Index of content:
Volume 10, Issue 12, 01 December 1942
Infra‐Red and Raman Spectra of Polyatomic Molecules XVII. Methyl‐d 3‐Alcohol‐d and Methyl‐d 3‐Alcohol10(1942); http://dx.doi.org/10.1063/1.1723650View Description Hide Description
CD3OD and CD3OH have been prepared and their infra‐red spectrum in the range from 2.5μ to 18μ has been measured. The Raman spectrum of CD3OD has been observed. CH3OH and CH3OD have been reinvestigated and an assignment for all four methyl alcohols has been given.
Spectroscopic Studies of the Simpler Porphyrins IV. The Absorption and Fluorescence Spectra of ms‐Tetra(3′,4′‐methylenedioxyphenyl)porphine of HCl Number Four and of Its AgC5H5N, Zn, and Ni Complex Salts10(1942); http://dx.doi.org/10.1063/1.1723651View Description Hide Description
The molecular absorption coefficients of ms‐tetra(3′,4′‐methylenedioxyphenyl)porphine and the AgC5H5N, Zn, and Ni complex salts have been measured over the visible region of the spectrum. The curves representing the absorption coefficients as a function of the wave‐length are shown. The spectra of this porphyrin and its metal complex salts are quite similar to those of ms‐tetraphenylporphine and its corresponding metal complex salts. The fluorescence spectra of these substances have also been studied. All four substances fluoresce in the red region of the visible spectrum. Curves showing relative intensity of fluorescence as a function of wave‐length are shown for the parent substance and the Zn complex salt. The fluorescence of the AgC5H5N and Ni complex salts is so weak that intensity measurements could not be made.
The Differences in the Vapor Pressures, Heats of Vaporization, and Triple Points of Nitrogen (14) and Nitrogen (15) and of Ammonia and Trideuteroammonia10(1942); http://dx.doi.org/10.1063/1.1723652View Description Hide Description
The differences in the vapor pressures of natural nitrogen and samples containing 34.6 percent nitrogen‐15 were measured by a differential method and were found to be given by log P 1/P 2=(0.2474/T)−0.001994 where 1 refers to the natural nitrogen and 2 refers to the heavy sample. The difference in the heats of vaporization of the two samples was calculated to be 1.14 calories, that of the heavy sample being higher. The triple point pressures were measured and found to be 9.386 cm of Hg and 9.378 cm of Hg, respectively. From this the difference in the triple points was calculated to be 0.020°K. Assuming that Raoult's law may be used, the ratio of the vapor pressures and the difference in the heats of vaporization of the two pure isotopes, nitrogen‐14 and nitrogen‐15, were found to beThe triple point of the pure nitrogen‐15 was found to be 0.058° higher than that of nitrogen‐14 and the boiling point 0.052° higher. The differences in the vapor pressures of solid natural ammonia and of solid trideuteroammonia containing 98 percent deuterium were measured and found to be given byThe vapor pressures of the liquid ammonias were found to follow the equationThese two equations agree at the triple point. The difference in the heats of sublimation was calculated to be 227 calories, while the difference in the heats of vaporization is 212 calories, the values for the trideuteroammonia being higher than those for ammonia. The triple point pressures were found to be 4.557 cm of Hg for ammonia and 4.822 cm of Hg for the trideuteroammonia. This corresponds to triple point temperatures of 195.68°K and 198.79°K, respectively. The boiling point of the trideuteroammonia was found to be 2.37° higher than that of the ammonia.
10(1942); http://dx.doi.org/10.1063/1.1723653View Description Hide Description
The differences in the thermodynamic properties of liquid nitrogen (14) and liquid nitrogen (15) are discussed on the basis of several Debye‐like models. The quantum mechanical effects are found to be greater than one could expect from an harmonic oscillator model. Other factors affecting these properties are considered.
10(1942); http://dx.doi.org/10.1063/1.4757202View Description Hide Description
The purpose of this work was to obtain, by means of measurements of electromotive force, information on the behavior and nature of ions present in liquids of low dielectric constant. These measurements were made on silver and silver‐silver chloride concentration cells containing solutions whose dielectric constants were as low as 2.6 and whose specific conductances were as low as The results of these tests were supplemented by conductivity measurements on all the solutions involved. From the data obtained, approximate values for the dissociation constants and electrochemical transference numbers of the electrolytes for various electrolyte‐solvent combinations were deduced.
10(1942); http://dx.doi.org/10.1063/1.1723654View Description Hide Description
The photolysis of propionaldehyde at λλ2537, ∼2900, and ∼3200A has been studied by the Paneth mirror method. The alkyl radicals produced are exclusively ethyl; no atomic hydrogen can be detected by the guard mirror method in amounts exceeding 2 percent of the total number of mirror‐active particles present. The yield of C2H5 radicals has been determined and compared with the yields of CO, H2, and C2H6. The results are most readily interpreted in terms of competing primary decomposition processes producing free radicals in one reaction and ultimate molecules in another. Whereas the former reaction increases in importance at shorter wave‐lengths, the latter becomes less significant. On the other hand, an explanation for the results can be given on the basis of a mechanism involving only the production of free radicals in the primary process at all wave‐lengths. The role played by excited propionaldehyde molecules (of life which may be >10−3 sec.) and by freshly formed (energy‐rich) C2H5 and HCO radicals on their first collision is also considered. The mechanism of energy transfer within the propionaldehyde molecule is discussed and it is shown that the products of the primary decomposition are probably determined by geometric considerations and by the relative heights of the dissociation levels involved in the normal state.
10(1942); http://dx.doi.org/10.1063/1.1723655View Description Hide Description
The experimental heat capacity data for crystalline Cl2, CO2, SO2, SCO, N2O, C2N2, C6H6, C2H4, and CH3Br have been compared with the results of calculations made employing a semitheoretical method suggested by Lord, Ahlberg, and Andrews and amplified by Lord. Good agreement between the calculated and experimental results is obtained.
10(1942); http://dx.doi.org/10.1063/1.1723656View Description Hide Description
10(1942); http://dx.doi.org/10.1063/1.1723657View Description Hide Description
(1) Silver oxalate precipitates age rapidly, and the process is not greatly impeded by adsorption of wool violet or 3,3′‐diethyl‐9‐methylthiacarbocyanine. (2) Gelatin markedly decreases the rate of reaction between silver oxalate and hydroxylamine in slightly acidsolution. A break is obtained in the rate‐gelatin curve corresponding to a definite adsorption layer. The thickness of this layer is the same for silver oxalate, silver chloride, and silver thiocyanate. (3) The dye, 3,3′‐diethyl‐9‐methylthiacarbocyanine, has a much smaller effect than gelatin upon the reaction rate. (4) The effect of bromide ion upon the gaseous products of the reaction between silver oxalate and hydroxylamine in alkaline solution is considerably smaller than in the corresponding reactions of silver chloride and thiocyanate.
An Empirical Equation for Thermodynamic Properties of Light Hydrocarbons and Their Mixtures II. Mixtures of Methane, Ethane, Propane, and n‐Butane10(1942); http://dx.doi.org/10.1063/1.1723658View Description Hide Description
An empirical equation is given for the isothermal variation with density of the work content of hydrocarbon mixtures in the gaseous or liquid state. From this fundamental equation are derived (a) an equation of state, (b) an equation for the fugacity, (c) an equation for the isothermal variation of the enthalpy, and (d) an equation for the isothermal variation of the entropy. These equations summarize P‐V‐T‐xproperties of the gaseous or liquid phase, liquid‐vapor equilibria, critical properties,latent heats of evaporation, and heats of mixing. The equation is a generalization to mixtures of the equation for pure hydrocarbons given in the first paper of this series. Methods are proposed for determining the parameters in the equation for mixtures from the parameters in the equation for pure hydrocarbons. A comparison is made between observed properties of mixtures and those predicted by the equations. These comparisons show that the equations provide a satisfactory practical summary of the volumetric properties and liquid‐vapor equilibria of mixtures of methane, ethane, propane, and n‐butane.