Heterogeneous Interactions of Methylamines on Porous Adsorbents. Part III. The Adsorption Characteristics of Methylamines on γ-alumina and Types '3A' and '13X' 'Molecular Sieves'

The adsorption characteristics of mono-, di-, and trimethylamine on γ-alumina have been investigated and adsorption isotherms in the regions of their boiling points determined, along with isothermal calorimetric heats of adsorption up to monolayer coverage (θ = 1). From the initial heats of adsorption of 21.6 to 32.4 kcal/mol θ = 0.05, and the strong retention of the amines adsorbed at low pressures, chemisorption is considered to occur at θ < 0.20. The maxima and minima displayed in the heat curves are discussed in terms of adsorbate–adsorbate interactions at sub-monolayer coverage levels. Adsorption isotherms for di-and tri-methylamine on Linde 'molecular sieves' '13X' and '3A' have been measured also, along with the trimethylamine heat curves for these materials.

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Heterogeneous Interactions of Methylamines on porous Adsorbents Part II. Interactions on Silica–Alumina and Silica Gel Surfaces of Di- and Tri-methylamine in the Region of their Boiling Points

Canadian Journal of Chemistry ◽

10.1139/v72-395 ◽

1972 ◽

Vol 50 (15) ◽

pp. 2451-2456 ◽

Cited By ~ 3

Author(s):

W. G. Cook ◽

R. A. Ross

Keyword(s):

Silica Gel ◽

Surface Coverage ◽

Adsorbed Layer ◽

Silica Gels ◽

Heats Of Adsorption ◽

Boiling Points ◽

Silica Alumina ◽

Desorption Isotherms ◽

Adsorption Desorption ◽

Heterogeneous Interactions

The adsorption of di- and tri-methylamine has been studied at 280 and 276°K, respectively, on a range of silica gels and on silica–alumina. Adsorption–desorption isotherms and isothermal calorimetric heats of adsorption were measured. Heats of adsorption for di-methylamine on silica gel varied from 29.0 kcal/mol at θ = 0.05 to 12.0 kcal/mol at monolayer completion, while for silica–alumina the heats fell from 31.4 to 9.0 kcal/mol between these same values of surface coverage. For tri-methylamine on silica gel, heats fell from 21.0, θ = 0.05, to 10.3 kcal/mol, θ = 1.00, while heats of 21.4 and 9.9 kcal/mol, respectively, were found at these same surface coverages on silica–alumina. The values of the heats of adsorption are discussed in terms of interactions in the adsorbed layer which are believed to be influenced by the pore sizes in the adsorbent and by the basicity of the amine molecules.

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Uncertainty of adsorption isotherms of n-hexane on active charcoal in the region of small pressures and its influence on calculations of heats of adsorption

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19713555 ◽

1971 ◽

Vol 36 (11) ◽

pp. 3555-3562 ◽

Cited By ~ 1

Author(s):

J. Juliš ◽

J. Dědek ◽

P. Fott

Keyword(s):

Adsorption Isotherms ◽

Active Charcoal ◽

Heats Of Adsorption

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The influence of pressure on the boiling points of metals

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1910.0037 ◽

1910 ◽

Vol 83 (565) ◽

pp. 483-491 ◽

Cited By ~ 9

Keyword(s):

Atmospheric Pressure ◽

Boiling Point ◽

High Vacuum ◽

Similar Type ◽

Exact Relation ◽

Reduced Pressure ◽

Boiling Points ◽

Experimental Values ◽

Low Pressures ◽

Very High

Part I. — Pressures below 760 mm . In a previous communication (‘Proc.’, A, vol. 82, 1909, p. 396) the approximate boiling points of a number of metals were determined at atmospheric pressure. Apart from the question of finding the exact relation between the boiling point and pressure, it is an important criterion of any method for fixing the temperatures of ebullition to demonstrate that the experimental values obtained are dependent on the pressure. It is specially desirable when dealing with substances boiling at temperatures above 2000° to have some evidence that the points indicated are true boiling points. Previous work on the vaporisation of metals at different pressures has been confined to experiments in a very high vacuum except for metals like bismuth, cadmium, and zinc, which boil at relatively low temperatures under atmospheric pressure. The observations were limited to very low pressures on account of the difficulty of obtaining any material capable of withstanding a vacuum at temperatures over 1400° and the consequent necessity for keeping the boiling point below this limit by using very low pressures. Moreover in the case of the majority of the metals, e. g. , copper, tin, ebullition under reduced pressure has never been observed. The difficulties indicated above were avoided by using a similar type of apparatus to that previously described, and arranging the whole furnace inside a vacuum enclosure, thus permitting of the use of graphite crucibles to contain the metal.

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