scholarly journals The system benzene-methyl alcohol : ?b densities, refractive indices, boiling points, and specific heats.

1941 ◽  
Author(s):  
Samuel Rosenberg, 1918-
Keyword(s):  
Methyl Alcohol ◽  
Refractive Indices ◽  
Specific Heats ◽  
Boiling Points

ECONOMY OF TIME IN LABORATORY DISTILLATION

1931 ◽  
Vol 5 (4) ◽  
pp. 455-465
Author(s):  
D. F. Stedman
Keyword(s):  
Methyl Alcohol ◽  
Critical Value ◽  
Complete Separation ◽  
Volatile Constituent ◽  
Reflux Ratio ◽  
Correction Factors ◽  
Boiling Points ◽  
Efficient Column ◽  
The Difference ◽  
Theoretical Amount

The mathematics of fractional distillation of ideal mixtures has been condensed, so that the most economical "reflux ratio" for any such mixture may be decided at once.Particular use is made of the "critical reflux ratio" for any mixture, above which even an infinite column cannot obtain complete separation; and the relation of this critical value to the most economical value for any particular case is given.Some of the conclusions with respect to the infinite column were tested by means of a mixture of methyl and ethyl alcohols using a particularly efficient column. It was found that the vapor produced in the still contained slightly more than the theoretical amount of methyl alcohol, and the magnitude of such error is illustrated from previous work on glycerine solutions.The results are given in the form of a graph of the "critical reflux ratio" for the case where the most volatile constituent boils at 100 °C., and the difference between the boiling points varies from 0.25 °C. to 32 °C., the concentration of the most volatile constituent also being included from 0.001 to 1.0.A table of correction factors is also given, showing the factor by which the "critical reflux ratio" should be varied to produce the greatest economy of time for any particular case.

scholarly journals Critical and co-operative phenomena. V. Specific heats of solids and liquids

1940 ◽  
Vol 174 (956) ◽  
pp. 102-109 ◽  
Keyword(s):  
Free Energy ◽  
Thermal Expansion ◽  
Quantum Effects ◽  
Dense Gas ◽  
Critical Temperatures ◽  
Simple Method ◽  
Specific Heats ◽  
Lennard Jones ◽  
Boiling Points ◽  
Satisfactory Theory

In the first two papers in this series (Lennard-Jones and Devonshire 1937-8) we developed a simple method of calculating the free energy of a dense gas or a liquid in terms of interatomic forces. We used this to calculate critical temperatures and also vapour pressures and boiling-points. In later papers (Lennard-Jones and Devonshire 1939) we showed that the model used in the earlier papers was more appropriate to a solid than to a liquid, and that to obtain a satisfactory theory for a liquid we must modify it by introducing the concept of disorder. In this way we were able to account satisfactorily for the phenomenon of melting. In this paper we propose to use the expression for the free energy obtained in the earlier papers to calculate the specific heats of solids and liquids, and also the coefficients of thermal expansion and compressibilities. As before, we confine ourselves to the case when quantum effects are negligible.

scholarly journals Atomic specific heats between the boiling points of liquid nitrogen and hydrogen. I.—The mean atomic specific heats at 50° absolute of the elements a periodic function of the atomic weights

1913 ◽  
Vol 89 (609) ◽  
pp. 158-169 ◽  
Keyword(s):  
Periodic Function ◽  
Specific Heat ◽  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Liquid Hydrogen ◽  
Specific Heats ◽  
Boiling Points ◽  
Royal Institution ◽  
Series Of Experiments ◽  
The Mean

A method of determining the specific heat of substances at low temperatures was described in a paper on “Studies with the Liquid Hydrogen and Air Calorimeter,” also in the abstract of a lecture delivered at the Royal Institution entitled“ Liquid Hydrogen Calorimetry,” where the apparatus then used is illustrated. Continuing the use of the same method, but with some modification of the apparatus, the investigation has been extended to a large number of inorganic and organic bodies. In this later series of experiments, the measurements of the specific heats of materials by the liquid hydrogen calorimeter were made over a range of temperature from boiling nitrogen to boiling hydrogen, a fall of temperature of some 57° Abs.

Étude statistique des effets de solvant. III. Calcul et interprétation de paramètres empiriques de polarité à partir de propriétés physicochimiques des solvants purs

1985 ◽  
Vol 63 (12) ◽  
pp. 3492-3498 ◽  
Author(s):  
M. Chastrette ◽  
J. Carretto
Keyword(s):  
Dipole Moments ◽  
Energy Levels ◽  
Dielectric Constants ◽  
Refractive Indices ◽  
Aprotic Solvents ◽  
Etude Statistique ◽  
Frontier Orbitals ◽  
Boiling Points ◽  
Protic Solvents ◽  
Polarity Of Solvents

Using multivariational statistical methods, the calculation and interpretation of empirical parameters of the polarity of solvents has been reexamined. The size of the sample used (57 aprotic solvents and 24 protic solvents) assures that it is representative. For each solvent, the data tabulated include some physical constants (dielectric constants, dipole moments, refractive indices, molar refractions, boiling points, Hildebrand's δ parameters) or theoretical values (energy levels of frontier orbitals). The methods used are factorial analysis and multiple regression. The results obtained show that, for the aprotic solvents, the parameter ET is a measure of the polarity, of the polarizability, and of the cohesion of the solvent to the extent of 43, 39, and 18% respectively. For the parameter π*, these proportions are respectively 53, 18, and 29%. For the protic solvents, the parameter ET is explained by the same variables except for 5 solvents more acidic than water; this anomaly is explained by the basicity of the oxygen of the betaine used to define ET.

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