The ESR Study of the Ion Pair Complexes of m-Iodonitrobenzene with Alkali and Alkaline Earth MetalsNakamura, Kazuo
doi: 10.1246/bcsj.40.1pmid: N/A
The ESR spectra of the ion-pair complexes of the m-iodonitrobenzene anion with alkali and alkaline earth cations were measured. Cation-induced variations in the nitrogen and proton splitting constants were found. When the observed alkali metal splittings were related to the back-transferred charge, ρ, on the ns-shell of each metal, ρ increased in the sequence: Li<Na<K<Rb<Cs at 20°C. The solvent and the temperature effects on alkali-metal splitting varied with the alkali metal. The Cs and Rb splitting constants increased in the sequence: DME<THF<THP solutions, and were independent of the temperature. The Na and Li splitting constants decreased in the above sequence of solvents. With a lowering of the temperature, the Na splitting constant decreased while the Li splitting constant increased. The K splitting constant was independent of both the temperature and the solvent. These results were found in the ion pairs of other halogeno-nitrobenzenes, also.
The Heats of Dilution in Atactic Polymethyl Methacrylate SolutionsKagemoto, Akihiro; Murakami, Sachio; Fujishiro, Ryoichi
doi: 10.1246/bcsj.40.11pmid: N/A
In order to ascertain the dependence of the interaction parameter, χH, between the polymer and the solvent molecules on the polymer concentration, the heats of dilution in an atactic polymethyl methacrylate solution have been measured for the polymers with the degrees of polymerization of 3000 and 7800. It was found that the values of χH obtained are dependent on the concentration in all the solvents used, as in the solutions of polystyrene and polybutadiene reported as in previous papers. χH depends also on the molecular weight, this is in agreement with the suggestion by Huggins (J. Am. Chem. Soc., 86, 3535 (1964)).
Study of Dielectric Relaxation Mechanism in Some Substituted PyridinesMehrotra, N K; Saxena, M C
doi: 10.1246/bcsj.40.19pmid: N/A
The relaxation times of 2-chloro-, 2-bromo-, 3-bromo-, 2-methyl-, 2-acetyl- and 2-hydroxy-pyridines have been determined in the 3 cm microwave region at 20°C using benzene as solvent. It has been concluded from the relaxation times of 2-chloro-, 2-bromo-, 3-bromo- and 2-methylpyridines that these rigid molecules relax predominantly by the process of over-all molecular rotation. The comparatively small relaxation times of 2-acetyl- and 2-hydroxypyridines suggest that these non-rigid molecules relax by both molecular as well as intramolecular rotations. The free energies of activation for dipole orientation for the compounds investigated are always found to be smaller than those for viscous flow, because the process of dipole orientation involves only rotation, while the process of viscous flow involves both rotation and translation.
The Electronic Structure of Peptide and the Base Components of Nucleic Acids in the Triplet StateImamura, Akira; Fujita, Hiroko; Nagata, Chikayoshi
doi: 10.1246/bcsj.40.21pmid: 6074287
The electronic structures of β-naphthol, the base components of nucleic acids, and peptide have been calculated for the ground, singlet-excited, and triplet-excited states by means of the ASMO SCF CI method. The calculated π electron density of β-naphthol agrees well with the experimental data. The π electron density, the dipole moment, and the bond order for the ground, singlet and triplet excited states have been obtained, and the characteristics of the electronic structures for the ground, singlet-excited, and triplet-excited states have been discussed in connection with the chemical behavior of the molecule.
Studies of Liquid-Liquid Partition Systems. V. The Formation of Mixed Dimers with Two Carboxylic Acids in Carbon TetrachlorideSekine, Tatsuya; Isayama, Muneo; Yamaguchi, Sumiko; Moriya, Hiromitu
doi: 10.1246/bcsj.40.27pmid: N/A
The distribution of acetic, propionic and butyric acids, or of mixtures of two of these acids, between carbon tetrachloride and aqueous solutions has been studied at 25°C. The distribution data have been explained in terms of the partition of the acid monomer molecules and the dimerization of the monomer molecules in the organic phase. A salting-out effect has been observed upon additions of sodium perchlorate to the aqueous phase; this salting-out effect is larger in the order butyric>propionic>acetic acid. From the distribution data, the equilibrium constants for the distribution and the dimerization have been determined, and the formation constants for the mixed-dimer molecules have been compared with the statistical values. It has been concluded that the mixed-dimer molecules are equally stable or only a little less stable than had been statistically expected.
The Surface Activity of Tetrabutylammonium Halides in the Aqueous SolutionsTamaki, Kunio
doi: 10.1246/bcsj.40.38pmid: N/A
The surface activity of the tetrabutylammonium halides at the air/aqueous solution interface or at the hexane/aqueous solution interface has been studied. The surface or inter facial tension versus the concentration curves of the electrolytes are markedly dependent on the kind of their counter-ions, just as with these electrolytes in aqueous solutions. The surface activity of tetrabutylammonium iodide is fairly strong; it approximately corresponds to that of the surface-active straight-chain electrolyte with an octyl group. From the thermodynamic parameters of the adsorption of tetrabutylammonium iodide, it is found that the standard free energy of adsorption becomes negative as a result of the large positive values of the standard entropy of adsorption, irrespective of the positive values of the standard enthalpy change. This suggests that the adsorption is a “hydrophobic” effect; that is, the “icebergs” around the nonpolar groups of the electrolyte return to the original water by the process of the transfer of the hydrophobic ions from the aqueous solution to the surface phase.
The Acid Strength and the Catalytic Activity of Solid Catalysts in the Oligomerization of PropyleneMisono, Makoto; Yoneda, Yukio
doi: 10.1246/bcsj.40.42pmid: N/A
The reaction activities and the reaction products of the oligomerization of propylene on several acidic solid catalysts, e. g., silica-alumina, sodium-exchanged silica-alumina and some other acidic catalysts, have been investigated in a circulation system in the range of 130–300°C and 100–600 mmHg. The acid strength and the acid contents of catalysts were qualitatively measured by amine titration, using several indicators, over the range from 1.5 to −12.8 in H0 function. Correlations between the reaction activity of the oligomerization of propylene and the acid strength as well as the acid content of the catalysts were demonstrated. The activation energies, the pressure dependency of the rate, and the reaction products were correlated with the acid strength as well. The high activity of some catalysts due to very strong acid sites was deactivated by coke formation in the initial stage of the reaction process. On the basis of an analysis of the reaction products, the major reaction at the stationary stage was ascertained to be the trimerization of propylene, which seemed to occur on moderately strong acid sites. The acid types responsible for the activity were discussed by the aid of “added back water.”