Ionic association in hydrogen-bonding solvents

Studies on ionic association in hydrogen-bonding solvents including water, aliphatic alcohols, fluorinated alcohols, formamide, ethylene glycol, and propanol-acetone mixtures are compared. Data were derived from measurements of conductivity, ultrasonic absorption, and viscosity of electrolyte solutions and diffusion of nonelectrolytes. It is concluded that electrolyte solvents can be divided into three categories according to whether they solvate effectively cations only, anions only, or both cations and anions. Water and most other hydrogenbonding solvents constitute the third class, a group in which patterns of ionic aggregation are very similar. Fluorinated alcohols belong to the second class, showing significantly different ion-pairing behavior.This paper was presented at the symposium, The Physical Chemistry of Aqueous Systems, held at the University of Pittsburgh, Pittsburgh, Pennsylvania, June 12–14, 1972, in honor of the 70th birthday of Professor H. S. Frank.     

Propionaldehyde: ab initio and semi-empirical calculations

The internal rotation of propionaldehyde about the 1–2 bond has been studied by means of ab initio calculations. The most stable conformer has methyl and carbonyl eclipsed. Increasing the 1–2 dihedral angle to 60°, 120°, and 180° gives energies of 1.7, 0.4, and 0.7 Kcal/mol, respectively. The agreement with force field calculations and with experiment is reasonable.     

Dirichlet series with functional equations and arithmetical identities

Exploiting the functional equation of Hecke-type associated with a function satisfying a modular relation with a residual function as developed in Bochner (J Indian Math Soc 16:99–102, 1952), Chandrasekharan and Narasimhan (Ann Math 74:1–23, 1961) derived the equivalence of the functional equation to two arithmetical identities. Hawkins and Knopp (Contemp Math 143:451–475, 1993) showed the equivalence of the functional equation to modular integrals with rational period functions of weight 2k, \(k \in \mathbb {Z}^+\) on the theta group \(\Gamma _\vartheta \). The aim of the current work is to show that results analogous to those of Chandrasekharan and Narasimhan can be developed in the Hawkins and Knopp context, but with respect to the full modular group \(\Gamma (1)\), rather than the theta group \(\Gamma _\vartheta \).     

Nickel catalysts for the hydrodeoxygenation of biodiesel

A number of nickel and nickel-copper catalysts for the hydrodeoxygenation of fatty acid esters (biodiesel) were studied. The CeO₂ and ZrO₂ oxides and the CeO₂-ZrO₂ binary system were used as supports. The Ni-Cu/CeO₂-ZrO₂ catalyst exhibited the highest activity; it allowed us to quantitatively convert biodiesel into linear alkanes under mild conditions (290–320°C, 1.0 MPa). It was found that the selectivity of the formation of the main product (heptadecane) was 70–80%. The main correlations between the nature of catalysts and their activity under conditions of the target reaction were determined using temperature-programmed reduction, X-ray diffraction analysis, and electron microscopy. It was hypothesized that the high activity of Ni-Cu/CeO₂-ZrO₂ in the test reaction can be explained by the presence of a Ni_{1 − x} Cu _x (x = 0.2–0.3) solid solution as a constituent of the active component of the catalyst.     

Cosmology withG and Λ coupling scalars

Cosmology with the gravitational and cosmological constants generalized as coupling scalars in Einstein's theory is considered. A general method of solving the field equations is given. Fifteen exact solutions for zero pressure models satisfyingG=G ₀(R/R ₀) ⁿ are given in the Appendix; they are briefly discussed.     

Photoconductivity of strontium oxide containing F+ centres

Photoconductivity has been measured from the F⁺ absorption band in electron and proton irradiated SrO. The measurements were made over the spectral range from 2 to 4 eV and over the temperature range from 65 to 180 K. The photocurrent excited in the F⁺ band appears to be carried by electrons and has a thermal activation energy of about 0.10 eV.