- Email: [email protected]
488. Infrared and volumetric data on the adsorption of ammonia, water, and other gases on activated iron (III) oxide
200
Classified Abstracts
479-488
12 : 22 Evaluation
of
calibration
methods
for
ionization
gauges.
See
Abstr. No. 509.
studies
on metals.
: Water
XI
16 on n-type
ger-
manium powders. U.S.A. Water adsorption
13.
Vacuum Applications 13 : 54
479. Vacuum refrigeration of vegetable products. France. The mechanisms of vacuum cooling
are analysed. The relationship between water evaporation and temperature reduction is given and the rapidity of the process is stressed. Various types of vacuum chamber, and two processes for the removal of air from these chambers are described. The behaviour of vacuum-cooled vegetable products is examined, and particular attention is given to the possible means of preventing weight losses due to evaporation. The technical and economic advantages and limitations of the method are discussed. (in French) (Author, modified)
R. Thevenot,
483. Adsorption
Le W/e,
17 (lo]),
Sept./Ott.
measurements were carried out at 25” for three n-type germanium powders previously exposed to the atmosphere. These, as well as argon adsorption measurements for surface areas, were conducted on samples evacuated and temperature activated at 25, 100, 200, 300, 400, and 500”. The amount of water irreversibly adsorbed were also determined. The results revealed that the extent and energetics of chemisorbed water decreased with decreasing resistivity. In addition, the stability of the thin oxide film formed on the germanium powders during grinding of the single crystals to prepare the powders and during the storage, decreased in the same order. Evidently, water adsorbs donor-fashion on surface hydroxyl groups. Therefore, samples of low resistivity and high electron concentration chemisorb little or no water. (Authors) G. Srinivasan, ef al., J. Phys. Chem., 66, Oct. 1962, 1819-1822.
1962, 457-464. 16
15.
484. Heats of immersion.
VII in hexane-variation
Fluid Dynamics 15
480. Investigation of a first-order slip-flow continuum. the thermal force. U.S.A. Comparison of an equation for the thermal
Analysis:
force on aerosol particles, derived by a first-order slip-flow continuum analysis, with experimental thermal force data reveals that the analysis breaks down for Knudsen numbers greater than 0.25 Evaluation of first-order slip-flow coefficients from thermal force data is discussed. Numerical values of the slip-flow coefficients are reported for several gas-surface systems. (Author) J. R. Brock, J. Phys. Chem., 66, Oct. 1962, 1763-1767.
16.
Gases and Solids
: The immersion of silica, alumina,
and titania with particle size and outgassing temperature. U.S.A. The heats of immersion of the three substrate materials
in hexane have been measured as a function of particle sizeand outgassing temperature. The results are interpreted in terms of van der Waals and ion-induced dipole interactions. (Authors) W. H. Wade and N. Hackerman, 1823-l 826.
J. Phys.
Chm.,
66, Oct. 1962,
16 485. Adsorption
of argon on graphitized carbon black. Surface area and heats and entropies of adsorption. U.S.A. Adsorption isotherms of argon on the highly graphitized
carbon black P33 (2700”) between 90 and 137°K are presented. Estimates of the surface area of the adsorbent and heats and entropies of adsorption computed from the data are discussed. The present results are compared with quantities obtained through the virial coefficient treatment of physical adsorption. (Authors)
16 481. Multilayers of argon and nitrogen on hexagonal boron nitride. U.S.A. Multilayer adsorption isotherms of argon on boron nitride have been determined at 66.0, 68.9, and 75.9”K. In addition, multilayer isotherms of nitrogen on boron nitride have been determined at 63.30 and 65.79”K. Isosteric heats of adsorption have been obtained and are compared with the isosteric heats of adsorption of argon on graphite (P-33). The interaction energies of adsorption are determined for argon on P-33 and boron nitride by means of the Singleton-Halsey isotherm equation and are compared with the interaction energies calculated by dispersion energy summations. The calculated and observed interaction energies for argon-boron nitride are in good agreement. The observed interaction energy of argon with graphite is larger than that calculated. This discrepancy (Author) is discussed in terms of various interaction theories.
16 486. An infrared study of a silica-alumina surface. U.S.A. In highly dehydrated samples of silica-alumina a single band is observed in the OH stretching region. The results imply that a single surface hydroxyl group type attached to silicon atoms predominates in these samples. The interaction of water with the surface of highly dehydrated silica-alumina is investigated, and it is established that fixedly adsorbed water is held on acidic sites far enough removed from surface hydroxyl groups that hydrogen-bonding to these groups does not occur. The bands in the silica-alumina spectrum from 4000-1000 cm-’ are tentatively assigned, including one which is thought to be (Author) due to the Al0 linkage in an acidic surface group.
R. A. Pierotti,
M. R. Basila, J. Phys.
J. Phys.
Chem.,
66, Oct. 1962, 1810-1815.
J. R. Sams, et al., J. Phys.
Chem.,
Gem.,
66, Nov.
66, Nov.
1962, 2154-2158.
1962, 2223-2228.
chloride
16 films.
66, Nov.
1962.
16 on low energy solids. I : Adsorption of argon and nitrogen on polytetrafluoro-
482. Physical adsorption
carbon tetrafluoride, ethylene. U.S.A. Carbon tetrafluoride,
argon and nitrogen, at temperatures near their respective boiling points, are adsorbed on polytetrafluoroethylene with isosteric heats of adsorption only slightly greater than the corresponding latent heats of condensation. In all cases, the adsorbates are mobile, nitrogen retaining some “ super mobility “. Film pressures at a coverage representing one statistical monolayer are 9.5 to 10 ergs/cml. Additional monolayers are adsorbed with abnormally low isosteric (Author) heats indicating multilayer films of low density. D. Graham,
J. Ph.17.r. Chem.,
66, Oct. 1962, 181.5-181X.
487. Adsorption (U.S.A.)
of water
vapor
P. G. Hall and F. C. Tompkins,
on potassium J. Phys.
Chern.,
2260-2262. 16 488. Infrared and volumetric data on the adsorption of ammonia, water, and other gases on activated iron (III) oxide. U.S.A. Infrared spectra in the 2 to 13~ range have been
obtained of NH,, H,O, H,S, EtOH, and Et,0 chemisorbed on N,, O,, H,, CO, SO,, Cl,, C,H, and C,H( do not a-FelO,. chemisorb at 25” on a-Fe,O,. H,O chemisorbs by dissociating to form a OH- ion and a proton which reacts with a surface 0-* ion to produce another OH- ion. NH, upon chemisorption
Classified Abstracts
479-488
12 : 22 Evaluation
of
calibration
methods
for
ionization
gauges.
See
Abstr. No. 509.
studies
on metals.
: Water
XI
16 on n-type
ger-
manium powders. U.S.A. Water adsorption
13.
Vacuum Applications 13 : 54
479. Vacuum refrigeration of vegetable products. France. The mechanisms of vacuum cooling
are analysed. The relationship between water evaporation and temperature reduction is given and the rapidity of the process is stressed. Various types of vacuum chamber, and two processes for the removal of air from these chambers are described. The behaviour of vacuum-cooled vegetable products is examined, and particular attention is given to the possible means of preventing weight losses due to evaporation. The technical and economic advantages and limitations of the method are discussed. (in French) (Author, modified)
R. Thevenot,
483. Adsorption
Le W/e,
17 (lo]),
Sept./Ott.
measurements were carried out at 25” for three n-type germanium powders previously exposed to the atmosphere. These, as well as argon adsorption measurements for surface areas, were conducted on samples evacuated and temperature activated at 25, 100, 200, 300, 400, and 500”. The amount of water irreversibly adsorbed were also determined. The results revealed that the extent and energetics of chemisorbed water decreased with decreasing resistivity. In addition, the stability of the thin oxide film formed on the germanium powders during grinding of the single crystals to prepare the powders and during the storage, decreased in the same order. Evidently, water adsorbs donor-fashion on surface hydroxyl groups. Therefore, samples of low resistivity and high electron concentration chemisorb little or no water. (Authors) G. Srinivasan, ef al., J. Phys. Chem., 66, Oct. 1962, 1819-1822.
1962, 457-464. 16
15.
484. Heats of immersion.
VII in hexane-variation
Fluid Dynamics 15
480. Investigation of a first-order slip-flow continuum. the thermal force. U.S.A. Comparison of an equation for the thermal
Analysis:
force on aerosol particles, derived by a first-order slip-flow continuum analysis, with experimental thermal force data reveals that the analysis breaks down for Knudsen numbers greater than 0.25 Evaluation of first-order slip-flow coefficients from thermal force data is discussed. Numerical values of the slip-flow coefficients are reported for several gas-surface systems. (Author) J. R. Brock, J. Phys. Chem., 66, Oct. 1962, 1763-1767.
16.
Gases and Solids
: The immersion of silica, alumina,
and titania with particle size and outgassing temperature. U.S.A. The heats of immersion of the three substrate materials
in hexane have been measured as a function of particle sizeand outgassing temperature. The results are interpreted in terms of van der Waals and ion-induced dipole interactions. (Authors) W. H. Wade and N. Hackerman, 1823-l 826.
J. Phys.
Chm.,
66, Oct. 1962,
16 485. Adsorption
of argon on graphitized carbon black. Surface area and heats and entropies of adsorption. U.S.A. Adsorption isotherms of argon on the highly graphitized
carbon black P33 (2700”) between 90 and 137°K are presented. Estimates of the surface area of the adsorbent and heats and entropies of adsorption computed from the data are discussed. The present results are compared with quantities obtained through the virial coefficient treatment of physical adsorption. (Authors)
16 481. Multilayers of argon and nitrogen on hexagonal boron nitride. U.S.A. Multilayer adsorption isotherms of argon on boron nitride have been determined at 66.0, 68.9, and 75.9”K. In addition, multilayer isotherms of nitrogen on boron nitride have been determined at 63.30 and 65.79”K. Isosteric heats of adsorption have been obtained and are compared with the isosteric heats of adsorption of argon on graphite (P-33). The interaction energies of adsorption are determined for argon on P-33 and boron nitride by means of the Singleton-Halsey isotherm equation and are compared with the interaction energies calculated by dispersion energy summations. The calculated and observed interaction energies for argon-boron nitride are in good agreement. The observed interaction energy of argon with graphite is larger than that calculated. This discrepancy (Author) is discussed in terms of various interaction theories.
16 486. An infrared study of a silica-alumina surface. U.S.A. In highly dehydrated samples of silica-alumina a single band is observed in the OH stretching region. The results imply that a single surface hydroxyl group type attached to silicon atoms predominates in these samples. The interaction of water with the surface of highly dehydrated silica-alumina is investigated, and it is established that fixedly adsorbed water is held on acidic sites far enough removed from surface hydroxyl groups that hydrogen-bonding to these groups does not occur. The bands in the silica-alumina spectrum from 4000-1000 cm-’ are tentatively assigned, including one which is thought to be (Author) due to the Al0 linkage in an acidic surface group.
R. A. Pierotti,
M. R. Basila, J. Phys.
J. Phys.
Chem.,
66, Oct. 1962, 1810-1815.
J. R. Sams, et al., J. Phys.
Chem.,
Gem.,
66, Nov.
66, Nov.
1962, 2154-2158.
1962, 2223-2228.
chloride
16 films.
66, Nov.
1962.
16 on low energy solids. I : Adsorption of argon and nitrogen on polytetrafluoro-
482. Physical adsorption
carbon tetrafluoride, ethylene. U.S.A. Carbon tetrafluoride,
argon and nitrogen, at temperatures near their respective boiling points, are adsorbed on polytetrafluoroethylene with isosteric heats of adsorption only slightly greater than the corresponding latent heats of condensation. In all cases, the adsorbates are mobile, nitrogen retaining some “ super mobility “. Film pressures at a coverage representing one statistical monolayer are 9.5 to 10 ergs/cml. Additional monolayers are adsorbed with abnormally low isosteric (Author) heats indicating multilayer films of low density. D. Graham,
J. Ph.17.r. Chem.,
66, Oct. 1962, 181.5-181X.
487. Adsorption (U.S.A.)
of water
vapor
P. G. Hall and F. C. Tompkins,
on potassium J. Phys.
Chern.,
2260-2262. 16 488. Infrared and volumetric data on the adsorption of ammonia, water, and other gases on activated iron (III) oxide. U.S.A. Infrared spectra in the 2 to 13~ range have been
obtained of NH,, H,O, H,S, EtOH, and Et,0 chemisorbed on N,, O,, H,, CO, SO,, Cl,, C,H, and C,H( do not a-FelO,. chemisorb at 25” on a-Fe,O,. H,O chemisorbs by dissociating to form a OH- ion and a proton which reacts with a surface 0-* ion to produce another OH- ion. NH, upon chemisorption