bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Various Gas-Pretreatments of the Fe Powder, Prepared by the Reduction of FeI2 with Potassium Metal, on the Catalytic Properties in Fischer–Tropsch Synthesis
Authors: Miyake Mikio , Hamaguchi Maki , Nomura Masakatsu , Shimada Hiromichi , Nishijima Akio 
Published: July 2006

Abstract
Fischer–Tropsch (F–T) synthesis was carried out on the Fe powder catalyst prepared by the reduction of FeI2 with potassium metal in refluxing tetrahydrofuran (THF). 1-Butene was obtained with 37 wt% selectivity and a rather high conversion of 12 wt% by an autoclave system at 553 K. After H2-pretreatment of the Fe powder at 573 K, propylene was produced as the major product (15 wt% selectivity) under otherwise the same experimental conditions. In a conventional flow system with a stream of H2, H2/CO, and CO during a heatup period of the reactor to 533 K, C3, C4, and C5 olefins were produced as major products, respectively. The synthesized Fe powder contains 1.6 wt% of carbon, which may be produced by the decomposition of THF in preparation of the catalyst. During the gas-pretreatment of the Fe powder in the flow reactor, evolution of CH4 CO2, and CO was observed. The amount of carbon on the Fe powder produced after the gas-pretreatment varied with the pretreatment gas in the order, CO &gt; H2/CO &gt; H2. Quantitative X-ray photoelectron spectroscopy (XPS) analysis of the Fe powder surfaces indicates that a significant amount of carbonaceous species is accumulated during the F–T reaction, and that the accumulation of such species can be avoided by the H2-pretreatment of the Fe powder. The change in surface properties by the gas-pretreatments is discussed in relation to the corresponding change of the product distribution in the F–T synthesis.
Energetics of Silver Alloys. Enthalpies of Mixing and Formation in the Systems Silver–Aluminium and Silver–Tin
Authors: Badawi Walid , El-Talbi Mohamed , Oun Ahmed M 
Published: July 2006

Abstract
The paper presents values of the enthalpies of mixing and formation in the systems Ag–Al and Ag–Sn. Appropriate polynomial functions for the composition dependence of the enthalpies of mixing and formation and their partial molar quantities are given. The behaviors of the integral and partial molar enthalpies of mixing and formation are discussed. The trend of the enthalpy of formation in the system silver–tin points out the existence of the compound Ag–Sn in the solid state. The enthalpy of formation in the system Ag–Sn depends insignificantly on the temperature, while that in the system Ag–Al displays a pronounced temperature dependence which is attributed to lattice defects in the structure. A pronounced temperature dependence of the enthalpy of formation seems, therefore, not to be a general property of all metallic alloys.
Catalytic Oxidation–Reduction Hydration of Olefin with Molecular Oxygen in the Presence of Bis(1,3-diketonato)cobalt(II) Complexes
Authors: Kato Koji , Yamada Tohru , Takai Toshihiro , Inoki Satoshi , Isayama Shigeru 
Published: July 2006

Abstract
In the presence of a bis(1,3-diketonato)cobalt(II) complex, various olefins are converted to the corresponding hydrated products according to the Markownikov rule on treatment with molecular oxygen in secondary alcohol (“oxidation–reduction hydration”). Removal of water formed during the hydration reaction, especially by azeotropic method, is remarkably effective to improve yields of the hydrated products based on the cobalt(II) catalyst as bis(trifluoroacetylacetonato)cobalt(II) (Co(tfa)2) or bis(2-ethoxycarbonyl-3-oxobutanalato)cobalt(II) (Co(ecbo)2).
The Oxidation of 2,6-Di-tert-butyl-4-methylphenol Using Hydrogen Peroxide-Heteropolyacid System
Authors: Shimizu Masao , Orita Hideo , Hayakawa Takashi , Watanabe Yoshihito , Takehira Katsuomi 
Published: July 2006

Abstract
The oxidation of 2,6-di-tert-butyl-4-methylphenol (1) with hydrogen peroxide in the presence of heteropolyacids was carried out in acetic acid to give 2,6-di-tert-butyl-4-hydroperoxy-4-methyl-2,5-cyclohexadien-1-one (2), 2,6-di-tert-butyl-4-hydroxy-4-methel-2,5-cyclohexadien-1-one (3), and 2,6-di-tert-butyl-p-benzoquinone (4). Conversion of 2 into 4 under acidic conditions suggests that 2 could be a precursor of 4. The oxidation mechanism of phenols was discussed based on isolated intermediates.
Stereoselective Synthesis of (E)-2-Hydroxyimino-2-phenylacetonitrile by Photolysis of 4-Azido-3-phenylfurazan 2-Oxide
Authors: Kunai Atsutaka , Doi Takanori , Nagaoka Takashi , Yagi Hirofumi , Sasaki Kazuo 
Published: July 2006

Abstract
Synthesis of (E)-2-hydroxyimino-2-phenylacetonitrile from styrene was examined. This compound was obtained selectively by the photolysis of 4-azido-3-phenylfurazan 2-oxide.
Systematic Enumerations of Compounds Derived from D3h Skeletons. An Application of Unit Subduced Cycle Indices
Authors: Fujita Shinsaku 
Published: July 2006

Abstract
The table of unit subduced cycle indices (USCIs) for D3h is constructed and applied to the enumerations of chemical structures by starting from various parent skeletons of D3h symmetry i.e., a trigonal bipyramid, an iceane skeleton, and a pirsmane skeleton. The substitution positions of these skeletons are divided into orbits governed by coset representations. According to the division of such a skeleton, subduced cycle indices (SCIs) are constructed to enumerate chemical structures with respect to their symmetries. The introduction of figure inventories into the SCIs and the subsequent expansion give generating functions for counting fixed points. The resulting matrix of fixed points is multiplied by the inverse of a mark table to afford the number of isomers with each molecular formula and each subsymmetry.
Activation Process of CuY Zeolite Catalyst Observed by TPR and EXAFS Measurements
Authors: Tanabe Shuji , Matsumoto Hiroshige 
Published: July 2006

Abstract
EXAFS measurements have been employed to investigate structural changes of Cu species in Y-zeolite during TPR process. The formation of an active species by a consecutive reduction-reoxidation treatment was clearly demonstrated in the TPR spectra. Detailed analysis of the EXAFS data suggested that at a considerably low temperature the active species was reduced directly to Cu metal with a particle size of 5–8 Å, while at higher temperatures the original Cu2+ ions were reduced by a two-step mechanism, via Cu+ ions to Cu metal. From these points of view, the active species is considered to be small clusters of CuO with several Cu atoms.
Fluorometric Determination of Ethylenediamine Using a Beryllium-Schiff Base Complex
Authors: Aoki Izuo , Takahashi Akira , Watanabe Kunihiro 
Published: July 2006

Abstract
Ethylenediamine (en) reacts with salicylaldehyde and beryllium(II) in a weakly basic solution to form a fluorescent beryllium(II)-Schiff base complex. A fluorometric method for the determination of en by using the beryllium(II) complex has been established. Ethylenediamine could be determined in 2×10−7–2×10−5 mol dm−3 within a relative standard deviation of 3%. The detection limit of en was 8×10−9 mol dm−3. Ammonia, diethylamine, and triethylamine does not interfere with the determination of en. The present method has been applied to the analysis of en in aminophylline tablets. The fluorometric method for the determination of trace amount of amino acid by using an aluminum(III)-Schiff base complex has also been investigated.
Selectivity of Coordination Sites in Ni(II), Zn(II), and Cd(II) Complexes with 7-[(3,5-Dichloro(or bromo)-2-pyridyl)azo]-8-hydroxyquinoline-5-sulfonic Acid
Authors: Huang Hu , Chikushi Hiroaki , Nakamura Masaaki , Kai Fumiaki 
Published: July 2006

Abstract
A new multidentate ligand, 7-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-8-hydroxyquinoline-5-sulfonic acid (sodium salt, abbr. as 3,5-di-X-PAHQS, X=Cl or Br) which contains pyridylazonaphthol (PAN) and 8-quinolinol skeletons, was prepared for the first time in order to investigate its coordination behavior toward metal(II) ions. For comparative studies, the ligands (2-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-1-hydroxynaphthalene-4-sulfonic acid (sodium salt, abbr. as 3,5-di-X-αPANS, X=Cl or Br), 1-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-2-hydroxynaphthalene-6-sulfonic acid (sodium salt, abbr. as 3,5-di-X-βPANS, X=Cl or Br), and 7-[(4-chloro or unsubstituted phenyl)azo]-8-hydroxyquinoline-5-sulfonic acid(sodium salt, abbr. as 4-Cl-BAHQS for chloro substituted phenyl and BAHQS for unsubstituted phenyl, respectively)) were also prepared. The coordination modes of the synthesized multidentate ligands with Ni(II), Zn(II), and Cd(II) ions were investigated both spectrophotometrically and polarographically, in aqueous solution. Judging from the variations of the reduction potentials of the azo group with metal complexations, in the case of the ligands of BAHQS systems, the azo group did not participate in complexation. On the contrary, for the ligands of the PAN and PAHQS systems, the azo group in these ligands clearly participated in metal-complexation. On the basis of the results of polarographic studies and of spectral data, the complexing equilibria of these complexes were analyzed and the stability constants calculated. The dissociation constants and the reduction potentials of these new ligands are also discussed.
ESR Studies of the Competitive Adsorption Behavior of Poly(methyl methacrylate) and Polystyrene Mixtures at the Solid–Liquid Interface
Authors: Kobayashi Kazutoshi , Sugimoto Shizuo , Yajima Hirofumi , Araki Kazuo , Imamura Yoshio , Endo Ryuichi 
Published: July 2006

Abstract
The adsorption from solution of polystyrene and poly(methyl methacrylate) mixtures on a silica surface was studied in order to establish the competitive adsorption behavior of these polymers. The fractions of train segment for these polymers were determined from the ESR spectra analyses, and these values were compared with those of the individual adsorption. When the initial concentrations of the polymer mixtures in solution were fixed and the added amounts of silica adsorbent were varied, the adsorption of polystyrene did not take place until the poly(methyl methacrylate) in solution was completely exhausted. In the simultaneous adsorption, the amount of adsorption of poly(methyl methacrylate) was affected by the presence of polystyrene in the solution. On the other hand, the amount of adsorption of polystyrene was unaffected by the presence of poly(methyl methacrylate) in the system. The conformation of the adsorbed poly(methyl methacrylate) was also affected by the presence of polystyrene when they were simultaneously adsorbed on the silica surface. The conformation of the poly(methyl methacrylate) adsorbed from the mixed solution formed a more compressed polymer layer in comparison with that for the case where the poly(methyl methacrylate) was adsorbed alone.
The Creation of a Skin-Core Structure in Petroleum Derived Mesophase Pitch Based Carbon Fiber
Authors: Zeng Shu-Ming , Korai Yozo , Mochida Isao , Hino Takashi , Toshima Hiroshi 
Published: July 2006

Abstract
Stabilization of a petroleum-derived mesophase pitch (P-MP) fibers was investigated in order to create a skin-core structure in the carbonized fibers. The pitch fibers were either oxidatively stabilized at 270°C in air or 10 vol% O2 for short periods, or oxidized in air for 15 min and successively extracted by tetrahydrofuran (THF) for 30 min. A skin-core structure could be observed in the carbonized fibers under a polarized-light microscope or SEM. The relationship between the oxidative reactivity of P-MP fiber and creation of a skin-core structure, and the effect of solvent extraction for the creation are discussed according to the results.
Synthesis of Nickel and Magnesium Phyllosilicates with 1:1 and 2:1 Layer Structures
Authors: Mizutani Tadashi , Fukushima Yoshiaki , Okada Akane , Kamigaito Osami 
Published: July 2006

Abstract
Nickel and magnesium phyllosilicates with 1:1 and 2:1 layer structures were prepared from silicic acid and metal chlorides (NiCl2 or MgCl2) in water. The phyllosilicates were allowed to crystallize at room temperature or 200°C. The 1:1 and 2:1 phyllosilicates were selectively prepared by adjusting the metal ion to silicon ratio (M/Si) in the starting mixtures. The 1:1 phyllosilicate was crystallized from the starting mixture with an M/Si ratio of 1.5 and the 2:1 phyllosilicate was crystallized from the mixture with an M/Si ratio of 0.5. The increase in the OH−/M ratio in the starting mixture accelerated the crystallization to phyllosilicates. Crystallization to the phyllosilicates occurred even at room temperature, and a hydrothermal treatment at 200°C accelerated this process. The crystal size of the 1:1 phyllosilicates was larger than that of the 2:1 phyllosilicates. The nickel phyllosilicates crystallized faster than the magnesium phyllosilicates. These results can be explained by assuming successive copolymerization reactions of silicic acid and aqua metal ions, in which an intermediate with a 1:1 structure is involved. The acidity of the aqua metal ions plays an important role in the mechanism of the copolymerization process.
Preparation of 1-Aryl- or 1-Alkenyl-2-(perfluoroalkyl)acetylenes
Authors: Yoneda Norihiko , Matsuoka Shigeru , Miyaura Norio , Fukuhara Tsuyoshi , Suzuki Akira 
Published: July 2006

Abstract
1-Aryl- or 1-alkenyl-2-(perfluoroalkyl)acetylenes were produced in high yields by the coupling reaction of aryl or alkenyl iodides with (perfluoroalkynyl)zinc compounds prepared from the corresponding (perfluoroalkyl)acetylenes in the presence of Pd catalyst.
Miscibility of 1-Octanol and 2-(Octylsulinyl)ethanol in the Adsorbed Film and Micelle
Authors: Matsuki Hitoshi , Kanda Tomoko , Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
The surface tension of the aqueous solution of 1-octanol and 2-(octylsulfinyl)ethanol (OSE) mixture was measured as a function of the total molality of surfactants and the composition of OSE in the total surfactants at 298.15 K under atmospheric pressure. It was observed that 1-octanol molecules form mixed micelles with OSE molecules in the composition range above 0.850. The corresponding composition in the mixed adsorbed film was evaluated numerically by applying the thermodynamic relations developed previously. It was found that the surfactant molecules mix with each other in all proportions in the adsorbed film and the composition in the adsorbed film is smaller than that in the solution. Further, the adsorbed film was found to be richer in 1-octanol than the micelle at the critical micelle concentration (cmc). This behavior was attributed to the fact that 1-octanol is more surface active than OSE though it does not form the micelle.
Photoelectron Spectra of Polypyrrole: The Effect of the Ambient Atmosphere to the Spectra
Authors: Hino Shojun , Iwasaki Kentaro , Tatematsu Hideki , Matsumoto Kazuo 
Published: July 2006

Abstract
Ultraviolet and X-ray photoelectron spectra of carefully prepared undoped as well as doped polypyrrole have been measured. Reliable UPS of undoped polypyrrole must be the first one in spite of its popularity, because of its instability in the air. Our UPS were compared with those of presumably polymerized pyrrole by X-ray irradiation and other reported results. We examined the validity of these spectra and we found the deformation of the UPS caused by air exposure of the undoped film. A comparison of our UPS with theoretical calculation gave 1.40 Å as an estimated bond distance between α,α′ carbon atoms. Both Cls and Nls XPS were asymmetric and consisted of a few peak components, which was not dependent on doping. Their peak envelopes varied with its historical back ground. While the Cls peak envelopes were not deformed so seriously by air exposure, the Nls envelopes were affected by slight air exposure as were observed in the UPS.
Synthesis, Structure, and Magnetism of Binuclear Cu(II)Cu(II), Cu(II)Ni(II), and Ni(II)Ni(II) Complexes Doubly Bridged by Oxymate Groups
Authors: Luneau Dominique , Oshio Hiroki , Okawa Hisashi , Koikawa Masayuki , Kida Sigeo 
Published: July 2006

Abstract
Binuclear complexes, [Cu(L)Cu(L′)(H2O)2]X2 (H2L=3,3′-trimethylenedinitrilobis(2-butanoneoxime) (H2dopn) or 3,3′-ethylenedinitrilobis(2-butanoneoxime) (H2doen); L′=2,2′-bipyridyl (bpy) or 1,10-phenanthroline (phen); X=ClO4 or NO3), [Ni(dopn)Cu(bpy)(H2O)](ClO4)2, and [Ni(dopn)Ni(bpy)2](ClO4)2, have been prepared and characterized. The structure of [Cu(dopn)Cu(phen)(CH3OH)2](ClO4)2 (di-methanol adduct) has been determined by single crystal X-ray method. The Cu(dopn) molecule coordinates to the second copper(II) ion through the deprotonated oximate oxygens to afford a binuclear structure doubly bridged by the oximate groups in the cis arrangement. The binuclear cation is bent at the oxymate oxygens with a dihedral angle of 26.7(2)°. The binuclear copper(II) complexes show a characteristic visible band of significant intensity (ε 2700–2900 dm3 mol−1cm−1) near 22000 cm−1 and a strong intramolecular antiferromagnetic spin-exchange interaction. The exchange integrals (J) are evaluated to be −413.3–−433.0 cm−1. The magnetic moment (per molecule) of the nickel(II)–copper(II) complex is 1.80 μB at room temperature and the moment of the binuclear nickel(II) complex is 2.94 μB, demonstrating that the Ni(dopn) entity of these complexes is diamagnetic.
Et3B Induced Stereoselective Radical Addition of Ph3GeH to Carbon–Carbon Multiple Bonds and Its Application to Isomerization of Olefins
Authors: Nozaki Kyoko , Ichinose Yoshifumi , Wakamatsu Kuni , Oshima Koichiro , Utimoto Kiitiro 
Published: July 2006

Abstract
Triphenylgermane easily adds to acetylenes or terminal olefins in the presence of Et3B to give alkenyltriphenylgermane or alkyltriphenylgermane respectively under excellent control of regio- and stereoselectivities. While Et3B catalyzed addition of Ph3GeH to 1-dodecyne at −78 °C affords (Z)-1-triphenygermyl-1-dodecene exclusively, the addition of Ph3GeH at 60 °C provides (E)-1-triphenylgermyl-1-dodecene as a single product. The triphenylgermyl radical is also effective to isomerize Z-olefins into their thermodynamically more stable E-isomers.
Effects of Branching of the Ester Alkyl Chain on the Mesomorphic Properties of Alkyl 4-[4-(4-Substituted benzoyloxy)benzylideneamino]benzoates
Authors: Matsuzaki Hiroyuki , Matsunaga Yoshio 
Published: July 2006

Abstract
The mesomorphic properties of five homologous series of alkyl 4-[4-(4-X-substituted benzoyloxy)benzylideneamino]benzoates, where X=CN,NO2, CH3, Cl, and CH3COO, have been studied. The ester alkyl groups employed were the following eleven types: ethyl and propyl and their mono-, di-, and trimethyl-substituted ones. Although the introduction of the first branching methyl group to the ester alkyl chain depresses the nematic stability, the second and/or third groups may either further depress or enhance the stability, depending upon the nature of the substituent X. While all of the members of the cyano and nitro derivatives are purely nematogenic, many members of the other three series display a smectic A phase, as well as a nematic phase. In addition to the above-mentioned esters, the butyl, pentyl, and their monomethyl-substituted esters were examined in order to demonstrate that the effects on the thermal stability of the smectic A phase of the branching of the ester alkyl chain and those of the substituent X are also interdependent.
Functionalized Bilayer Membranes as Artificial Tryptophan Synthase. Characterization of Catalytic Efficiency, Substrate Specificity, and Reaction Selectivity
Authors: Murakami Yukito , Kikuchi Jun-ichi , Hisaeda Yoshio , Nakamura Koichiro , Kitazaki Tomoyuki , Kaya Hidenori 
Published: July 2006

Abstract
Functionalized bilayer membranes having vitamin B6 activity effectively catalyzed β-replacement reactions of serine with indoles to afford the corresponding tryptophan derivatives in aqueous media under mild conditions. Catalytic capability of the present artificial enzyme was subjected to change by changing a combination of molecular components constituting the catalyst system. The structural mode of a hydrophobic pyridoxal derivative as the coenzyme model, the catalytic ability of an amino acid residue placed in a peptide lipid which forms single-walled bilayer vesicles as the apoenzyme model, and the coordination property of added metal ions were found to be responsible for the overall catalytic performance. Multifunctional assistance was observed in the β-replacement reaction of serine with indole, and the reaction proceeded in preference to other side reactions, such as β-elimination, dealdolation, and transamination reactions. Substrate selectivity was found to be primarily dependent on the nucleophilicity of indole derivatives.
Fading Mechanism of Paint Films Composed of Insoluble Azo Pigment and Titanium Dioxide
Authors: Okamoto Shingo , Ohya-Nishiguchi Hiroaki 
Published: July 2006

Abstract
The fading mechanism of paint films comprising an insoluble azo pigment and titanium dioxide was investigated using ESR and FT-IR spectrometers and the results of outdoor exposure tests. Some paramagnetic species were found in paint films at room temperature. They showed no hyperfine structure and their g-values drastically changed according to sample preparation, the measurement temperature and treatments with a base or acid. These paramagnetic species are proposed to be O2− in an adsorbed state on a TiO2 surface and O− of the TiO2+. It is suggested that film fading occurs through an attack of these active oxygens on the insoluble azo pigment.
Methoxybromination of Cinnamic Acid by N-Bromosuccinimide
Authors: Karunakaran C , Venkatachalapathy C 
Published: July 2006

Abstract
With cinnamic acid in aqueous methanol N-bromosuccinimide yields 2-bromo-3-methoxy-3-phenylpropionic acid. It is a second-order reaction independent of [H+] at moderately high [H+]. At low [H+] the rate increases with decrease in [H+]. The reaction is inhibited by succinimide. The reaction rate decreases with increase in methanol content of the medium. Mechanistic pathways of the reaction are discussed and a rate equation is derived.
Oxidation of Aromatic Alcohols with Chromium(VI) Trioxide in the Presence of “Wet-Aluminium Oxide” in Aprotic Solvent
Authors: Hirano Masao , Kuroda Hisanori , Morimoto Takashi 
Published: July 2006

Abstract
The title oxidation resulted in a selective formation of the corresponding carbonyl compounds in excellent yields under mild conditions.
Crystal Structure of 4,4′,5,5′-Tetrachloro-2,2′-bi-1,3-dioxolane
Authors: Huang Hsing Hua , Ogata Koreharu , Sakai Shin-ichiro , Sim Keng Yeow 
Published: July 2006

Abstract
The main product, A obtained from the interaction of concentrated sulfuric acid with trans-2,3-dichloro-1,4-dioxane has been shown by a single crystal X-ray structure analysis to be the trans–trans meso-stereoisomer of 4,4′, 5,5′-tetrachloro-2,2′-bi-1,3-dioxolane.
Electrochemical Reduction of Carbon Dioxide at Various Metal Electrodes in Aqueous Potassium Hydrogen Carbonate Solution
Authors: Noda Hidetomo , Ikeda Shoichiro , Oda Yoshiyuki , Imai Kazumoto , Maeda Masunobu , Ito Kaname 
Published: July 2006

Abstract
The electrochemical reduction of carbon dioxide at various metallic electrodes was carried out potentiostatically at 298 K in aqueous potassium hydrogen carbonate solution in order to make clear the electrocatalysis of metals in reduction of CO2. It was found that metals used as electrodes are classified into four groups according to their main products from CO2, i. e., metallic In, Sn, Hg, and Pb are selective for the production of formic acid; metallic Ag and Au are selective for the formation of carbon monoxide; metallic copper has the highest electrocatalytic activities in formation of hydrocarbons, aldehydes, and alcohols; and metallic Al, Ga, Group a, and Group VIII elements except Pd have scarce electrocatalytic activity in reduction of CO2. Effects of the reduction potential on products from CO2 were also examined in detail for Zn, In, and Au electrodes which have some interesting properties.