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316. The permeability of niobium to hydrogen
188
Classified Abstracts 3 12-3 19
16 312. Adsorption isotherms of nitrogen, benzene and n-hexane and the heats of adsorption of benzene and n-hexane on graphitized carbon blacks. II. Adsorption on graphitized channel blacks. United States. The adsorption isotherms of nitrogen at - 195”, n-hexane at 20”, and the differential heats of adsorption of n-hexane on graphitized channel black have been measured. The shape of the adsorption isotherms and the heats and entropies of adsorption on graphitized carbon blacks are dependent on the dispersion, particle packing, and mosaic character of the surface. When passing from graphitized thermal blacks to graphitized channel blacks, the adsorption isotherms of both nitrogen and n-hexane change from concave to convex in the initial region. Heats of adsorption of helium (measured by other authors) are sensitive indicators of surface inhomogeneity of graphite. (Authors) A. A. Isirikyan and A. V. Kiselev, J. Phys. Chem., 66 (2), Feb. 1962, 205-209.
16 313. Adsorption isotherms of nitrogen, benzene and n-hexane and the heats of adsorption of benzene and n-bexane on graphitized III. The thermodynamic characteristics of carbon blacks. adsorption equilibria. United States. From experimental quantities for graphitized thermal carbon blacks we have obtained and compared the isotherms of the absolute magnitudes of adsorption, and differential heats and entropies of adsorption of n-hexane and benzene on the “ basal plate of graphite,” and also the corresponding standard differential quantities of free and total energy, heat and entropy of adsorption and the extremal values of the differential heats and entropies of adsorption. All these properties are determined solely by the nature of the adsorbateadsorbent system and practically are free from the influence of surface inhomogeneity of the solid. During filling of a monolayer, the heat of adsorption of n-hexane increases by 2, and benzene by 0.3 kcal/mole. The latter value is associated with the considerably weaker adsorbate-adsorbate attractions Accordingly, the adsorption isotherm of benzene of benzene. is at first concave, and of hexane, convex to the pressure axes. A description of the adsorption isotherms of benzene, hexane and nitrogen is discussed in terms of various equations. The BET equation is only a first approximation. Equations taking into account adsorbate-adsorbate attractions yield better agreement. A relationship is established between the constants of these eauations and the constant of the BET equation. The adsorption of benzene and n-hexane at 20” and of nitrogen at -195” on the “ basal plane of graphite ” is predominantly (Authors) localized. A. A. Isirikyan and A. V. Kiselev, J. Phys. Chem., 66 (2), Feb. 1962. 210-215.
16 : 30 314. A search for hydrogen-deuterium exchange on clean germanium surfaces. United States. An attempt has been made to measure hydrogendeuterium exchange on (100) surfaces of a germanium crystal cleaned by outgassing in wcuo and by argon ion bombardment. Tests for the reaction also were made on sputtered films. No activity was found for either type of surface. The lower observable limits of the activity were lOIs molecules cm-’ set-1 for the crystal and 5 x 10” molecules cmmZ set-l for the film. It is concluded that the lack of activity cannot be due to contamination of the surface. A comparison is made between this result and other published results for hydrogen-deuterium (Authors) exchange on germanium. D. Shooter and H. E. Farnsworth, Feb. 1962, 222-224.
J. Phys.
Chem., 66 (2),
16 315. Adsorption and dielectric studies of the alumina-ethyl chloride system at 35”. United States. The adsorption isotherm of ethyl chloride on alumina was determined at 35.0”. The shape of this isotherm resembled that classified by S. Brunauer as Type IV. In conjunction with the isotherm determination, dielectric studies were made on the system. The dielectric constant and loss were measured at frequencies between 100 c and 100 kc for various amounts of adsorbed ethyl chloride. The dielectric loss exhibited an increase until monolayer completion ; then it became relatively constant upon further amounts adsorbed. The dielectric constant increased with increasing amount adsorbed. For any given amount adsorbed, both the dielectric constant and loss decreased with increasing frequency. (Author) R. A. Your& J. Phys. Chem., 66 (2), Feb. 1962, 326-328. 16 316. The permeability of niobium to hydrogen. United States. The permeability (P) of niobium to hydrogen was investigated over a range of temperature between 950 to 1065” and pressure levels of 1.1 and 2.0 atm. The resulting permeability was found to obey the relationship cm3Hz(0”, 1 atm) hrm’ p = 2.01 x 10+5208+'40~RT
cmzmm_;Gci,,
D. W. Rudd, D. W. Vose and S. Johnson, 66 (2), Feb. 1962, 351-353.
(Authors) J. Phys. Chem.,
16 317. The chemisorption of nitric oxide by alumina gel at 0’. A. Solbakken and L. H. Reyerson, J. Phys. Chem., 66 (2), Feb. 1962, 365-366. 16 : 37 318. Translational energy accommodation in the nickel-chlorine surface reaction. United States. A method of measuring the transfer of translational energy in gas-surface collisions is described. Mass spectrometric measurements were made of a collimated beam of unreacted chlorine reflected from the nickel surface at surface temperatures between 1100 and 1600°K. By a simple modification- of the mass spectrometer ion source it was possible to measure the flux and density of this beam. The latter equals the flux divided by the average velocity of the beam molecules, and the ratio of the two quantities gives the average beam velocity. The accommodation coefficient of the beam gas on the reflecting surface can be computed from this velocity together with the temperature of the beam before reflection and the surface temperature. Experiments were carried out in a stainless steel vacuum system consisting of three separately pumped chambers connected in series by collimating slits, 0.005 x 0.5 in. Chlorine from an effusion source in the first chamber passes as a collimated beam into the second chamber where it strikes a nickel target mounted with its long axis 45” to the beam A beam of evaporated reaction products and reflected direction. chlorine collimated at right angles to the incident beam passes into the third chamber containing the ion source of a pulsed (Author) beam time-of-flight mass spectrometer. J. D. McKinley,
J. Phys. Chem., 66 (3), March 1962, 554-556. 16
319. The mechanism of chemisorption : carbon monoxide and carbon dioxide on nickel. United States. Magnetization-volume isotherms on nickelsilica have been obtained for carbon monoxide and carbon dioxide by the low frequency a.c. permeameter method. The mode of bonding of carbon monoxide is dependent on nickel particle size and on surface coverage, in qualitative agreement
Classified Abstracts 3 12-3 19
16 312. Adsorption isotherms of nitrogen, benzene and n-hexane and the heats of adsorption of benzene and n-hexane on graphitized carbon blacks. II. Adsorption on graphitized channel blacks. United States. The adsorption isotherms of nitrogen at - 195”, n-hexane at 20”, and the differential heats of adsorption of n-hexane on graphitized channel black have been measured. The shape of the adsorption isotherms and the heats and entropies of adsorption on graphitized carbon blacks are dependent on the dispersion, particle packing, and mosaic character of the surface. When passing from graphitized thermal blacks to graphitized channel blacks, the adsorption isotherms of both nitrogen and n-hexane change from concave to convex in the initial region. Heats of adsorption of helium (measured by other authors) are sensitive indicators of surface inhomogeneity of graphite. (Authors) A. A. Isirikyan and A. V. Kiselev, J. Phys. Chem., 66 (2), Feb. 1962, 205-209.
16 313. Adsorption isotherms of nitrogen, benzene and n-hexane and the heats of adsorption of benzene and n-bexane on graphitized III. The thermodynamic characteristics of carbon blacks. adsorption equilibria. United States. From experimental quantities for graphitized thermal carbon blacks we have obtained and compared the isotherms of the absolute magnitudes of adsorption, and differential heats and entropies of adsorption of n-hexane and benzene on the “ basal plate of graphite,” and also the corresponding standard differential quantities of free and total energy, heat and entropy of adsorption and the extremal values of the differential heats and entropies of adsorption. All these properties are determined solely by the nature of the adsorbateadsorbent system and practically are free from the influence of surface inhomogeneity of the solid. During filling of a monolayer, the heat of adsorption of n-hexane increases by 2, and benzene by 0.3 kcal/mole. The latter value is associated with the considerably weaker adsorbate-adsorbate attractions Accordingly, the adsorption isotherm of benzene of benzene. is at first concave, and of hexane, convex to the pressure axes. A description of the adsorption isotherms of benzene, hexane and nitrogen is discussed in terms of various equations. The BET equation is only a first approximation. Equations taking into account adsorbate-adsorbate attractions yield better agreement. A relationship is established between the constants of these eauations and the constant of the BET equation. The adsorption of benzene and n-hexane at 20” and of nitrogen at -195” on the “ basal plane of graphite ” is predominantly (Authors) localized. A. A. Isirikyan and A. V. Kiselev, J. Phys. Chem., 66 (2), Feb. 1962. 210-215.
16 : 30 314. A search for hydrogen-deuterium exchange on clean germanium surfaces. United States. An attempt has been made to measure hydrogendeuterium exchange on (100) surfaces of a germanium crystal cleaned by outgassing in wcuo and by argon ion bombardment. Tests for the reaction also were made on sputtered films. No activity was found for either type of surface. The lower observable limits of the activity were lOIs molecules cm-’ set-1 for the crystal and 5 x 10” molecules cmmZ set-l for the film. It is concluded that the lack of activity cannot be due to contamination of the surface. A comparison is made between this result and other published results for hydrogen-deuterium (Authors) exchange on germanium. D. Shooter and H. E. Farnsworth, Feb. 1962, 222-224.
J. Phys.
Chem., 66 (2),
16 315. Adsorption and dielectric studies of the alumina-ethyl chloride system at 35”. United States. The adsorption isotherm of ethyl chloride on alumina was determined at 35.0”. The shape of this isotherm resembled that classified by S. Brunauer as Type IV. In conjunction with the isotherm determination, dielectric studies were made on the system. The dielectric constant and loss were measured at frequencies between 100 c and 100 kc for various amounts of adsorbed ethyl chloride. The dielectric loss exhibited an increase until monolayer completion ; then it became relatively constant upon further amounts adsorbed. The dielectric constant increased with increasing amount adsorbed. For any given amount adsorbed, both the dielectric constant and loss decreased with increasing frequency. (Author) R. A. Your& J. Phys. Chem., 66 (2), Feb. 1962, 326-328. 16 316. The permeability of niobium to hydrogen. United States. The permeability (P) of niobium to hydrogen was investigated over a range of temperature between 950 to 1065” and pressure levels of 1.1 and 2.0 atm. The resulting permeability was found to obey the relationship cm3Hz(0”, 1 atm) hrm’ p = 2.01 x 10+5208+'40~RT
cmzmm_;Gci,,
D. W. Rudd, D. W. Vose and S. Johnson, 66 (2), Feb. 1962, 351-353.
(Authors) J. Phys. Chem.,
16 317. The chemisorption of nitric oxide by alumina gel at 0’. A. Solbakken and L. H. Reyerson, J. Phys. Chem., 66 (2), Feb. 1962, 365-366. 16 : 37 318. Translational energy accommodation in the nickel-chlorine surface reaction. United States. A method of measuring the transfer of translational energy in gas-surface collisions is described. Mass spectrometric measurements were made of a collimated beam of unreacted chlorine reflected from the nickel surface at surface temperatures between 1100 and 1600°K. By a simple modification- of the mass spectrometer ion source it was possible to measure the flux and density of this beam. The latter equals the flux divided by the average velocity of the beam molecules, and the ratio of the two quantities gives the average beam velocity. The accommodation coefficient of the beam gas on the reflecting surface can be computed from this velocity together with the temperature of the beam before reflection and the surface temperature. Experiments were carried out in a stainless steel vacuum system consisting of three separately pumped chambers connected in series by collimating slits, 0.005 x 0.5 in. Chlorine from an effusion source in the first chamber passes as a collimated beam into the second chamber where it strikes a nickel target mounted with its long axis 45” to the beam A beam of evaporated reaction products and reflected direction. chlorine collimated at right angles to the incident beam passes into the third chamber containing the ion source of a pulsed (Author) beam time-of-flight mass spectrometer. J. D. McKinley,
J. Phys. Chem., 66 (3), March 1962, 554-556. 16
319. The mechanism of chemisorption : carbon monoxide and carbon dioxide on nickel. United States. Magnetization-volume isotherms on nickelsilica have been obtained for carbon monoxide and carbon dioxide by the low frequency a.c. permeameter method. The mode of bonding of carbon monoxide is dependent on nickel particle size and on surface coverage, in qualitative agreement