John Walter

Multiple Adsorption from Solutions

The general theory of the adsorption of solutes from solutions which are treated by a process similar to that employed in chromatography is presented. By assuming a chemical equilibrium between adsorbed material and the solution, the adsorption equations can be solved explicitly. A detailed discussion of the two‐component problem is given; the many‐component problem and the extension of the theory to more general adsorption isotherms are considered briefly.The general theory of the adsorption of solutes from solutions which are treated by a process similar to that employed in chromatography is presented. By assuming a chemical equilibrium between adsorbed material and the solution, the adsorption equations can be solved explicitly. A detailed discussion of the two‐component problem is given; the many‐component problem and the extension of the theory to more general adsorption isotherms are considered briefly.

The Optical Activity of Secondary Butyl Alcohol

A calculation of the optical activity of secondary butyl alcohol is presented based upon a one‐electron model. The chromophoric electron is considered to be one of the nonbonding electrons on the oxygen atom. This electron is considered to be moving in a field of the other nuclei and electrons considered as charge distributions. The fields of the other electrons are obtained from the Slater type eigenfunctions for the various atoms. This amounts to a rough solution of the Hartree approximation for the chromophoric electron. The results obtained are somewhat larger or somewhat smaller than the experimental value depending on the exact orientation of the groups in their rotation about single bonds. The assignment of an absolute configuration in these calculations follows provided the exact orientation of the rotating groups is known. The orientations which we consider most likely lead to an assignment of the absolute configuration in agreement with that of Kuhn.

Absorption of Microwaves by Gases. II

The absorption coefficients and dielectric constants of sixteen gases have been measured at the two wave‐lengths λ=1.24 cm and λ=3.18 cm. The gases are H2S, COS, (CH3)2O, C2H4O, C2H5Cl, SO2, NH3, six halogenated methanes and three amines. Certain improvements in technique are described; these improvements permit detection of absorption coefficients as small as 0.2×10−4 cm−1 and measurement of larger coefficients with an accuracy of ± 5 percent. The measured dielectric constants at these wave‐lengths are essentially equal to the static values. A quantitative interpretation of the absorption coefficients in terms of the known structure and spectra of the individual molecules is given. The theory indicates that all non‐planar molecules which possess a permanent dipole moment should show appreciable absorption in the microwave region.

Rate‐Dependent Chromatographic Adsorption

The process of chromatographic adsorption is studied from the kinetic viewpoint, assuming a bimolecular reaction between adsorbent and solute. Boundaries characteristic of equilibrium adsorption are obtained only if the time of passage of the solution through the column is greater than the half‐life of the reaction by a factor of at least one hundred.

A Partition Function for Normal Liquids

A theory of liquids designed to account for rate as well as thermodynamic properties is given. By considering the molecules of the liquid to be distributed at random among solid‐like and gas‐like equilibrium positions, where the introduction of a new equilibrium position requires a volume increase of about ⅛ the molecular volume, it is possible to derive an explicit partition function for liquids. The model embodies the features previously used in the theory of viscosity and diffusion. The thermodynamic properties of argon, nitrogen and benzene are calculated and compared with experiment.

Optical Activity of the Sugars

The optical activities of some pentose sugars have been calculated by using the one‐electron theory. The relative signs calculated agree in every case with those experimentally observed while the agreement as to magnitude is satisfactory. Some general considerations concerning the superposition rules are presented. It is shown that the rule is derivable upon the basis of the additivity of the vicinal effects. In addition certain requirements on the structure of the pyranose ring must be fulfilled.

The Molecular Structure of Isobutane

The two published electron diffraction investigations of isobutane led to slightly conflicting results. We have repeated the calculation of the theoretical scattering curves using Z—F instead of Z for the atom form factor and including the temperature factor. The final results are: C–C distance, 1.54±0.02A; C–C–C angle 111° 30′±2°.

The Radial Distribution Method in Electron Diffraction

A new radial distribution function for use in interpreting the electron diffraction photographs of gas molecules has been obtained. Instead of replacing the inverted Fourier integral by a sum the integration is performed by assuming that the shapes of the maxima and minima are those of cosine functions. The amount of scattering matter r2D(r) is calculated rather than the density D(r). Comparison between radial distribution functions calculated by this method and by other methods is made for a diatomic molecule, a nonlinear triatomic molecule (to test resolving power), a linear triatomic molecule and carbon tetrachloride.