago

2008

Sensors and Actuators A: Physical

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“…Gas phase neutralization is prevented, of course, when the electrons reach the wall, even though the positive ions stay much longer in the gas phase. This conclusion is not unexpected, as it is known that saturated hydrocarbons do not readily form negative ions (7).…”

Section: Methodsmentioning

confidence: 59%

The EFFECT OF ELECTRIC FIELDS, AND a RELATED DEPENDENCE ON DOSE RATE, IN THE Γ-Radiolysis OF HYDROCARBON GASES

Woodward¹,

Back²

1963

Can. J. Chem.

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The effect of electric fields on the y-radiolysis of ethane, propane, and the butanes has been investigated briefly a t 800 mm pressure, with dose rates between 2X101° and 400X1010 ev/cc sec. Yields of hydrogen were reduced when a saturation field was applied, except with ethane a t low dose rate, where a slight increase in hydrogen yield was observed. With propane and n-butane, the yield of hydrogen in the presence of a saturation field was independent of dose rate, while with ethane, it decreased with decreasing dose rate. A t the same time, a dose rate dependence was discovered in the simple radiolysis, in the absence of any field, of ethane, propane, and n-butane, a decrease in the yield of hydrogen a t low dose rates being observed. An explanation of these observations is suggested in terms of a competition between neutralization of ions in the gas phase and diffusion of ions to the wall. High dose rates should favor the former process, and low dose rates the latter. At sufficiently high dose rates, all ions should be neutralized in the gas phase. A t sufficiently low dose rates, all ions should diffuse t o the wall before neutralization, and it is suggested that the radiolysis under these conditio~ls should closely reseinble that ill the presence of a saturation field a t higher dose rates.The application of an electric field to a gas during irradiation offers a potential means of -distinguishing between products arising from ions and those forined from neutral species. In practice, the interpretation of the results is very complex, and except for the work of Essex and his collaborators a t Syracuse (I), mostly concerned with a-radiation, the method has not been widely used in radiation chemistry. The present work was undertaken to study the effects oi electric fields on the 7-radiolysis of some simple hydrocarbon gases, using a saturation-current method (2) to measure absolute product yields. In the course of the work, a hitherto unsuspected dependence of hydrogen yield on dose rate was discovered, which appears to be closely related to the action of applied fields on --the radiolysis. EXPERIMENTALThe preparation and purification of hydrocarbon samples for irradiation have been previously described (2, 3). Gases were irradiated in cylindrical vessels of 60-mm 0.d. and about 500-to 600-cc volume. Two experiments with propane were done in a smaller vessel of the same design and length, but with about one-half the diameter and one-quarter the \~olume. The measurement of saturation ion current and of hydrogen yield has been described (2). Electric fields were always applied with the central electrode positive, so that the positive ions were drawn to the other electrode, the graphite-coated wall of the cylindrical vessel. Hydrogen was the only product measured, and the extent of decomposition was always small enough that "internal" scavenging was negligible, and the measured yields were very close to their true initial values (3). Ethylene scavenger was added in some experime~lts, in which case the hyd...

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Negative Ion Mass Spectra of Hydrocarbons and Alcohols

Cited by 41 publications

References 12 publications

Adsorption of alcohols and fatty acids onto hydrogenated (a-C:H) DLC coatings

Adsorption of alcohols and fatty acids onto hydrogenated (a-C:H) DLC coatings

High flow rate per power electroosmotic pumping using low ion density solvents

The EFFECT OF ELECTRIC FIELDS, AND a RELATED DEPENDENCE ON DOSE RATE, IN THE Γ-Radiolysis OF HYDROCARBON GASES

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