Desorption of Water, Methyl Alcohol and Carbon Tetrachloride from Silica-gel Surfaces

Nature ◽  
1963 ◽  
Vol 198 (4884) ◽  
pp. 988-989 ◽  
Author(s):  
B. B. DARLOW ◽  
R. A. ROSS
Keyword(s):  
Carbon Tetrachloride ◽  
Silica Gel ◽  
Methyl Alcohol

scholarly journals The sorption of methyl and ethyl alcohol by silica gels

1934 ◽  
Vol 146 (856) ◽  
pp. 129-140 ◽  
Keyword(s):  
Silica Gel ◽  
Ethyl Alcohol ◽  
Methyl Alcohol ◽  
Ferric Oxide ◽  
Silica Gels ◽  
Adsorptive Capacity ◽  
Incomplete Removal ◽  
Higher Temperature ◽  
Permanent Gases ◽  
Hysteresis Phenomena

The original object of the present research was to investigate the sorption of methyl alcohol by silica gel, in order to compare the isothermals with those of water and ethyl alcohol, which had been determined by Lambert and Foster. Owing to the fact that the supply of gel used for this earlier work had been exhausted, it as necessary to examine a number of other specimens. One of these, which like the original gel, was a commercial product, was found to take up a larger amount at saturation, and also to exhibit hysteresis phenomena which were not observed with the original gel. Unfortunately it was impossible to find a sample giving exactly the same shape of isothermal as the original gel, although some specimens known to belong to the same batch gave very similar curves. One of these was selected for the present work, and an examination has been made of the isothermals of methyl and ethyl alcohols on these two types of silica gel at 25° C. The fact that one specimen showed hysteresis provided a suitable occasion further to confirm the view, always maintained by Lambert and the author, that these phenomena are in no way due to incomplete removal of permanent gases or other impurities from the systems. In previous work with silica and ferric oxide gels, evacuation was carried out at 150° C, which is actually the optimum temperatures of activation for the latter gel, the adsorptive capacity of which decreases rapidly when higher temperatures are employed. Silica gels, however, will withstand a much higher temperature with comparatively little diminution in capacity, and in the present work it has been shown that the hysteresis phenomena are not affected by raising the temperature of the initial evacuation to 250° C or even to 350° C. It has also been shown that the phenomena persist after continued "flushing out" of the gel with methyl or ethyl alcohol vapour. (McBain suggested that the hysteresis observed by Lambert and Clark with benzene on ferric oxide gel would not have ocucrred if the gel had been flushed out with benzene before the isothermals were determined.)

THE TESTING OF ACTIVATED CHARCOALS BY THE ISOPIESTIC METHOD

1949 ◽  
Vol 27b (1) ◽  
pp. 25-34 ◽  
Author(s):  
H. Sheffer ◽  
K. T. Waldock ◽  
J. B. Ferguson
Keyword(s):  
Carbon Tetrachloride ◽  
Rapid Method ◽  
Methyl Alcohol ◽  
Isopiestic Method ◽  
Mustard Gas ◽  
Flow Method

The isopiestic method has been applied to the testing of activated charcoals. The ratios of vapor adsorbed at saturation were found to agree well with the ratios of the activities obtained by a flow method. The sorptive capacities of nine different activated charcoals for carbon tetrachloride water, amyl chloride, benzene, methyl alcohol, n-hexane, mustard gas, and phosgene have been compared. A simple, rapid method for testing charcoals is suggested.

The theory of condensation of supersaturated vapours in the absence of ions

1953 ◽  
Vol 220 (1140) ◽  
pp. 132-141 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Methyl Alcohol ◽  
Rapid Heating ◽  
Molecular Complexes ◽  
Cloud Chamber ◽  
Appreciable Amount ◽  
Liquid Droplets ◽  
Critical Supersaturation ◽  
Chamber Measurements ◽  
Alcohol Benzene

A brief review of the condensation theory of Becker & Döring (1935) and Frenkel (1946) is given. It is shown that the theory is subject to the limitation that it assumes that small molecular complexes behave like liquid droplets. This is not the case for complexes consisting of a few molecules only, so that the rate of condensation expected from the theory may be altered by an appreciable amount. The Becker & Döring expression for critical supersaturation is compared with the cloud-chamber measurements of Volmer & Flood (1934), taking into account the rapid heating of the gas after the fast expansion. It is found to be in approximate agreement for water and some of the alcohols, but methyl alcohol, benzene and carbon tetrachloride show large discrepancies. More measurements of critical supersaturations are needed.

scholarly journals The second virial coefficients of organic vapours

1949 ◽  
Vol 196 (1044) ◽  
pp. 113-125 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Hydrogen Bonding ◽  
Carbon Tetrachloride ◽  
Diethyl Ether ◽  
Methyl Alcohol ◽  
Virial Coefficients ◽  
Dipole Interaction ◽  
Conductivity Data ◽  
Second Virial Coefficients ◽  
Critical Data

The compressibilities of a num ber of organic vapours have been measured at pressures up to 1 atm. and temperatures ranging from 40 to 130° C. The observed second virial coefficients are compared with values calculated from the critical data by the Berthelot equation. The results show two distinct classes of behaviour. Class I is shown by ethane, ethylene, n -hexane, cyclohexane, benzene, diethyl ether, ethyl chloride, chloroform and carbon tetrachloride, where the measured second virial coefficients are in agreement with the calculated values. Class II by acetaldehyde, acetone, acetonitrile, methyl alcohol, where the measured second virial coefficients are consistently very much higher than the calculated values. It is concluded that the vapours of polar substances for which the energy of attraction between molecules, due to dipole interaction or to hydrogen bonding, is larger than kT undergo dim erization. This view is supported by thermal conductivity data. The range of validity of the Berthelot equation for both non-polar and polar vapours is examined.

Spectra of flames supported by free atoms

1952 ◽  
Vol 213 (1114) ◽  
pp. 366-379 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Methyl Alcohol ◽  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Electronic Excitation ◽  
Carbon Disulphide ◽  
Mechanism Of Formation ◽  
Organic Halides ◽  
Reaction Zones ◽  
Very High

The spectra of the ‘atomic flames’ of organic compounds with the products of discharges through oxygen, hydrogen and water vapour have been examined. Hydrocarbons give bright flames with water products but not, contrary to previous reports, with dry atomic hydrogen. Carbon tetrachloride and other organic halides and also carbon disulphide do give bright flames with hydrogen. The rotational intensity distribution in the OH band in most atomic flames corresponds to a very high temperature, around 8000° K; it is high for methyl alcohol with water products, but only around 2500° K for methyl alcohol with atomic oxygen. The flame of acetylene with products from heavy water, D 2 O, gives mainly OD and CD rather than OH and CH bands. The mechanism of formation and excitation of CH and OH in flames is discussed. When iron carbonyl is introduced into atomic flames very high electronic excitation of iron atoms is observed, as in the reaction zones of ordinary premixed flames; this high excitation is also observed for the flame of carbon tetrachloride with atomic hydrogen.

Sign in / Sign up

Export Citation Format

Share Document