Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 44 , Issue 5
Showing 1-50 articles out of 82 articles from the selected issue
  • Haruo Takaya, Naoyuki Todo, Tadasuke Hosoya, Toshio Minegishi
    1971 Volume 44 Issue 5 Pages 1175-1178
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    In order to confirm whether a water molecule (or molecules) is held in a protonated activated complex by electrostatic interaction or by a partial valence bond, the pressure dependency of the activation volume, ΔV\ ewq, for the hydration of propylene was measured at 180°C. The pressure effect on the rate of the hydration of propylene was studied in such dilute sulfuric acid solutions of a 0.0000108 mole fraction (0.00060N under S.T.P.) that the dielectric constant, D, and the density of pure water could be replaced for those of the reacting solution. The absolute value of the ΔV\ ewq decreases steeply from 19 ml/mol at 300 kg/cm2 to 4 ml/mol at 5000 kg/cm2. The activation energies and entropies, obtained from the temperature dependency of the reaction rate, are 22.7 kcal/mol and −16.6 e.u./mol respectively at 1000 kg/cm2 and 21.9 kcal/mol and −17.0 e.u./mol respectively at 3000 kg/cm2. The ΔV\ ewq is approximately proportional to the −∂DD2p value, (D: dielectric constant of medium; p: pressure), which follows from the Krichevski equation; hence, it was concluded that the contraction of water around an activated complex by electrostatic interaction contributes to the ΔV\ ewq and that a water molecule (or molecules) is held in the activated complex by electrostatic interaction. The case of a water molecule being held by a partial valence bond was discussed in terms of the molar volumes of the reactants.
  • Haruo Takaya, Naoyuki Todo, Tadasuke Hosoya, Toshio Minegishi
    1971 Volume 44 Issue 5 Pages 1179-1182
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The nature of a bond between a water molecule and a protonated propylene in the activated complex for the acid-catalyzed hydration of propylene was discussed. The number of water molecules contained in the activated complex, 1.3, was obtained by applying the acidity function, T0, to the dependency of the logk1 on the acid concentration for the hydration of various olefins. The general relationship between the electrostriction and the hydration number of various uni-valent cations was also discussed, and these ions were divided into two separate groups. In the first group, the hydration was caused by electrostatic interaction, while in the second group, the hydration was caused mainly by covalent bond formation. Since the representative point of the hydration of propylene was located near the first group, it was concluded that a molecule of water is held in the activated complex by electrostatic interaction. On the basis of these considerations, the present authors propose a hypothesis which is useful in characterizing the nature of a bond between a water molecule and a protonated substrate in an activated state: (a) If the logk1 for a reaction increases linearly with –H0, a water molecule (or molecules) is held in an activated complex by electrostatic interaction. (b) If the logk1 for a reaction increases linearly with the logma, a water molecule is held in an activated complex by the formation of a covalent bond. k1: the first order rate constant; H0: Hammett’s acidity function; ma: acid concentration.
  • Katsutoshi Ohkubo, Tokio Yamabe
    1971 Volume 44 Issue 5 Pages 1183-1187
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The interaction between sulfonium salts and molecular oxygen was studied by the ASMO SCF method. Firstly, the results of the ASMO SCF calculation of trimethylsulfonium chloride suggested that the bond between the sulfonium cation and the anion was constituted mainly of the bonding (d-p)π-type overlaps (made by 3dyz-(or 3dxz-) of S and 3py (or 3px) of Cl) and of the antibonding (d-p)σ-type overlaps (made by 3dz2 (or 3pz) of S and 3pz (or 3dz2) of Cl). Secondly, the sulfonium salt interacts with molecular oxygen mainly through a (d-p)σ-type overlap between the 3dyz-(or 3dxz-)orbital of the former and the (1πg)z-orbital of the latter. Thirdly, a maximum overlap formed between 3d-sulfur orbitals and 1πg-orbitals of O2 is established at the O2-rotation angle of π/4 to the direction of the d-orbital expansion. Finally, the change in the energy state of O2 caused by the sulfonium-salt interaction was discussed.
  • Katsutoshi Ohkubo, Hidetoshi Shimada, Yasuhiro Shiotani, Masahide Okad ...
    1971 Volume 44 Issue 5 Pages 1188-1193
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    A theoretical consideration of the catalytic activity of group I metal salts, especially of lithium ones, for the homogeneous liquid-phase oxidation of hydrocarbons was developed by extended Hückel molecular orbital calculations, with particular reference to the interaction between the salts and molecular oxygen. We made several findings. First, a marked activity of lithium salt-catalysts was reflected by a remarkable “electron-partial occupation” of the lithium cation in their salts. Second, a strong interaction of the lithium catalyst with O2 occurred at the angle of 15° to the direction of the 1πg-orbital expansions of O2. Third, the lithium catalyst participated strongly in the activation of O2 at the distance of 2 Å–3 Å, increasing the electron-population of one oxygen atom located farther from the lithium cation. Finally, the contribution of the “activated” oxygen molecule to the initiation of the oxidation of hydrocarbons was discussed.
  • Tsunetake Fujiyama
    1971 Volume 44 Issue 5 Pages 1194-1200
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Deformation vibrations associated with displacements of skeletal heavy atoms are mainly discussed. It is shown that skeletal deformation vibrations are sensitive to the change of an azimuthal angle θ and that the frequencies of the vibrations are specific for the structure of rotational isomers. The θ-dependency of skeletal deformation vibrations corresponds exactly to that of elements of a kinetic energy matrix \barG. The results emphasize the simplicity and the usefulness of the approximate normal coordinate treatment in which only skeletal heavy atoms are taken into account.
  • Kazuyoshi Sakamoto, Yasumasa J. I’Haya
    1971 Volume 44 Issue 5 Pages 1201-1205
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The extended Hückel (EH) method with different basis functions and the variable electronegativity extended Hückel (VEEH) method are applied first to the calculation of the electronic structure of CO and then to that of three oxocarbon anions, (C4O4)2−, (C5O5)2−, and (C6O6)2−. MO energies of CO calculated by both methods are closer to those computed by a non-empirical SCF method and also to observed values, compared with those obtained by the CNDO/1 method. It is also found for CO and the three anions that in the EH method the charge distributions are not dependent on the basis functions chosen and are much more localized on the oxygen atoms than in the VEEH method. The latter method yields a π-electron distribution which is close to that predicted by the variable electronegativity π-electron SCF method. The EH and VEEH methods predict reasonable values for the lower excitation energies of these oxocarbon anions; specifically the calculated σ→π* excitation energy of (C4O4)2− agrees well with an observed value.
  • Hajime Ishii, Motohiko Koyanagi, Yoshiya Kanda
    1971 Volume 44 Issue 5 Pages 1205-1212
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Emission spectra of pyrazine and its deuterated derivatives have been observed in the vapor and the vibronic structure has been analyzed in detail. The vibronic structures of the phosphorescence spectra of these compounds have been explained all in terms of totally symmetrical vibrations, while the first main bands of the fluorescence spectra were anomalous as well as their progression bands in respect to the band position and intensity distribution. For comparison, the fluorescence spectra have also been studied in rigid matrices at 90°K.
  • Hiroyuki Horiguchi, Soji Tsuchiya
    1971 Volume 44 Issue 5 Pages 1213-1218
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The concentrations of Hg(63P1) and (63P0) atoms, [Hg1*] and [Hg0*], were determined from the absorptions of 4358 and 4047 Å lines in the Ar-diluted mercury vapor in the presence of several quenching molecules, under the radiation of 2537 Å emission. An apparent absorption intensity was not proportional to [Hg1*] or [Hg0*], and was sensitive to the ratio of the spectral half-width of the light source to that of the absorption line. Therefore, a method to correct an absorption intensity was proposed. The relation of [Hg1*] to [Q], a concentration of quenching molecules, is explained well by the Stern-Volmer equation. The value of [Hg0*] increases with [Q] until it reaches a maximum at a certain value of [Q], and a further increase of [Q] results in a decrease of [Hg0*]. These findings are explained well by the following mechanism: (1) Hg+hν→Hg1*, (2) Hg1*→Hg+hν, (3) Hg1*+Q→Hg+Q, (4) Hg1*+Q→Hg0*+Q, (5) Hg0*+Q→Hg+Q, (6) Hg0*→Hg (by collisions with a wall). The respective values of cross-sections (σ2) of N2, CO, and NO for process (3) are ≤0.03, 0.60, and 20 Å2, and those for process (4) are 0.36, 2.1 and 5 Å2, and those for process (5) are ≤3.6×10−4, 0.15 and 8.0 Å2.
  • Tsutomu Kagiya, Y\={u}z\={o} Sumida, Toshihiro Tachi
    1971 Volume 44 Issue 5 Pages 1219-1223
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The preferential adsorption equilibria of various binary solutions of cyclohexane-aromatic compounds and cyclohexane-cyclic ethers on chromatographic silica gel have been studied at 30°C. On the basis of the assumption that the adsorption is of the Langmuir-type, the separation factors (α) and the numbers of moles in the adsorbed-phase per unit mass of silica gel (nσm) have been calculated. The values of logα correlate well not only with the electron-donating properties of the preferentially-adsorbed components, but also with the powers of the gas-phase adsorption on silica gel and of the liquid-liquid interaction with liquid trimethylsilanol. Moreover, on the basis of the information on nσm, the orientation angles of the adsorbed components on the surface have been evaluated. The adsorption of the aromatic hydrocarbons was nearly flat to the surface, and that of the cyclic ethers, perpendicular.
  • Osamu Kiyohara, Kiyoshi Arakawa
    1971 Volume 44 Issue 5 Pages 1224-1230
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Sound velocity and density of binary mixtures of t-butyl chloride (tBC), t-butyl bromide (tBB), and 1,1,1-trichloroethane (TCE) with carbon tetrachloride (CT), benzene (B), and p-xylene (pX) were measured at temperatures, 25 and 35°C. The excess molar volume and excess compressibility of these systems were calculated. The temperature dependency of excess volume was negative for aromatic solutions and positive for CT solutions. The temperature coefficients of excess compressibility were negative for all systems. The relation between thermodynamic properties and intermolecular interactions in these systems were discussed. Two systems, B-TCE and CT-TCE, were found to be nearly ideal. The solute-solvent interactions in CT-tBC and tBC-TCE systems were found to be more attractive than in other systems.
  • Siro Nagai, Shun-ichi Ohnishi, Isamu Nitta
    1971 Volume 44 Issue 5 Pages 1230-1233
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Benzene, toluene, o-, m-, p-xylene, and mesitylene adsorbed on silica gel were γ-irradiated at −196°C. ESR spectra observed at −196°C for these systems at low contents of the methylbenzenes were assigned to the respective monomer cations. Dimer cations of benzene, toluene, and p-xylene were produced on γ-irradiation at −196°C of the adsorbed systems at higher contents and also by the reaction of monomer cations and neutral molecules at higher temperature than −160°C.
  • Teruo Nomura, Masayoshi Nakahara
    1971 Volume 44 Issue 5 Pages 1233-1238
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The structure of NH4[Co(So3)2(NH3)4]·3H2O has been determined by the heavy-atom method and refined to R=0.12 by a least-squares analysis based on 874 three-dimensional visual data. The compound crystallizes in the orthorhombic space group P212121 with unit cell dimensions of a=10.995, b=17.563, c=6.834 Å, and Z=4. The two sulfito groups in the complex anion are coordinated to the central cobalt atom in cis positions through their sulfur atoms, with Co-S distances of 2.23 Å (mean). The cis-configuration of brown sodium salt, with an absorption spectrum similar to that of the trihydrate of ammonium salt, has also been established.
  • Keiji Kawamoto, Atsushi Tatani, Toshinobu Imanaka, Shiichiro Teranishi
    1971 Volume 44 Issue 5 Pages 1239-1243
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The codimerization of styrene with vinyl compounds catalyzed by di-μ-chloro-dichlorobis(styrene)dipalladium(II), (Pd(C6H5CH=CH2)Cl2)2, was investigated in a homogeneous system under mild conditions. The reaction of styrene and methyl acrylate carried out at 50°C for 6 hr yielded 220% codimers, 169% dimers of methyl acrylate, and 18% dimers of styrene, on the basis of the palladium(II) used. The codimerizations of styrene with vinyl acetate and with methyl vinyl ketone gave 50% codimer and 125% codimers respectively. When nitroethylene and n-butyl vinyl ether were used as the vinyl compound, no codimers were formed. The codimerization of styrene-d3 with ethylene was also carried out. The reaction mechanism involving the five-coordinate hydridopalladiumolefin intermediate was proposed and discussed in the terms of the distribution of deuterium in the codimer of styrene-d3 and ethylene, the functional group effects of vinyl compounds, and solvent effects on the codimerization.
  • Kinsi Motomura, K\={o}j\={u} Sekita, Ryohei Matuura
    1971 Volume 44 Issue 5 Pages 1243-1248
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Average properties of a copolymeric chain in which a segments of the kind A and b segments of the kind B occur alternatively are calculated for an infinite chain length. For the simplest case of a=b=1, i.e. an alternating copolymeric chain (–A–B–)N, the average number of adsorbed segments of A, \barνA, that of B, \barνB and the mean square end-to-end distance \barr2 are computed numerically as functions of the adsorption energies εA and εB. The values of \barνA, \barνB, and \barr2 are proportional to N for larger values of ηA (=exp(εAkT)) than the critical value (ηA)c at fixed ηB, as found for the case of a homogeneous polymeric chain. It is seen that the behavior of the copolymeric chain near an interface is affected distinctively by the adsorption energies of the segments A and B, and the copolymeric chain is forced to adsorb even for a fairly low adsorption energy of the segment of one kind if the adsorption energy of the segment of the other kind is sufficiently large.
  • Kinsi Motomura, Yoshikiyo Moroi, Ryohei Matuura
    1971 Volume 44 Issue 5 Pages 1248-1252
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    In order to develop further the theoretical treatment of a polymeric chain adsorbed at an interface, a random walk model, in which each step has the same probability except that no step can retrace the preceding one on a simple cubic lattice, has been used. The average number of adsorbed segments \barν, the average number of trains \barm, and the mean square end-to-end distance \barr2 are calculated as functions of the adsorption energy of segment ε and the number of segments n when n is infinitely large. The average numbers of segments in a train and a loop, \bark′ and \bark′, are also calculated. Through the increment in the value of critical adsorption energy εc, prohibition of immediate reversal for the random walk fairly influences the average properties of adsorbed polymeric ,chain. The decrease in \barm and the increase in \bark′ with ε⁄kT at its large values are remarkable in comparison with those of the symmetric random walk, which may be accounted for by the diminution of the chance of making loops. It is shown that \barr2 is equivalent to the mean square two-dimensional end-to-end distance of a restricted random walk without immediate reversals on a simple cubic lattice at εckT and approaches that on a simple square lattice in the limit ε⁄kT→∞.
  • Hiroshi Hosaka, Kenjiro Meguro
    1971 Volume 44 Issue 5 Pages 1252-1256
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The surface and bulk properties of silica-titania systems, prepared by the co-hydrolysis of silicon ethoxide and titanium tetrabutoxide, were investigated by measuring the heat of immersion, the adsorption of nitrogen, water, and ammonia, the X-ray diffraction, the DTA, and the TGA. It was found that the addition of silica to titania has a large suppressive effect on the crystal growth of anatase and on the transformation of anatase to rutile. The heat of immersion, the surface hydrophilicity (the surface area by water adsorption/the surface area by nitrogen adsorption) and the amount of ammonia adsorbed gave inverted sigmoid curves when the titania content was varied. Especially, the shape of the curve of the change in the heat of immersion coincides approximately with that of the surface hydrophilicity.
  • Katsumi Nakamaru, Shigeya Niizuma, Masao Koizumi
    1971 Volume 44 Issue 5 Pages 1256-1261
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    It was established that upon irradiation, the degassed ethanol solution of 9-chloroacridine is quickly converted into 9,9′-biacridyl by the reaction 2 (9-Cl-acridine) \overset+2H\underset(hν)→ 9,9′-biacridyl+2HCl and that 9,9′-biacridyl produced is then reduced photochemically to 9,9′-biacriden as the main product. The reaction scheme completely denies the scheme previously proposed (V. Zanker and W. Flügel, Z. Naturforsch., 19(b), 376 (1964)) in which the primary photoproduct is a charge transfer complex between 9-Cl-acridine and its reduced form. 9,9′-biacridyl is photoreduced to an acridan-like compound even in the aerated solution perhaps via molecular mechanism in contrast to 9-Cl-acridine which yields acridone under similar conditions. ESR spectrum with hfs was detected in the acidic solution (degassed) containing 9,9′-biacriden produced photochemically. The mechanism of its production was discussed. Similar reactions using various solvents (aerated and deaerated) were examined and the general feature of the primary processes was described.
  • Yoshio Sasada, Hirotaka Shimanouchi, Hachiro Nakanishi, Masaki Hasegaw ...
    1971 Volume 44 Issue 5 Pages 1262-1270
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    2,5-Distyrylpyrazine(C20H16N2), which has photo-polymerizability in the crystalline state, crystallizes in the orthorhombic system with cell dimensions of a=20.638, b=9.599, and c=7.655 Å, including four molecules in the unit cell. The space group is Pbca. The structure has been determined by the direct method and refined by the block-diagonal-matrix least-squares method using three-dimensional data. The molecules is not planar; the average plane of the pyrazine ring makes a dihedral angle of 12.09° with that of the benzene ring. The molecules are spaced by the c-translation forming an almost parallel plane-to-plane stack. In this stack, the ethylenic double bonds approach each other at the shortest intermolecular distances of 3.939 Å, since the long axis of the molecule makes an angle of about 30° with the c-axis. Therefore, the polymerization may occur between these double bonds to form a cyclobutane ring.
  • Yôichi Iida
    1971 Volume 44 Issue 5 Pages 1271-1273
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The spin-density distribution in the p-chloranil anion radical was determined by means of the difference in the bond orders of the conjugated systems between p-chloranil and its anion radical, which was estimated on the basis of the stretching force constants. It was found that the spin-density distribution calculated by this method was in good agreement with that estimated by means of the molecular orbital calculations or by means of the hyperfine splitting constants in the ESR absorption. In view of these results, it was suggested that the present method might become a new tool for investigating the unpaired electron distributions of ion-radical molecules in general.
  • Fusao Takusagawa, Ken Hirotsu, Akira Shimada
    1971 Volume 44 Issue 5 Pages 1274-1278
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The crystal structure of pyromellitic acid dihydrate has been determined by the method of X-ray diffraction. The crystal is triclinic in the P\bar1 space group, with Z=1 and cell dimensions of a=10.05, b=6.45, c=5.45 Å, α=74.5°, β=112.2°, and γ=77.3°. The structure was derived from the three-dimensional Patterson function and was later refined by the least-squares method, using the anisotropic thermal parameters, to give a final R index of 7.4%. All the hydrogen atoms were located on the difference-synthesis map. The average C(ring)–C(ring) distance is 1.386 Å, while the average C(ring)–C(carboxyl) distance is 1.496 Å. One carboxyl group is twisted by 17.9°, and the other is twisted by 74.5°, out of the plane of the benzene ring. The C–O(H) and C=O distances differ significantly from each other, the average values being 1.302 and 1.211 Å respectively. Four types of hydrogen bonds, with an average O–H···O distance of 2.732 Å, form a three-dimensional network. Thus, each molecule is joined, through hydrogen bonds around the center of symmetry, to two other molecules, forming an endless chain in the [1 \bar1 1] direction. Water molecules are arranged on the plane parallel to (1 1 0) so as to hold the chains together by hydrogen bonds.
  • Shukichi Sakuraba, Ryoka Matsushima
    1971 Volume 44 Issue 5 Pages 1278-1281
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    On the basis of the assumed mechanism for the photolysis of the uranyl-lactate system, the equilibrium constant for the complex formation, K, was evaluated from the photo-kinetic data by using a monochromatic 4047 Å light; it was then compared with those obtained from the usual spectrophotomeric measurements. A comparison of the K values obtained by means of the photo-kinetic data (1.0–1.1×10−1) and by means of the analytical data (1.1–1.2×10−1) gave an excellent agreement; there was also a good agreement between the slope of the plot of the photo-kinetic data and that predicted from the assumed mechanism. The results supported the crude mechanism assumed earlier.
  • Tetsuo Morimoto, Mahiko Nagao, Junichiro Imai
    1971 Volume 44 Issue 5 Pages 1282-1288
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The specific surface area, the water content, and the water adsorption isotherm have been measured in order to investigate the interaction between the surfaces of SiO2, Al2O3, and SiO2·Al2O3 and water molecules. Al2O3 gives II-type adsorption isotherms and the amount of adsorbed water on it increases with a rise in the temperature of pretreatment, whereas SiO2 gives isotherms approximate to the III-type and the amount of adsorbed water is larger when treated at lower temperatures. With SiO2·Al2O3, it was found that the type of isotherms and the effect of the pretreatment temperature are similar to those of Al2O3, and that the amount of adsorption increases with an increase in the Al2O3 content. By analysing the adsorption data, the ratio of the amount of physisorbed water in the first layer to the amount of the underlying chemisorbed water was calculated. As a result, it was found that the H2O:OH ratio is 1:2 on the surface of Al2O3, whereas it is 1:1 on the surface of SiO2. The analysis of the isotherms on SiO2·Al2O3 showed that the adsorption property of water on them is not additive: e.g., the amount of adsorbed water on SiO2·Al2O3 is larger than the sum of the water adsorbed on each component. Thus, it has been concluded that, on the surface of SiO2 in contact with Al2O3, the surface hydroxylation proceeds more rapidly than on the surface of pure SiO2.
  • Kenyu Kina, Kyoji Tôei
    1971 Volume 44 Issue 5 Pages 1289-1293
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The stability constants of copper(II) chelates with o-phenylenediamine derivatives have been determined by the pH titration method. The measurements have been carried out at 25.0±0.1°C and μ=0.10(by KNO3).
    o-Phenylenediamine derivatives, which have a substituent group (CH3, CH3O, COOH, or Cl, etc.) at the 4 positions, were used as ligands. The overall stability constants of the copper chelates are of the order: CH3, CH3O, H, COO, Cl, COOH; their values were 8.50, 8.42, 7.72, 7.06, 5.76, and 5.35 respectively. The effects of substituent groups on the stability constants have been studied. The plot of the overall stability constants against the sum of Hammett σm and σp values was found to be linear. The chelate stability and acid dissociation constants of the acido complexes of 3,4-diaminobenzoic acid were determined by the use of an augmented matrix.
  • Yoshimi Kurimura, Kousaburo Ohashi, Toshio Ohtsuki, Katsumi Yamamoto
    1971 Volume 44 Issue 5 Pages 1293-1296
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The kinetics of Fe2+ reductions of cis-α-Co(trien)Cl2+, cis-α-Co(trien)OH2Cl2+ and cis1-Co(trien)OH2Cl2+(trien=triethylenetetramine) have been studied at 25°C, [H+]=0.10 M and Σ[ClO4]=1.0 M. The second-order rate constants obtained are 4.0×10−4 M−1 sec−1, 1.6×10−4 M−1sec−1, and 9.8×10−5 M−1 sec−1 for cis-α-Co(trien)Cl+2, cis-α-Co(trien)OH2Cl2+, and cis1-Co(trien)OH2Cl2+ respectively. It is demonstrated, by comparing with other rate data for the Fe2+ reductions of cis-CoN4XCln+ (N=NH3, 0.5 en and 0.25 trien, and X=H2O and Cl) that the rate decreases with an increase in the number of chelate rings in the Co(III) complexes. The chelate effect of the nonbridging ligand on the electron-transfer reactions of Co(III) complexes is discussed on the basis of a model which involves the ligand-field strength of the trans-ligand to the bridging one, the energy needed for stretching the trans-group away from the Co(III) center, and the effect of the solvation.
  • Bunji Iwasaki, Takashi Katsura
    1971 Volume 44 Issue 5 Pages 1297-1301
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Oxygen partial pressure in equilibrium with nonstoichiometric ceric oxide of a definite composition were determined by equilibration with pure oxygen, air, CO2, and CO2-H2 mixtures at 900, 1000, 1100, 1227, and 1300°C, using a thermobalance. The values for the activities and the relative partial enthalpies and entropies of both Ce2O3 and CeO2 were calculated on the basis of the relation between the Po2 and its composition.
  • Terumasa Nakamura, Mitsuyasu Kimura, Hirohiko Waki, Shigeru Ohashi
    1971 Volume 44 Issue 5 Pages 1302-1305
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The anion-exchange distribution ratios of tri-, tetra-, and pentaphosphate were determined in a Dowex 1-X4-potassium chloride system at different pH by the batch method. The difference between the mean charges of the phosphates in resin phase and solution was explained in terms of a higher pH of resin phase than that of the solution. pH dependence of the separation factors for tri- and tetraphosphate and for tetra- and pentaphosphate was estimated from the batch equilibrium data, and the relative elution positions of these phosphates were confirmed by the practical chromatographic runs.
  • Toshiaki Mitsugashira
    1971 Volume 44 Issue 5 Pages 1305-1310
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Studies of the chemical behavior of protactinium(V) in a perchloric acid solution were carried out by the HDEHP-benzene extraction method. When the protactinium concentration was lower than 10−7 M, the extraction reaction was considered to proceed as:
    PaO(OH)2+aq.+ 3(HA)2 org.= PaOp(OH)qA5−2pq(HA)2p+q+1 org.+ 2H+aq.+ (2–pq)H2Oaq.
    where p=1, q=0 or 1, and p=2, q=0
    and
    Pa(OH)32+aq.+ 3(HA)2 org.= PaOp(OH)qA5−2pq(HA)2p+q+1 org.+ 2H+aq.+ (3–p-q)H2Oaq.
    where p=0, q=0, 1, 2, or 3; p=1, q=0 or 1 and p=2, q=0.
  • Yasuo Iwanami
    1971 Volume 44 Issue 5 Pages 1311-1313
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The reactions of dimethyl acetylenedicarboxylate (V) with p-chloroaniline, ethanolamine, ethylenediamine, o-aminophenol, and o-phenylenediamine gave dimethyl N-(p-chlorophenyl)aminofumarate(VI), 3-methoxycarbonylmethylene-3,4,5,6,-tetrahydro-2H-1,4-oxazin-2-one (VII), 3-methoxycarbonylmethylenepiperazin-2-one (VIII), 3-methoxycarbonylmethylene-3,4,-dihydro-2H-1,4-benzoxazine-2-one(IX), and 3-methoxycarbonylmethylene-3,4-dihydro-2(1H)-quinoxalinone(X), respectively. It has been shown that methoxycarbonylmethylene is a common structural element in all products, where the carbonyl is hydrogen-bonded with an amino group to form an enamine form. The spectra measured for crystals (IR) and for solutions in inert solvents (NMR) exhibited the fixation of the enamine form preferentially to the imine form, while NMR spectra for trifluoroacetic acid solutions indicated both forms in equilibrium. Tautomerization occurring in the acid is discussed.
  • Yasuo Iwanami
    1971 Volume 44 Issue 5 Pages 1314-1316
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Methyl and ethyl isoxanthopterin-6-acetates and their 4-amino analogues have been prepared via a new route from acetylenedicarboxylate and 2,5,6-triamino-4-hydroxypyrimidine or 2,4,5,6-tetraaminopyrimidine. These compounds uniquely exist in the imine form as evidenced by NMR and IR spectral data. This is the only exceptional case so far examined, since a number of related compounds exist in enamine form. When dissolved in sulfuric acid, however, tautomerization of imine to enamine is observed. It was demonstrated by NMR inspection that the methylene hydrogen on the side chain is exchangeable with deuterium. The tautomerism in sulfuric acid is discussed.
  • Yasuo Iwanami, Taketsugu Seki, Takeshi Inagaki
    1971 Volume 44 Issue 5 Pages 1316-1321
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Seven phenacyl derivatives of 2(1H)-quinoxalinone and 2H-1,4-benzoxazin-2-one (IV and V) have been synthesized to introduce a common structural element –CH2–CO– into their 3-positions. Their structures are compared with those of the related compounds described previously. The main purpose of the present study was to see whether or not their ring double bonds ((Remark: Graphics omitted.)) have ever been displaced onto the side chains, constituting an enamine so as to form =CH–CO–, the carbonyl of which is hydrogen bonded with the secondary amino group of the rings thereby formed. Consequently, existence as the enamine form, facilitated by an intramolecular hydrogen bonding, has been evidenced by IR and NMR spectral data. It is, therefore, fitting to call them by the more practical expression “3-phenacylidene-3,4-dihydro-2(1H)-quinoxalinone” (IVa), and so on. Hydrolysis of IV gave the corresponding 3-methyl-2-(1H)-quinoxalinones (VI) and benzoic acid (VII), while that of V afforded the starting substances, o-aminophenols (III) and benzoylpyruvic acid (VIII) which had been partially decomposed into pyruvic acid (IX) and VII.
  • Takayuki Ohta, Keisuke Ebina, Noboru Yamazaki
    1971 Volume 44 Issue 5 Pages 1321-1327
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The oligomerization of butadiene has been found during the electrolysis of solutions containing nickel(II) chloride and electron donors. The oligomerization was affected by the nature of the electron donors used. When the ethanolic solutions of tetrakis(pyridine)nickel(II) chloride or nickel(II) chloride and pyridine with tetra-n-butyl ammonium perchlorate or methanolic solutions without the perchlorate were electrolyzed in the presence of butadiene, a number of linear and dihydrogenated oligomers, with small amounts of branched oligomers, were obtained. The main oligomers were identified as n-octadiene, n-dodecatriene, and n-hexadecatetraene. By adding triphenylphosphine to the reaction system in place of pyridine, n-octatriene and alkoxyoctadiene were catalytically produced instead of hydrooligomers, accompanied by tetrakis(triphenylphosphine)nickel(0). A mechanism involving π-allyl intermediates was proposed for the oligomerization.
  • Hajime Watanabe, Jun Katsuhara, Noriyuki Yamamoto
    1971 Volume 44 Issue 5 Pages 1328-1329
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The rearrangement of (+)-cis- (I) and (−)-trans-pulegone oxide (II) was effected by the catalysis of zinc bromide in boiling benzene to give the same (−)-2,2,5-trimethylcyclohepta-1,3-dione (III), with a retention of the optical activity. The structure of (−)-III with the expanded 7-membered ring was confirmed by the chemical transformation into 1,1,4-trimethyl-cycloheptane(IV), which was identical with that derived from eucarvone(V). Piperitone oxide(VIII) was also converted into diosphenol(X) in the same manner as in pulegone oxides.
  • Yoshiharu Izumi, Kazuo Ohkubo
    1971 Volume 44 Issue 5 Pages 1330-1333
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The asymmetric activities of the catalysts modified with L-α-amino and L-α-hydroxy acids, which have two asymmetric centers on α, β and α, γ-carbons were studied, and the participation of the β- and γ-configurations to the asymmmetric activity of the catalyst was made clear. It was found that the S:β-configuration and the S:γ-configuration increase the asymmetric activity of the + and − directions respectively.
  • Fukuji Higashi, Toshio Ninomiya, Yoshiharu Izumi
    1971 Volume 44 Issue 5 Pages 1333-1336
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The effects of various additives in methyl acetoacetate were tested in the asymmetric hydrogenation reaction. Among them, water has a particular effect on the asymmetric activities of the catalysts; in the presence of a certain amount of water, the catalysts modified with L-Glu, L-Val, and L-Ala hydrogenated methyl acetoacetate to methyl Ls(+)3-hydroxybutyrate, while, without the addition of water, the catalysts promoted the hydrogenation to yield methyl Ds(−)3-hydroxybutyrate. The catalyst modified with L-Ala at pH 6.0 and the catalyst modified with L-Glu at pH 5.0 and 100°C were especially sensitive to water, and both catalysts showed (+) asymmetric activity when a trace of water was also present. Even in the hydrogenation without the addition of water, the recovered catalysts modified with L-Glu, L-Val, and L-Ala from the hydrogenation in the presence of water gave results similar to those in the hydrogenation in the presence of water. The effect of water as an additive was discussed, and it was concluded that the water affects the asymmetric site of the catalyst rather than the keto-enol equilibrium of the substrate.
  • Michinori Oki, Takashi Yoshida
    1971 Volume 44 Issue 5 Pages 1336-1338
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The infrared O–H stretching spectra of various 1- and 2-cyano alcohols have been measured, and the presence of intramolecular O–H···π interaction has been detected. Some discussion of the confirmation of such alcohols is given.
  • Tatsuro Ouchi, Kaneyuki Yokoi, Kenzi Yoshimura, Masayoshi Oiwa
    1971 Volume 44 Issue 5 Pages 1339-1342
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The polymerizations of 2-vinyl-4-acryloxy-1,3-dioxolane(VADO) and 2-vinyl-4-methacryloxy-1,3-dioxolane(VMDO), and the copolymerizations of those divinyl cyclic acetals with styrene (St) and acrylonitrile(AN), have been carried out at 60°C, using 2,2′-azobisisobutyronitrile as the initiator. They were discussed kinetically. The following results were obtained: 1) The polymerizations of the above cyclic acetals containing allylidene and vinyl groups proceeded primarily on the acryl or methacryl group, and the allylidene group was extinguished a little by means of cyclization; the ratios of the rate constant of the unimolecular cyclization reaction to that of the bimolecular propagation reaction of the uncyclized radical were 0.065 mol/l (VADO) and 0.114 mol/l(VMDO). 2) The following monomer reactivity ratios were obtained at 60°C: VADO(M1)-St(M2) r1=0.22, r2=0.81; VADO(M1-AN(M2) r1=0.89, r2=0.95; VMDO(M1)-St(M2) r1=0.51, r2=0.49. The Q and e values of the two monomers were calculated from these values: VADO, Q=0.41, and e=0.65; VMDO, Q=0.81 and e=0.38.
  • Akira Takeda, Satosi Wada, Masatosi Fujii, Isao Nakasima, Shoiti Hirat ...
    1971 Volume 44 Issue 5 Pages 1342-1345
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The reaction of alkylchloropyruvate (1) with sodiomalonate gave γ-alkyl-α,β-dialkoxycarbonyl-Δβ,γ-butenolide (2), which led to γ-ketocarboxylic acid (3). The reaction of 1 with sodioacetoacetate gave 2-alkyl-5-methylfuran-3,4-dicarboxylate (6) via the intermediate 2-alkyl-3-hydroxy-5-methyl-2,3-dihydrofuran-3,4-dicarboxylate (5). It has been shown unambiguously that the carbanions of both sodiomalonate and sodioacetoacetate attack the carbonyl carbon of 1 predominantly.
  • Sadatoshi Akabori, Kengo Shiomi, Takeo Sato
    1971 Volume 44 Issue 5 Pages 1346-1347
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Sulfur analogs of [2.2]metaparacyclophane, II, III, and IV were prepared and their NMR spectra were examined. Of the three possible inversion mechanism, the one which involves the inversion of the m-phenylene unit is proposed.
  • Kazuhiko Hotta, Teruo Kubomatsu
    1971 Volume 44 Issue 5 Pages 1348-1352
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Kinetic studies on the hydrogenation of 2-methyl-2-pentenal (UD) over the Raney cobalt catalyst were performed at temperatures ranging from 10 to 40°C in n-hexane. The products were found to be 2-methylpentan-1-ol (SA), 2-methyl-2-penten-1-ol (UA) and 2-methylpentanal (SD). The initial rates of the formation of SA(rSA), SD(rSD), and UA(rUA) were determined in the concentrations of UD(CUD), 0.026–0.263 mol/l. It was found by kinetic analysis that (rSA+rSD) was represented by a Langmuir-type rate equation and rUA by another one. The rate equations which fitted the rate data are as follows.
    rSA+rSD=\frac1.1×1010e−15200⁄RTCUD(1+4.4×105e−7500⁄RTCUD)2
    rUA=\frac1.2×108e−13500⁄RTCUD(1+9.3×103e−5600⁄RTCUD)2
    A mechanism in which the formation of SA and SD and that of UA proceed through different types of adsorbed UD was proposed. The adsorbed species in enol form and that in keto form were considered with respect to the formation of SA and SD. Activation energies for the formation of SA plus SD and of UA were determined to be 7.7 and 7.9 kcal/mol, respectively. The selectivity defined as the ratio of rSA to (rSA+rSD) was found to increase with the increase of the surface coverage of hydrogen.
  • Tadashi Okamoto
    1971 Volume 44 Issue 5 Pages 1353-1357
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Di-μ-acetato-[2,2′-(1-methyleneethylene)bis-π-allyl]dipalladium (I) was obtained (18%) by the reaction of allene and palladium acetate. Its structure was estimated from the data of elemental analysis, molecular weight, hydrogenolysis reaction, IR, and NMR. Complex I was synthesized otherwise by the reaction of allene with di-μ-acetato-2,2′-bi-π-allyldipalladium. The insertion mechanism for the latter reaction was confirmed by the product of the reaction using allene-d4, Pd2(C9H8D4)(CH3COO)2. It was found that this insertion reaction was by far faster than analogous reactions with bis(acetylacetonato)-2,2′-bi-π-allyldipalladium or di-μ-acetato-bis-(π-allyl palladium). The observed acceleration was assumed to be due to strain in the substrate. From NMR data of I and other π-allylpalladium complexes already published, it was shown that the difference in chemical shifts between syn and anti protons of π-allyl complexes is dependent on the substituents on the central carbon; the nonconjugated substituents give smaller values (0,9–1.01 ppm for μ-chloro complexes), and α,β-unsaturated substituents give larger values (1.27–1.28 ppm for μ-chloro complexes). Chloro and acetylacetonato derivatives of I, and the activation energy for spin exchange of saturated methylene protons in I are also described.
  • Satoshi Kambe, Toshio Hayashi, Heinosuke Yasuda, Hiroshi Midorikawa
    1971 Volume 44 Issue 5 Pages 1357-1361
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Thiocyanoacetic esters (I) and aldehydes reacted in the presence of potassium fluoride or carbonate to give α,β-unsaturated ester as a major product and an unexpected solid product (II) as a minor one, which was determined to be N-carbamoyl-2-imino-5-substituted 1,3-oxathiolane-4-carboxylic esters.
  • Oyo Mitsunobu, Koki Kato, Makoto Wada
    1971 Volume 44 Issue 5 Pages 1362-1364
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The reaction of diphenylacetothioanilide with diethyl azodicarboxylate and triphenylphosphine gave rise to the formation of diphenylketene(N-phenyl)imine. Similarly, the reaction of N-(p-tolyl)diphenylacetothioamide gave diphenylketene(N-p-tolyl)imine. On treatment with diethyl azodicarboxylate in the presence of sodium ethoxide, diphenylacetothioanilide afforded bis(N-phenylbenzalimidoyl) disulfide in a good yield. The intermediate of the formation of the ketenimines is also discussed.
  • Masao Okubo, Kazuhiro Maruyama, Jir\={o} Osugi
    1971 Volume 44 Issue 5 Pages 1365-1368
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The orange-colored complex which is formed in the reaction of benzoyl peroxide with Grignard reagent was studied by infrared spectra, and the reaction of the complex with Grignard reagent was also examined. In this complex, the structure of BPO was still maintained by coordinating with magnesium atom through the peroxidic as well as the carbonyl oxygen atoms. Reaction products of this complex with phenylmagnesium bromide were benzoic acid(as Mg-salts), phenyl benzoate, benzophenone, triphenylcarbionol, and bromobenzene. The heterolytic mechanism on the formation of bromobenzene was proposed. The molar ratio of products depended seriously upon the mode of addition of Grignard reagents. The exclusive formation of bromobenzene and Mg-salts of benzoic acid without phenyl benzoate under an experimental condition was explained by assuming the electron-transfer process through the coordinating bond in the complex.
  • Noboru Ono
    1971 Volume 44 Issue 5 Pages 1369-1372
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    When the 2-butyl and 2-pentyl derivatives were treated with tetraethylammonium fluoride in acetonitrile, an olefin-forming elimination took place and an overwhelming Saytzeff orientation was observed. The relative yield of 1-olefin was little affected by changes in the leaving group and β-alkyl group. These results were compared with the results of the eliminations with the conventional base-solvent systems (EtO in EtOH, t-BuO in t-BuOH, and t-BuO in DMSO).
  • Rei Matsueda, Hiroshi Maruyama, Masaaki Ueki, Teruaki Mukaiyama
    1971 Volume 44 Issue 5 Pages 1373-1378
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    A peptide synthesis starting from free N-protected amino acid and free amino acid ester by the use of triphenylphosphine, an oxygen acceptor, and disulfide, a hydrogen acceptor, was studied. The oxidation-reduction condensation reaction affords peptides with high optical purity in excellent yields by simple procedure.
  • Takashi Koyano, Osamu Watanabe
    1971 Volume 44 Issue 5 Pages 1378-1381
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Chlorination of 1-octene with cupric chloride has been investigated in methanol at 110–130°C. The yield of 1,2-dichlorooctane (I) increased by addition of lithium chloride in the reaction mixture, while that of 1-chloro-2-methoxyoctane (II) decreased. Addition of water and cuprous chloride markedly retarded the reaction. The initial rates of formation of I and II could be expressed as v=k[octene]0 [CuCl2]01.6 and v=k[octene]0 [CuCl2]0, respectively. These results can be explained as an initial formation of a complex between olefin and cupric chloride molecule, followed by competitive attack on the complex by chloride ion and methanol. In the less polar reaction media containing more octene, the ratio of I/II increased. This may be ascribed to the steric effect of cupric chloride in the intermediate.
  • Tadashi Sasaki, Shoji Eguchi, Michio Sugimoto
    1971 Volume 44 Issue 5 Pages 1382-1387
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Treatment of 2-endo-cyano-5-norbornene (I) with polyphospholic acid (PPA) at 60°C afforded 6-endo-hydroxybicyclo[2.2.1]heptane-2-endo-carboxylic acid lactone (V) in 40–46% yields, while 2-endo-cyanomethyl-5-norbornene (IV) prepared from 2-endo-methoxycarbonyl-5-norbornene (II) via the corresponding alcohol (III) gave 3-exo-hydroxybicyclo[2.2.1]heptane-2-exo-acetic acid lactone (VIII) in 25% yield by a similar treatment with PPA. With sulfuric acid, IV gave only intractable polymeric materials. However, under milder conditions using a sulfuric acid-acetic acid mixture, IV afforded 2-exo-cyanomethyl- (VI) and 2-exo-carbamoylmethyl-6-exo-acetoxynorbornane (VII) in 69 and 2% yields, respectively. On the other hand, iodolactonization of the carboxylic acid (IX) derived from IV afforded 5-exo-iodo-6-endo-hydroxybicyclo[2.2.1]heptane-2-endo-acetic acid lactone (X) in 68% yield. The formation of VIII from IV was explained by the successive Wagner-Meerwein rearrangement, 3,2- and 6,2-hydride shifts, followed by cyclization.
  • Sango Kunichika, Yasumasa Sakakibara, Mamoru Taniuchi
    1971 Volume 44 Issue 5 Pages 1388-1393
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Allyl iodide has been pyrolyzed in a flow system over a wide range of conditions (temperature, 800–1100°C; contact time, 1.44×10−4–14.0×10−4 sec; concentration, 1.8–6.5 mol%; pressure, atmospheric pressure) in order to find suitable conditions for producing methylacetylene and allene and in order to elucidate the reactions of the allyl radical with iodine or the iodine atom at high temperatures. In addition, a study of the mechanism of the pyrolysis of allyl iodide at high temperatures (800–1100°C) has been made. A total yield of allene and methylacetylene of 10 mol per 100 mol of allyl iodide pyrolyzed was obtained under suitable conditions. In the pyrolysis, little cleavage of the C–C bonds of allyl iodide occurred, and propylene, allene, methylacetylene,diallyl, benzene, and an unidentified product were found to be the main products. By means of the zero-conversion method, diallyl alone has been found to be the major product in the early stage of the pyrolysis, while propylene, allene, methylacetylene, and benzene have been found to be the chief products at higher conversions. On the basis of the observed results, a free-radical mechanism has been proposed for the main reactions. It has further been concluded that the pyrolysis is a radical decomposition initiated by the C3H5I → C3H5·+I reaction and that the overall mechanism in the early stage of the pyrolysis may be represented essentially by the 2C3H5I → C6H10+I2 reaction.
  • Aritsune Kaji, Yoshiaki Araki, Koshin Miyazaki
    1971 Volume 44 Issue 5 Pages 1393-1399
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    The thermal rearrangement of aryl thionocarboxylates was kinetically investigated in diphenyl ether. The rate constants of the rearrangement of aryl N,N-dimethylthionocarbamates were well correlated with the σ values, but the plots of the electron-releasing para-substituents deviated slightly on the lower side of the meta correlation line. A good linear free-energy relationship existed between the rearrangement of aryl N,N-dimethylthionocarbamates and the bimolecular nucleophilic reaction of 4- or 5-substituted 1-chloro-2-nitrobenzenes with piperidine. By the use of the substituent constants obtained from the latter reaction for the electron-releasing para-substituent constants, a fairly good ρ–σ relationship was obtained. Linear free-energy relationships also existed between the rearrangements of aryl N,N-dimethylthionocarbamates and aryl thionobenzoates, and between the rearrangements of aryl N,N-dimethylthionocarbamates and O-aryl S-phenyl dithiocarbonates. The order of the reaction constants was in accord with that of the inductive effects of the α-substituents of the thiocarbonyl group, so the electron-releasing conjugative effects of the α-substituents of the thiocarbonyl group did not play important roles in the rate-determining step. The present results indicate that the thermal rearrangement of aryl thionocarboxylates is an intramolecular SN–Ar which involves a four-membered cyclic transition state formed by a nucleophilic attack of the lone-pair electrons of the thiocarbonyl sulfur atom on the migrating aromatic ring.
  • Yoshio Iwakura, Keikichi Uno, Fujio Toda, Kenjiro Hattori, Minoru Abe
    1971 Volume 44 Issue 5 Pages 1400-1402
    Published: 1971
    Released: March 27, 2006
    JOURNALS FREE ACCESS
    Various transition metals were found to be effective as catalysts in the dehydrocondensation of phenols and silanes.
    R3SiH+PhOH\oversetmetal salt→R3SiOPh+H2
    The effective species were PdCl2, H2PtCl6·6H2O, PtCl2, RhCl3, NiCl2, silane-treated NiCl2, Ptl2, PtS, Raney Ni, Pd-black, Pt-black, Au-black, FeCl3, ZnCl2, CuSO4, CuCl, Cu–Cr, Cu(CH3CO2)·CuO, the methyl ethyl ketoxime complex of Pd, Pt(OX)3, and Pd(OX)2. The ineffective species were metal mirrors of Pd, Au, Ag, Pt, and Cu, and the acetylacetonato complex of Ni, Co(II), Co(III), and Cu. The reaction was then extended to the preparation of polymers containing a Si–O–phenylene linkage in the main chain. Dihydricphenols, e.g., bisphenol A, hydroquinone, 4,4′-dihydroxydiphenyl gave high-molecular-weight polymers with an equimolar amount of a dihydro-silane, e.g., diphenylsilane, p-toluylmethylsilane and p-bisdimethylsilylphenylene, in bulk or in a solvent at temperatures above 150°C. The polymer obtained began to flow above 100°C.
feedback
Top