bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Higher-boiling Compounds on the Liquid-phase Isomerization of m-Xylene over a Silica-Alumina Catalyst under Pressure
Authors: Takaya Haruo , Todo Naoyuki , Hosoya Tadasuke , Oshio Hideki , Yoneoka Mikio , Minegishi Toshio 
Published: July 2006

Abstract
The liquid-phase isomerization of m-xylene was studied over a silica-alumina catalyst under pressure on the additions of 2% of 8 higher-boiling compounds and 20–50% of benzene to reactant m-xylene. The catalyst activity in the isomerization was not greatly affected by hexamethylbenzene, naphthalene, α-methylnaphthalene, diphenyl, or s-dibenzyl. On the other hand, the activity was greatly lowered by 1,6-dimethylnaphthalene, diphenylmethane, and anthracene. Moreover, a very rapid exchange reaction occurred between an aromatic ring of diphenylmethane and a reactant xylene molecule, while the content of the isomerization product decreased linearly with an increase in the amount of benzene. From these results, the chemisorption states of xylene were discussed as follows. Most xylene molecules may be deduced to be chemisorbed on acid sites by those benzene rings. On the other hand, the fact that diphenylmethane inhibits the isomerization implies the existence of such a chemisorption state of xylene as a methylbenzylcarbonium ion, which may be an intermediate in the disproportionation reaction of xylene. The acid sites available for the chemisorption of diphenylmethane and for the disproportionation were speculated to be common and to have both acidic characters, protonic and Lewis.
Directly Bonded Carbon-Hydrogen Coupling Constants of n-Pentane
Authors: Ando Isao , Nishioka Atsuo , Kambe Masao 
Published: July 2006

Abstract
The values of the directly-bonded carbon-hydrogen coupling constants (JC–H) of the methyl and methylene groups in n-pentane were calculated by using the CNDO/2 method, taking into account its rotational isomers, and it was found that the calculated values of JC–H agree closely with the observed values.
Far-infrared Spectra of Zinc Halide Complexes with Acetonitrile
Authors: Kamo Tomoichi , Kimura Masao 
Published: July 2006

Abstract
The infrared spectra of zinc halide complexes with acetonitrile, ZnX2·2CH3CN (X=Cl, Br, I), in the solid state were recorded in the region from 4000 to 96 cm−1. The Zn–N stretching bands for the chloride and bromide were observed, at 210 and 212 cm−1 respectively, as composite bands of the A1 and B1 species. For the iodide, the Zn–N stretching band of the B1 species was observed at 219 cm−1, while the A1 mode was coupled with the Zn–I stretching mode and was absorbed at 252 and 179 cm−1. The N–Zn–N bending bands were observed at 163, 162, and 153 cm−1 and the Zn–N≡C bending bands, at 125, 128, and 132 cm−1, for the chloride, bromide, and iodide respectively. The normal coordinate analysis was carried out by the use of the Urey-Bradley force field, and the Zn–N stretching force constant was obtained as 0.56 mdyn/Å. The force constant is much smaller than the corresponding ones in complexes containing nitrogen donors in the sp3 and the sp2 valency states.
The Isomerization of n-Butenes over Acidic Ion-exchange Resin
Authors: Uematsu Takayoshi 
Published: July 2006

Abstract
The isomerization of n-butenes and the polymerization of propylene were studied in a gas-phase reaction on a sulfonic acid-type resin catalyst. These reactions were considered to proceed via the carbonium ion formation on the functional groups, and a strong correlation was found between the activities in these two reactions. The acidity and the acid strength of the resin catalyst were measured by means of amine titration in a nonpolar solvent using Hammett indicators. The value of the acidity obtained at pKa=6.8 seemed to correspond to the number of the ion-exchangeable hydrogen on the functional groups. The effects of poisoning by ion exchange with Na+, Mg2+ or by adsorption of NH3 were also studied. The decrease in the activity for the isomerization was not proportional to the amount of cations exchanged. The catalytic activities of the protonic hydrogen seemed not to be equal as was suggested by the result of resin catalysts in polar solvents. The possible heterogeneity of the active sites on the resin catalyst was discussed. The six relative rate constants were calculated on the basis of the mutual interconversion among the three isomers of n-butene. The apparent energy of activation for the double-bond migration of 1-butene was found to be 17 kcal/mol on the H-form resin, but it was changed by ion exchange with Na+. The selectivities were characteristic of solid acid catalysts of the protonic type.
Fractionation of Tritiated Water in Potassium Chromium Sulfate Dodecahydrate
Authors: Tanaka Haruhiko , Kado Tsutomu , Negita Hisao 
Published: July 2006

Abstract
A considerable dilution of tritiated water in the water of crystallization was observed in the crystal-growth process of KCr(SO4)2·12H2O from a slightly supersaturated aqueous solution. This was explained in terms of an ionic process in aqueous solution and a surface-diffusion mechanism of crystal growth. It was also found that the tritium content in the hexahydrate was appreciably smaller than that in the liberated water during the course of reaction;
KCr(SO4)2·12H2\xrightarrow[in vacuo]40°CKCr(SO4)2·6H2O+6H2O.
It seems that the step wise dehydration supports the dehydration mechanism proposed by Garner.
Deuteron Magnetic Resonance Studies of Structures and Phase Transitions in the Tantalum-Deuterium System
Authors: Nakamura Keikichi 
Published: July 2006

Abstract
The deuteron magnetic resonance in the tantalum-deuterium system has been measured as a function of the composition (0.45 to 0.198 D/Ta) and of the temperature (90 to −179°C), and the results has been discussed in relation to the neutron diffraction and the heat capacity data. The most probable arrangement of the deuteriums in the polymorphic varieties has been proposed. For the low temperature form β1 form), it has an ordered structure which belongs to the space group A222, with the four tantalums at the 4K positions and the two deuteriums at the 2a positions. Since the deuterium positions are described by a single Z′ principal axis direction, which coincides with the c axis, the quadrupole coupling constant is not averaged by the rapid diffusion of the deuteriums. For the intermediate temperature form (β2 form), a structure constructed with four types of domains has been proposed. In this structure, the space group is the same as that of the β1 form, and the deuterium positions in the domains are 2a, 2b, 2c, and 2d respectively. For the high temperature form (α form), the observed quadrupole coupling constant, which is averaged to zero, can be accounted for if the deuteriums are randomly distributed over all the available tetrahedral sites. However, the calculated configurational entropy based on this assumption is larger than the measured value.
Electron Spin Resonance Study of Amino Acid Radicals Produced by Fenton’s Reagent
Authors: Taniguchi Hitoshi , Hasumi Hideyo , Hatano Hiroyuki 
Published: July 2006

Abstract
Free-radical intermediates in the reaction of the hydroxyl radical with amino acids and structurally related compounds such as alcohols, amine, and carboxylic acids have been studied by ESR spectroscopy using a continuous-flow method. The hydroxyl radical is generated by a ferrous ion-hydrogen peroxide system (Fenton’s reagent). ESR spectra with fairly good signal-to-noise ratios are obtained for the first time in a Fenton’s reagent system from glycine, valine, leucine, glutamic acid, lysine, methionine, tyrosine, ethylamine, acetic acid, pro-pionic acid, n-butyric acid, and succinic acid. Structures, g-values, and hyperfine coupling constants of these radicals are tabulated. The analysis of ESR spectra shows that the same radical species are produced mainly in a Fenton’s reagent system as in a titanous chloride-hydrogen peroxide system. This is consistent with the existence of the hydroxyl radical in both systems. The observed ratio of C2–H to C1–H proton hyperfine coupling constants gives information concerning steric conformations, freedom in the internal rotations, and s-character of the intermediate radicals.
The Temperature Dependence of the Fractionation of Tritiated Water in an Equilibrium between Crystalline Alum and Its Aqueous Solution
Authors: Tanaka Haruhiko 
Published: July 2006

Abstract
The temperature dependence of the fractionation of tritiated water (HTO) was examined during the crystal growth of alum from its tritiated aqueous solution. When the ratios of the mole fractions of HTO in the water of crystallization to that of the mother liquid, S, at various temperatures are compared, the following order is established:
S 19.90≈S29.50&gt;S36.52&gt;S41.95&gt;S47.43&gt;S53.70≈S69.50,
where the suffixes represent the crystallization temperatures, and where S19.90=0.975 and S69.50=0.949. The concept of the hydration of ions developed recently was applied to the problem of the crystal growth from the solution. Two kinetic parameters, such as the relaxation time of the aluminum ion for entering the surface, τc, and that of the hydrated aluminum ion, Al(OH2)63+, for the exchange of the water with bulk water, τe, were taken into account to explain the fractionation. A surface-diffusion mechanism was suggested as essential in the crystal growth of alum from the solution. The activation free energy for the crystal growth from an unstirred solution was found to be 18.17 kcal/mol, a value which was in good agreement with the value given by Bennema.
The Crystal Structure of the Polymerization Catalyst of Acetaldehyde and Its Derivatives. III. The Crystal and Molecular Structure of the Bis(dimethylaluminum N-Phenylbenzimidate-Acetaldehyde) Complex, [(CH3)2Al·O·C(C6H5):N(C6H5), CH3CHO]2
Authors: Kai Yasushi , Yasuoka Noritake , Kasai Nobutami , Kakudo Masao 
Published: July 2006

Abstract
The molecular structure of a stereospecific (isotactic) polymerization catalyst of the acetaldehyde-monomer complex, [Me2Al·O·CPh: NPh,MeCHO]2, has been determined on the basis of three-dimensional X-ray data collected photographically. The crystal belongs to the orthorhombic system (space group Pcca) with four dimer formula units in a cell with the dimensions of: a=15.83(3), b=12.61(1), and c=17.66(1) Å. The structure was established by the heavy-atom method and refined by block-diagonal, least-squares procedure. The molecule is dimeric and has a C2-2 symmetry. A monomer molecule, acetaldehyde, is inserted in the Al–N bond of the original polymerization catalyst. The oxygen atom bridges both aluminum atoms, Al–O=1.858(6) and 1.985(6) Å. The α-carbon atom of acetaldehyde bonds to the nitrogen atom of the amide moiety, C–N=1.469(12) Å. The aluminum atom is penta-co-ordinated and has a trigonal bipyramidal conformation.
The Crystal Structure of the Polymerization Catalyst of Acetaldehyde and Its Derivatives. IV. The Crystal and Molecular Structure of Dimethylaluminum N-Phenylbenzimidate-O-(Trimethylaluminum)-Acetaldehyde Complex, [(CH3)2Al·O·C(C6H5):N(C6H5), CH3CHO, Al(CH3)3]
Authors: Kai Yasushi , Yasuoka Noritake , Kasai Nobutami , Kakudo Masao 
Published: July 2006

Abstract
The molecular structure of a stereospecific (isotactic) polymerization catalyst of the acetaldehyde-monomer-Lewis acid complex, [Me2Al·O·CPh:NPh,MeCHO,AlMe3], has been determined from three-dimensional X-ray-diffraction data collected photographically. The crystal belongs to the monoclinic system (space group P21⁄n), with four formula units in a cell with dimensions of: a=13.60(3), b=13.74(2), c=12.40(2) Å, β=95.9(2)°. The structure was solved by the heavy-atom method and was refined by the block-diagonal, least-squares procedure. The trimethylaluminum forms a bond with the electron-rich oxygen atom of acetaldehyde through the electron-deficient aluminum atom. The polymerization mechanism can reasonably be concluded to be the “co-ordinated cationic polymerization”.
Conditions Favorable for the Formation of γ-FeOOH by Aerial Oxidation in an Acidic Suspension of Iron Metal Powder
Authors: Kiyama Masao , Akita Toshikazu , Shimizu Shigeki , Okuda Yoshiro , Takada Toshio 
Published: July 2006

Abstract
Dilute solutions of ferrous sulfate, sulfuric acid, hydrochloric acid, nitric acid and acetic acid in which iron powders are dispersed have been oxidized at below 80°C by blowing air into them. The resulting precipitates have been examined by means of X-ray diffraction, chemical analysis and optical and electron microscopy. When the iron powder is well dispersed, γ-FeOOH is formed with or without α-FeOOH, α-Fe2O3, or Fe3O4. The mode of formation depends on such factors as particle size, amount of iron powder, kind of anion present and temperature. Particle size greatly influences the formation of γ-FeOOH in the sulfate system, but not in the other systems.
Determination of the Formation Constants of Actinoid and Lanthanoid Lactate Complexes by Means of Electrophoresis
Authors: Sakanoue Masanobu , Nakatani Mitsuo 
Published: July 2006

Abstract
Determination of the complex formation constant of actinides (Am, Cm) and lanthanides (Pm, Eu, Lu) with lactic acid was carried out by means of the electrophoretic method. “Cellogel”, a gelatinized cellulose acetate was used as the supporting medium for electrophoresis at 10°C. Electrolyte solutions of various pH at an ionic strength of 1.5 were prepared from 0.5m lactic acid solution for electrophoresis at various pH values. The migration zones of α- and β-emitter were determined by α track on cellulose nitrate and autoradiographic image on X-ray film, respectively. The mobility of each nuclide at different pH was analyzed to obtain the formation constants of lactate complex of each element with reference to dissociation equilibrium. The β1 values thus obtained were consistent with those obtained by other methods. The method was found to be especially useful for determining the complex formation constants of trans-uranium elements with only tracer amounts of these elements.
Potentiometric Titration of Iron(III) with Hydrazine Sulphate at Room Temperature
Authors: Rao G Gopala , Rao P V Krishna , Rao G Bala Bhaskara 
Published: July 2006

Abstract
Conditions have now been developed for a direct potentiometric titration of iron(III) with hydrazine sulphate at room temperature. Osmium tetroxide markedly catalyses the reaction in medium of 2.0–3.0 pH. Under the conditions prescribed four moles of iron(III) are reduced per every mole of hydrazine oxidised. Application of the new method to the assay of iron(III) in an alloy is also considered.
Substituent Effects on Suspected Phenonium Ion Reactions
Authors: Kingsbury Charles A , Best D C 
Published: July 2006

Abstract
The stereochemistry of the various conversions in the 1,2-diphenyl-1-propyl system was measured as a function of aromatic substituent. For β-anisyl groups the reaction occurred with retention of configuration. For compounds with indifferent electron donating aryl groups, the conversions were stereoselective forming mostly threo product. For β-p-nitrophenyl groups the stereochemical course of the reaction was “racemization.” The latter reactions were associated with the presence of open ions. In certain reactions, acetate products were formed in low yield with retention of configuration, irrespective of substituent. The kinetics of ethanolysis were consistent with (partial) bridged ion formation for the threo isomers and with extensive open ion formation for the erythro species.
The Determination of Sulfide- and Sulfate-Sulfur in Igneous Rocks with Tin(II)-Strong Phosphoric Acid and Strong Phosphoric Acid
Authors: Nagashima Shigeru , Yoshida Minoru , Ozawa Takejiro 
Published: July 2006

Abstract
A method for the determination of minute amounts of sulfide- and sulfate-sulfur in igneous rocks was investigated. A rock sample is easily dissolved by heating with tin(II)-strong phosphoric acid or strong phosphoric acid. When the rock sample is dissolved with tin(II)-strong phosphoric acid, total-sulfur is evolved as hydrogen sulfide. With strong phosphoric acid, sulfide-sulfur is evolved as hydrogen sulfide, but sulfate-sulfur is not. The hydrogen sufide evolved is fixed as zinc sulfide, and then determined by the photometric method, using mercuric thiocyanate and ferric iron. The conditions for separating sulfide- and sulfate-sulfur in rocks were examined by using samples which had been prepared by mixing rock or silica (each of them, &lt;0.001% S) with sulfides or sulfates. The application of the method to some igneous rock samples gave results with a coefficient of variation of about 5% for sulfur contents of 0.01–0.02%. The sulfur in samples with more than 0.001% can be determined by using about 0.1 g of samples. The sulfide- and sulfate-sulfur in two standard rock samples were also determined: W-1 (Total-S, 0.012%; Sulfide-S, 0.005%; Sulfate-S, 0.007%) and G-1 (Total-S, 0.004%, Sulfide-S, &lt;0.001%; Sulfate-S, 0.004%).
Isomerism of the Metal Complexes Containing Multidentate Ligands. II. The Cobalt(III), Cobalt(II), and Nickel(II) Complexes of N,N,N′,N′-Tetrakis(2-aminoethyl)ethylenediamine and-1,2-propanediamine and Their Absolute Configurations
Authors: Yoshikawa Yuzo , Fujii Ekyo , Yamasaki Kazuo 
Published: July 2006

Abstract
The cobalt(III), cobalt(II), and nickel(II) complexes of N,N,N′,N′-tetrakis(2-aminoethyl)ethylenedianime and -1,2-propanediamine were prepared, and the cobalt(III) complex of the former ligand was resolved by fractional crystallization and column chromatography on SE-Sephadex. The absolute configurations of the cobalt(III) complexes were assigned on the basis of the stereospecificity of the latter ligand; they were later confirmed by the X-ray analysis. The electronic absorption, circular dichroism, and optical rotatory dispersion spectra of the complexes prepared were also measured.
Electron Spin Resonance during Photolysis of p-Benzoquinone and Its Derivatives in Ethanol
Authors: Yoshida Hiroshi , Hayashi Koichiro , Warashina Tetsuo 
Published: July 2006

Abstract
Electron spin resonance measurements were carried out at room temperature during photolysis of solutions containing p-benzoquinone, 2-methyl-p-benzoquinone, 2,5-dimethyl-p-benzoquinone and 1,4-naphthoquinone in ethanol. From all quinones, the semiquinone radicals and semiquinone anions are found to form simultaneously. When the solution is made acidic, the semiquinone anion transforms into the semiquinone radical, so that the spectrum of the latter is easily determined. For benzoquinone, the semiquinone radical is formed efficiently by light of λ≈300 nm, and has a life of about 0.05 sec. The semiquinone anion is formed by light of λ≈460 nm and is rather long-lived (about 0.5 sec). These results suggest that the semiquinone anion may be formed mostly by photodissociation of charge-transfer complex between benzoquinone and alcohols. Observed proton hyperfine coupling constants were subjected to the molecular orbital treatment. The coupling constants in all the semiquinone anions examined are well interpreted by McLachlan’s approximate SCF-MO method and Colpa-Bolton’s relation with Q=27G and K=12.8 G However, good agreement is not attained between the observed coupling constants and the calculated ones for the semiquinone radicals.
Positive Charge Distribution of Secondary Alkylamines and Its Correlation with the Bond-Scission Probability Appearing in Their Mass Spectra
Authors: Yamamoto Masao , Fujita Iwao , Itoh Michiyasu , Hirota Kozo 
Published: July 2006

Abstract
With respect to the correlation between scission probabilities and positive charge distributions on the skeletal bonds of amines appearing in their mass spectra, further research is reported on four secondary amines (diethylamine, dipropylamine, dibutylamine and methylbutylamine). In each secondary alkylamine the fragment ions formed by the scission of α–CC bond are the most abundant experimentally, i.e., the scission probability of α–CC bond is the largest in monoamines as well. Agreement between experiments and LCBO-MO calculations on four secondary alkylamines is found to be satisfactory as in the case of propylamine, using the same semi-empirical parameters as those of monoamines in the calculation. It is shown that from detailed calculations of diethylamine by CNDO method the scission of α–CC bond is also easy due to concentration of the positive charge at the bond, theoretically in accordance with the semi-empirical calculation. Change of mass spectra vs. ionizing voltage is explained on a generalized scheme, which combines two existing theories of fragmentation (QET and MOT).
The Resonance Raman Effect of Azobenzene and p-Aminoazobenzene
Authors: Koide Shiro , Udagawa Yasuo , Mikami Naohiko , Kaya Koji , Ito Mitsuo 
Published: July 2006

Abstract
The resonance Raman spectra of azobenzene and p-aminoazobenzene were measured precisely at various excitation wavelengths. It was found that the π–π* excited state played a dominant role in the Raman intensities but not the n–π* excited state and that there was no correlation between the Raman intensity and the absorption coefficient at excitation wavelength.
Mass Spectrometry of 1-Phenylazo-2-naphthols
Authors: Kobayashi Kousuke , Kurihara Kenji , Hirose Kazutoyo 
Published: July 2006

Abstract
In order to examine the azo-hydrazone tautomerism of substituted 1-phenylazo-2-naphthols and to estimate the effect of substituents on the equilibrium, mono-substituted 1-phenylazo-2-naphthols were synthesized and the spectra were compared with those of the respective acetylated derivatives and β-naphthoquinone-methylphenylhydrazone as references of the azo and hydrazone forms respectively. The spectra of acetylated derivatives show the same pattern as those of the original samples except for the molecular ion and ion at m⁄e: 43. Moreover, β-naphthoquinone-methylphenylhydrazone displays a different fragmentation process, the cleavage of the N–N bond. In conclusion, the substituted 1-phenylazo-2-naphthols exist in the gaseous state as only the azo form; this is different from the results in the liquid and solid states. The fragmentation processes, in which the reactions of M+→ (m⁄e: 171)+→ (m/e: 143)+→(m⁄e: 115)+ mainly occur, are clarified on the basis of these results. The effect of substituents on the reaction rate of the formation of ions at m⁄e: 171 from molecular ions is examined. The correlation with the Hammett σ constants is ρ=0.078 for meta substituents, and the plots for para substituents lie under the line, which means that the reaction rate for para substituents is slow. This is explained on the basis of the resonance effect.
The Stereoselective Reactivities of Dl-Amino Acid N-Carboxyanhydrides for (−)-Menthol
Authors: Hayakawa Tadao , Yamamoto Hiroyuki , Murakami Yukiko , Yobiko Yoshihiro , Mitani Shunji 
Published: July 2006

Abstract
The stereoselective reactivities of some neutral Dl-amino acid N-carboxyanhydrides for (−) -menthol were studied by varying the concentration of hydrogen chloride as a catalyst and the reaction temperature. From the results of gas-liquid-chromatographic analyses, the esterification rates of d-amino acids were shown to be higher than those of l-amino acids in all cases. The highest ratio of the esterification rate, VD⁄VL, is 2.37. The recovered unreacted amino acids were always enriched in the l-form. The stereoselective reactivities were influenced by the catalyst concentration and not influenced by the reaction temperature.
Studies of Dithiobiurets. III. The Preparation and Properties of 3,5-Disubstituted 3H-1,2,4-Dithiazoles
Authors: Iwataki Isao 
Published: July 2006

Abstract
3,5-Disubstituted 3H-1,2,4-dithiazoles were prepared by the oxidation of dithiobiurets, S-benzylisodithiobiurets, and alkyl trithioallophanates, and then 3-acyl or carbamoylimino derivatives were obtained by the direct acylation or carbamoylation of the dithiazole salts. From the spectral data of these compounds, it is concluded that the carbonyl group affects the pseudoaromatic character of the dithiazole ring system.