Showing papers in "Bulletin of the Chemical Society of Japan in 1968"

Calorimetric Study of the Glassy State. IV. Heat Capacities of Glassy Water and Cubic Ice

Abstract: By making use of the vapor-condensation type calorimeter, the heat capacity measurements of amorphous, cubic and hexagonal ices were made between 20°K and 250°K. The glass transition phenomenon was found near 135°K with the sudden change of the heat capacity amounting to 35 J/(mol°K). The drastic crystallization with the exothermic effect which amounts to 1.64 kJ/mol was then followed at this temperature. The transformation of the cubic crystal to the hexagonal one was confirmed to occur in the temperature region from 160 to 210°K and to proceed in two steps with the activation energies of 21.3 and 44.7 kJ/mol, respectively. The amount of the exothermic effect accompanying this transformation was found to be about 160 J/mol.

Phase Changes in Crystalline and Glassy-Crystalline Cyclohexanol

Abstract: It has been known that cyclohexanol has low-temperature form (crystal-II) and high-temperature form (crystal-I) and that the supercooled crystal-I shows in its heat capacity curve an anomalous jump resembled to that associated with glass transition. In order to clarify whether this anomaly arises from relaxation phenomenon or not, we have reinvestigated the heat capacity of this substance from 14°K to 320°K and obtained the values of 8827 J/mol, 265.31°K, 1782 J/mol and 299.09°K for heat of transition, transition point, heat of fusion and melting point respectively. Comparing the ideal gas entropy of cyclohexanol calculated from thermal data and that from statisticalmechanical data, we have estimated that the residual entropy of the crystal-II is of zero and that the potential barrier of internal rotation of OH group is 7.0 kj/mol. From these results, the residual entropy of the supercooled crystal-I amounts to 4.72 J/(mol deg K). We have discussed the glass transition of this crystal and proposed a new t...

On the Structures of Alkali Polyaluminates

Abstract: Besides the so-called β-Al2O3 (R2O·11Al2O3; R=Na or K), there have been found two kindred compounds with approximate formulas, R2O·7Al2O3 (β′-Al2O3) and R2O·5Al2O3(β″-Al2O3). The structure determination of the latter two compounds was undertaken; the results are compared with the structure of β-Al2O3 in the present paper. These three structures are composed of spinel layers of the same configuration. The structures of β and β′ are very similar to each other, both equally bearing a layer-stacking according to a two-fold screw symmetry, while β″ differs from these two in exhibiting another way of layer-stacking, according to a three-fold screw symmetry.

A Measure of the Electron-donating Power and Electron-accepting Power of Liquid Organic Compounds

Abstract: A quantitative study has been made of the measurement of the electron-donating nature and the electron-accepting nature of various liquid organic compounds. The position of the O–D or C=O absorption band of a liquid compound which contained a small quantity of methanol-d or of acetophenone was measured by means of an infrared spectrophotometer. The relative magnitude of the electron-donating nature or of the electron-accepting nature of the compound was compared by a measurement of the perturbation which it produced on the O–D vibrational band of methanol-d or on the C=O vibrational band of acetophenone. The electron-donating power or the electron-accepting power of a compound is defined as the relative difference (counted as wave numbers) of the O–D or the C=O absorption band observed in the compound from that in benzene. From the results, it was found that, in a homologous series, the electron-donating power decreased with an increase in the ionization potential in the gaseous phase, or with an increase...

The Dimerization of Butadiene by Palladium Complex Catalysts

Abstract: It has been found that palladium-phosphine complexes coordinated by dienophile and tetrakis-(triphenylphosphine) palladium catalyzed the linear dimerization of butadiene. The dimerization of butadiene with bis(triphenylphosphine)(maleic anhydride)palladium in aprotic solvents, such as benzene, tetrahydrofuran, and acetone, gave octatriene-1,3,7 selectively in good yields. In such alcohols as methanol, ethanol, and isopropanol, butadiene was converted to 1-alkoxyoctadiene-2,7 and/or octatriene-1,3,7, depending on the nature of the alcohols employed. The dimerization in secondary amines, such as morpholine, piperidine, and diisopropylamine, gave butadiene dimer-amine adducts of the R2N(C8H13) type, while that in primary amines, such as aniline and n-butylamine, gave a mixture of RNH(C8H13) and RN(C8H13)2. Phenoxy- and acetoxyoctadiene were also obtained from the reactions in phenol and acetic acid respectively.

Oxygen Oxidation of Ferrous Ions Induced by Chelation

Abstract: The oxidation of ferrous ions by dissolved oxygen in aqueous solutions in the presence of such chelating agents as EDTA, DTPA, EDTAOH, EDTP, CyDTA and NTA was studied spectrophotometrically. The rate equation for the oxidation reaction is:d[Fe^III]/dt=4k_p[Fe^IIHZ][O_2]+4k_n[Fe^IIZ][O_2] where kp is the rate constant for the (1) reaction; kn, the rate constant for the (2) reaction; FeIIHZ, protonated chelate, and FeIIZ, the normal chelate.&Fe^IIHZ+O_2\xrightarrowk_pFe^IIIZ+HO_2 \labeleq1&Fe^IIZ+O_2\xrightarrowk_nFe^IIIZ+O_2^-\labeleq2The linear relationship between log k and log Rf shown by Eq. (3), was obtained from all the experimental results except for those on the EDTPA and CyDTA systems:logk=0.92+0.13logR_f\labeleq3In Eq. (3), k is 4kp and Rf is KFeIIIL⁄KFeIIHL, for the protonated chelate, while k is 4kn and Rf is KFeIIIL⁄KFeIIL for the normal chelate. In the cases of the DTPA and CyDTA systems, a deviation from the straight line was observed. This can be explained by steric hindrance of the oxygen ...

Synthetic Inorganic Ion-exchange Materials. X. Preparation and Properties of So-called Antimonic(V) Acid

Abstract: The preparation of so-called antimonic acid under various experimental conditions has been investigated in order to establish its usefulness as a chemically-stable cation-exchange material. In this experiment, the antimonic acid was mainly obtained by the hydrolysis of antimony pentachloride, and was rarely obtained from metallic antimony or potassium pyroantimonate. The hydrolyzed precipitate was amorphous at first, but it was gradually transformed into crystalline powder by keeping it in the mother liquor for a long time. The crystallization of the amorphous precipitate was facilitated by raising the temperature within a range of 0–80°C, and by increasing the concentration of strong mineral acid on aging, regardless of the kinds of starting antimony substances. The water-content of the air-dried samples is decreased by increasing the period of aging; the composition of the sample approximates Sb2O5·4H2O. The crystal of the antimonic acid is cubic and belong to the space group Oh7(Fd3m), with a lattice c...

Calorimetric Study of the Glassy State. III. Novel Type Calorimeter for Study of Glassy State and Heat Capacity of Glassy Methanol

Abstract: An adiabatic Nernst-Type calorimeter with a cell for condensing a sample vapor as an amorphous state was constructed. By making use of this calorimeter, the heat capacities of the glassy, supercooled liquid, and crystalline states of methanol were measured from 20°K to 120°K. It was found that the state of methanol deposited on the chilled substrate at about 95°K from its vapor state shows a glass transition phenomenon at about 103°K accompanied with the sudden increase of heat capacity, ΔCP, amounting to 26 J/(mol°K). The drastic crystallization with the exothermic effect coming to 1.54 kJ/mol was observed near 105°K. The residual entropy for the glassy methanol was found to be 7.07 J/(mol°K). Based on these results it seems very plausible to propose that any non-crystalline solid deposited on the chilled substrate from the vapor state will show the glass transition phenomenon.

Desorbability of Chemisorbed Water on Metal Oxide Surfaces. I. Desorption Temperature of Chemisorbed Water on Hematite, Rutile and Zinc Oxide

Abstract: The desorbability of water molecules chemisorbed on the surfaces of metal oxides has been investigated in the cases of α-Fe2O3, TiO2 (rutile) and ZnO. Water vapor adsorption isotherms were determined on the samples treated at various temperatures in a vacuum of 10−5 Torr. The BET Vm-values of water adsorption were plotted against the temperature of the pretreatment. The curves obtained show a sharp increase at a moderate temperature which is varied by the nature of solid substance. This fact makes us conclude that, at this temperature, the chemisorbed water on oxide surfaces starts to be removed. The variation in the desorption temperature due to the nature of metal oxide is considered to come from the magnitudes of the bonding force of the surface hydroxyl groups to the surface metal atoms on each solid.

Spectroscopic Studies of Catalysis by Vanadium Pentoxide

Abstract: The role of the V=O bond in V2O5 in the adsorption of several gases was studied by measuring the electron spin resonance (ESR) and the infrared (IR) spectra. The ESR spectra of V2O5 supported on γ-Al2O3 were similar to those of VOSO4 on γ-Al2O3. When such electron-donating gases as CO, SO2 and C2H4 were adsorbed on this V2O5-γ-Al2O3, the signal intensity of ESR increased and the splitting of the h.f.s. became clear. Upon treatment with an electron-accepting gas such as O2, a reverse change was observed. In the case of V2O5 supported on SiO2, similar ESR spectra were observed by the adsorption of CO after a mild reduction. The IR spectra of V2O5 have a sharp absorption peak at 1023 cm−1 due to the stretching vibration of the (V=O)3+ bond; this peak became broader by adsorption of such gases as CO and SO2. Simultaneously, the center of the peak shifted to the red region and a weak hump appeared at 980–990 cm−1, probably due to (V=O)2+. These results of the ESR and IR measurements reveal that these electron-...

Intrachain Force Field and Normal Vibrations of Polyethylene Glycol

Abstract: Normal vibrations of polyethylene glycol and the perdeuterated species were treated. Intrachain force field was expressed in terms of local-symmetry coordinates. Force constants were adjusted by the method of least squares, with reference to observed infrared and Raman frequencies. A set of force constants was obtained, which reproduces the observed frequencies with an r. m. s. deviation of 0.9%. The values of the force constants thus refined were discussed in comparison with corresponding values of related molecules. Vibrational assignments of the observed infrared absorption bands and Raman lines were revised on the basis of potential-energy distributions refined in the present treatment.

The Analysis of the Solubility of Hydrocarbons in Water

Abstract: Enthalpy and entropy of solution of non-polar solutes in water diverge strikingly from the normal behavior established for regular solutions. This abnormality has been considered mostly due to the iceberg formation around solute molecules in water. The abnormal solubility and enthalpy and entropy of solution of non-polar solutes in water have been explained coherently by the extension of the regular solution theory, taking into account the iceberg formation of water molecules. Unlike currently accepted views on the hydrophobic bonding, it is concluded that the enthalpy of mixing (interchange) of non-polar solute with water is large, but the enthalpy decrease due to the iceberg formation of water largely cancels the enthalpy increase of mixing (interchange). Thus, the apparent enthalpy of solution is small or negative at low temperature. It is concluded that 1) the small solubility of non-polar solutes in, water is not an entropy effect, and 2) the solubility of non-polar solutes is promoted by the iceberg...

Photochemistry of Acetanilide. I. Quantum Yields of the Rearrangement and Benzene Photosensitized Reaction

Abstract: The photochemical rearrangement of acetanilide under 2537 A irradiation has been studied by spectrophotometry. The quantum yield of the rearrangement in cyclohexane solution was independent of the irradiation time, concentration of acetanilide, presence of oxygen and light intensity. It was found that electronic energy transfer from the electronically excited benzene to acetanilide occurred in the mixed solution, and the transfer mechanism was explained by singlet-singlet nonradiative energy transfer. It was observed that the energy transfer rate constant was about 22 times greater than that predicted by diffusion theory (the transfer rate constant, k3=1.45×1011 l·mol−1·sec−1). From these studies, it is proposed that the rearrangement of acetanilide is an introamolecular reaction and does not occur from the triplet state but from the lowest singlet excited state.

Nuclear Magnetic Double-resonance Study of the Hindered Internal Rotation in Formamide

Abstract: The nitrogen-14 quadrupole relaxation broadening effect on the proton spectrum of formamide was eliminated by a 1H–{14N} double resonance technique. The completely-decoupled proton spectra of formamide in the neat liquid and in acetone, dioxane, and water solutions were observed at several temperatures. The spectra observed at room temperature were analyzed on the basis of an ABC system, while the spectra at higher temperatures (∼100°C) were analyzed on the basis of an AB2 system. From the changes in the resonance lines of the formyl proton with the temperature, the values of the activation energy for the hindered internal rotation about the C–N bond, Earot, and for the intermolecular proton exchange involving the amine protons, Eaex, were obtained. It has been found that the hydrogen-bond formation on the carbonyl oxygen of formamide increases the Earot value and the magnitude of the vicinal coupling constants, while it decreases the magnitude of the geminal coupling constant.

Spectroscopic Studies of Mixed Amine Carbonyl Complexes of d6 Structure. II. Solvent Effect on the Ultraviolet and Visible Absorption Spectra of Diamine-tetracarbonyl Complexes of Chromium(0), Molybdenum(0) and Tungsten(0)

Abstract: Absorption bands, especially metal to amine charge transfer bands of bipyridyl- and phenanthroline-tetracarbonyl chromium (0), molybdenum (0) and tungsten (0) are shifted in various solvents by less than 4500 cm−1. The shift is discussed in accordance with McRae’s equation, which was derived with the point-dipole approximation. The solvents can be classified into two groups, the alcohol and the ester group. When three constants corresponding to (1) the interaction between induced dipoles of the solute and of the solvent, (2) the interaction between permanent dipole of the solute and induced dipole of the solvent, and (3) the interaction between permanent dipoles of the solute and of the solvent, are duely chosen for the two groups of solvent individually, the experimental values are satisfactorily accounted for. Short range interactions, such as hydrogen bonding can be ignored.

Phase Changes in the ZrO2-TiO2 System

Abstract: The liquidus curve in the ZrO2-TiO2 system previously reported by the present authors was again examined with a heliostat-type solar furnace in order to determine the peritectic point in the ZrO2-rich side region. Quenched specimens from the melt of the ZrO2-rich side region were analysed by the X-ray technique. The cooling curves from the melt suggested the existence of a new phase stable at higher temperatures, and a tentative phase diagram at high temperatures is presented.

Polarographic Behavior of Tris(2,2′-bipyridine)cobalt(II) and Tris(2,2′-bipyridine)cobalt(III) in Acetonitrile Solutions

Abstract: The electrode processes of tris(2,2′-bipyridine)cobalt(II) and tris(2,2′-bipyridine)cobalt(III) complexes at the dropping mercury electrode in acetonitrile solutions have been investigated by the measurement of direct current, alternating current and Kalousek polarograms. The cobalt(II) complex gave a one-step oxidation and a four-step reduction wave and the cobalt (III) complex, a five-step reduction wave, when tetraethylammonium perchlorate was used as supporting electrolyte. The solution containing the cobalt(II) and the cobalt(III) complexes gave a reversible composite wave. The limiting currents of the first two steps named from positive to negative potentials of the reduction wave of the cobalt(II) complex were diffusion-controlled, the first step being of a one-electron reduction process and the second step, of a two-electron reduction process. From the effect of free 2,2′-bipyridine and water on the reduction wave of the cobalt(II) complex and from the Kalousek polarograms, the electrode processes...

Effect of Pressure on Graphitization of Carbon. IV. Abrupt Graphitization of Hard Carbon under 5 kbar

Abstract: A hard carbon, phenolformaldehyde resin char carbonized to 700°C, was heat-treated under a quasi-hydrostatic pressure of 5 kbar at various temperatures between 1100–1800°C for the residence times of 3, 20 and 60 min. The graphitization process of the hard carbon under pressure consisted of three stages. In the first stage of the graphitization, the profile of (002) diffraction line was symmetrical. It means that there is only one component AH in the sample. In the second and third stages of graphitization, the (002) profile became composite. In the second stage, three components AH, G′H and G″H coexisted in the sample. The sum of the contents of the components G′H and G″H was less than 20% and increased gradually with heat treatment temperature. In the third stage, two components AH and G″H coexisted. The content of the component G″H increased abruptly up to more than 70% at about 1400, 1500 and 1700°C for the residence time of 60, 20 and 3 min, respectively. The components AH and G″H have the turbostrati...

γ-Radiolysis of a Binary Mixture of Methanol and Water. The Formation of Formaldehyde in the Radiolysis of Liquid Methanol

Abstract: The γ radiolysis of a binary mixture of methanol and water over a wide concentration range has been investigated. The observed yields of products are expressed as a linear function of the electron fraction of methanol in the mixture. The yields of molecular hydrogen were also determined. Analyzing the results on reasonable assumptions, one could obtain for neutral water, Ge\barsw=2.3–2.5 and GOHw≥2.6. It was concluded that, in the radiolysis of methanol, formaldehyde may be produced through the decomposition of CH2OH radicals in the spur region, not by the disproportionation of these radicals.

Electronic Absorption and Emission Spectra of 9, 10-Dichloroanthracene and 9, 10-Dibromoanthracene Crystals

Abstract: The electronic absorption spectra of three crystalline modifications of anthracene derivatives have been measured; they are the α and β form of 9, 10-dichloroanthracene and 9, 10-dibromo-anthracene. The assignment has been presented for each absorption band. The charge transfer absorption which is regarded to the transition between two stacked molecules has been observed in the α-form of 9, 10-dichloroanthracene; also a Rydberg type transition which has an out of plane polarization is found in this crystal starting at 290 mμ. It is unusually broad and is regarded as a band to band transition. The emission band has been measured at different temperature; it is found that excimer type emission is most prominent in the β-form of 9, 10-dichloroanthracene, in which intermolecular approach in the excited state will occur with less difficulty. A criterion for strong, medium, and weak interactions in the excited state is presented by comparing the shift, and the shape of the emission band with the intermolecular ...

The Structure of Meisenheimer Complex as Determined by X-ray Crystal Analysis

Abstract: The structure of the Meisenheimer complex has been determined by the X-ray method. The complex is characterized by a symmetrical structure, in which the two methoxyl groups are nearly equivalent to each other. The results showed a peculiar shape of the reaction intermediate, the substituted carbon atom is transformed into a tetrahedral shape, while the planarity of the whole molecule is kept with an increased conjugation between the nitro group and the ring system.

The Cyclization of Malononitrile and Ketones by Ammonium Acetate

Abstract: Hitherto various heterocyclic compounds have been synthesized by the reaction of ketones with ethyl cyanoacetate or ethyl acetoacetate in the presence of excessive ammonium acetate. On the basis of these facts, the reaction of malononitrile with ketones by ammonium acetate was carried out; aminopyridine derivatives, such as 2, 4-diamino-3, 5-dicyano-6-alkylpyridines (I) and 2-amino-3-cyano-4, 6-dialkylpyridines (II), were thus obtained.