bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Dispersion in Carbon Monoxide Adsorption and Carbon Monoxide Hydrogenation over Alumina-supported Ruthenium Catalysts
Authors: Okuhara Toshio , Kimura Tomoo , Kobayashi Kenji , Misono Makoto , Yoneda Yukio 
Published: July 2006

Abstract
Ru/Al2O3 catalysts prepared from [Ru3(CO)12] and from RuCl3 were characterized by chemisorption of H2 and CO, and by infrared measurement of adsorbed CO. By using these catalysts, the effect of the dispersion on the activity and selectivity in CO hydrogenation was studied. Ru/Al2O3 catalysts prepared from [Ru3(CO)12] showed high dispersions (&gt;80%), and were more active and selective for the production of olefins in the CO hydrogenation than Ru/Al2O3 catalysts prepared from RuCl3. However, the distribution of product hydrocarbons was not sensitive to the Ru dispersion. Infrared study of adsorbed CO revealed that twin-type CO (Ru(CO)2) as well as linear-type CO (Ru–CO) was present on each Ru/Al2O3. The twin-type CO was more strongly held and was less reactive to hydrogenation. For each series of Ru/Al2O3, the turnover frequency increased as the dispersion decreased. This change has been explained by the poisoning effect of the twin-type CO. The higher activity of Ru/Al2O3(A) was ascribed to the lower concentration of the twin-type CO on the surface.
Optically Active and Racemic Glycerides. II. Thermodynamic Studies on the Polymorphic Transition of (R)- and (RS)-1,2-Diglycerides
Authors: Iwahashi Makio , Ashizawa Kazuhide , Ashizawa Miyuki , Kaneko Yoshihide , Muramatsu Mitsuo 
Published: July 2006

Abstract
The polymorphic relationship between optically active (R)- and for racemic (RS)-forms of 1,2-distearin and 1,2-dipalmitin were studied by X-ray diffraction, infrared spectrum, and the thermal analysis. These glycerides have two crystalline forms, α and β, wherein α is metastable and β is stable under ordinary conditions. The α→β transformation for the (RS)-1,2-distearin crystal was extremely slow as compared with that for the (R)-form crystal, implying that the β-form crystal of (RS)-1,2-distearin is an eutectic mixture of small (R)- and (S)-crystals while the α-form crystal of (RS)-1,2-distearin is composed of a replacement type solid solution of (R)- and (S)-1,2-distearin molecules. Almost the same results were obtained with 1,2-dipalmitin, for which the rate of α→β transformation is higher than that for the 1,2-distarin, probably because of a higher mobility of this compound.
The Use of N,N-Dimethylformamide–Sulfonyl Chloride Complex for the Preparation of Thiophenesulfonyl Chlorides
Authors: Sone Tyo , Abe Yukio , Sato Norio , Ebina Manabu 
Published: July 2006

Abstract
A 1:1 N,N-dimethylformamide–SO2Cl2 complex was found to be a useful agent for the one-step preparation of thiophenesulfonyl chlorides.
Temperature Effect on Transference Numbers for KCl in Ethanol–Water Mixtures
Authors: Ueno Masakatsu , I Sh\={o}go , Shimizu Kiyoshi 
Published: July 2006

Abstract
Cation-transference numbers were determined by the moving boundary method for 0.02 mol dm−3 KCl in 5-, 10-, 15-, 20-, and 30 mol% ethanol–water mixtures at 15 and 35 °C. The cation-transference number has a maximum around 10 mol% of ethanol at each temperature studied, and becomes larger with decreasing temperature in the solvent of the same composition. From the temperature dependence of the transference number, the differences in the activation energy of transport between K+ and Cl− ions were estimated, and it was found that the activation energy of the K+ ion is less than that of the Cl− ion and the difference becomes larger in the range of 5–20 mol% of ethanol. These results are discussed in terms of structural effects and ion-solvent interactions.
A New Calibration Method for the Measurement of CCl4 Concentration at 10−10 v/v Level and the Behavior of CCl4 in the Atmosphere
Authors: Yokohata Akihito , Makide Yoshihiro , Tominaga Takeshi 
Published: July 2006

Abstract
A new technique was developed for the accurate determination of atmospheric CCl4 at about 100 pptv (=10−10 v/v) concentration level, since at such extremely low concentration CCl4 was found to be adsorbed readily and strongly on clean metal surfaces under dry conditions. The analysis of CCl4 by gas chromatography/electron-capture detector and the preparation of CCl4 primary calibration standard were improved by introducing water vapor into the system to prevent the adsorption of CCl4 and to obtain stable and reproducible results. The total amount of CCl4 in the atmosphere was studied on the basis of our newly calibrated data of CCl4 concentration, and a reasonable lifetime of CCl4 was obtained assuming that its sink is only the UV photodissociation in the stratosphere.
Photoelectrochemical Reduction Products of Carbon Dioxide at Metal Coated p-GaP Photocathodes in Aqueous Electrolytes
Authors: Ikeda Shoichiro , Yoshida Makoto , Ito Kaname 
Published: July 2006

Abstract
In order to increase the current efficiency of the photoelectrochemical reduction of CO2 in aqueous electrolytes, metals such as Pb and Zn, which have a higher overpotential for the hydrogen evolution reaction, were coated on a p-GaP photocathode by sputtering and electroplating. Au was also coated by sputtering. Then, the photoelectrolytic experiments were carried out in a gas-tight cell with a cyclic gas-flow system. The products in a gas phase were determined as well as the products in the electrolyte. Accordingly, CO in addition to HCOOH as a reduction product of CO2 was found to be produced as well as substantial amount of H2 as a by-product. However, other products such as HCHO and CH3OH were not found at all. In the case of the Pb coated p-GaP electrode, the current (faradaic) efficiency, η, for HCOOH formation was increased up to 48.2%, although in the case of bare p-GaP it was only 4.8% at maximum. On the other hand, the η for CO formation at the Zn-coated p-GaP electrode went up to 16.5%. While, in the case of an Au-coated p-GaP, the η for the CO2 reduction was not so changed as for the bare p-GaP photocathode.
Amide Ion Formation and N-Alkylation of Aminoanthraquinones in the Presence of Potassium Hydroxide in Dimethyl Sulfoxide
Authors: Arai Sadao , Kato Seijiro , Hida Mitsuhiko 
Published: July 2006

Abstract
Amide ions were formed by the deprotonation of the amino group of amino- and (monoalkylamino)anthraquinones in the presence of powdered potassium hydroxide in dimethyl sulfoxide (DMSO). Under a nitrogen atmosphere these amide ions changed to their radical anions. The amide ions of 1-aminoanthraquinones reacted with excess alkyl halides to yield 1-alkylaminoanthraquinones, while the N-alkylation of 2-aminoanthraquinones afforded 2-dialkylaminoanthraquinones in good yields. 2-Aminobenzophenone underwent mono-N-alkylation, while 4-aminoazobenzene and p-nitroaniline underwent di-N-alkylation. It was also found that the carbanion of DMSO easily attacked the carbonyl group of the (dialkylamino)anthraquinones.
Synthetic Photochemistry. XXIX. A Convenient Preparation of 1,2,3-Substituted Cyclopentenes from the Photoadducts of Methyl 2,4-Dioxopentanoate–Isoprene
Authors: Kato Nobuo , Takeshita Hitoshi 
Published: July 2006

Abstract
Photoadducts obtained by cycloaddition of isoprene with methyl 2,4-dioxopentanoate were converted to cyclopentene derivatives. The stereochemistry of the intermediate glycols was estabilished by chemical correlations to each other; only the cis-glycols were convertible to the cyclopentenes under the conditions employed, suggesting a fore-going acetylation of the hindered glycol functions.
Synthesis of cis-transoid-cis- and cis-cisoid-cis-Tricyclo[6.3.0.02,6]undecan-1-ols
Authors: Kakiuchi Kiyomi , Takeuchi Hideyuki , Tobe Yoshito , Odaira Yoshinobu 
Published: July 2006

Abstract
Two isomeric linear triquinanes, cis-transoid-cis- and cis-cisoid-cis-tricyclo[6.3.0.02,6]undecan-1-ols, were effectively synthesized by means of the modified Barbier cyclization.
The Solution Chemistry of Organotin Compounds. III. A Thermodynamic Study of the Molecular Interaction of Me2SnCl2 with Lewis Bases by Means of Nuclear Magnetic Resonance Spectroscopy
Authors: Fujiwara Hideaki , Sakai Fumihiko , Mikawa Yoshihiro , Sasaki Yoshio 
Published: July 2006

Abstract
Molecular interaction of Me2SnCl2 with Lewis bases has been investigated by measuring the concentration and temperature dependence of NMR coupling constant 2J(119Sn,H). It is found that 1 : 1 and 1(acid):2(base) complexes are formed concurrently in solution. Association constants and coupling constants in these complexes are determined at different temperatures, leading to the enthalpies ΔH° and entropies ΔS° for the relevant molecular interaction. The coupling constants are temperature independent and a merit of using this constant as a diagnostic tool has been proven. The E and C parameter treatment of ΔH°AB has given reasonable EA and CA values for Me2SnCl2. Entropies ΔS° are also estimated in gas phase on the basis of molecular theory for the third-law entropy, and the contribution from solvation is shown important in the solution of CHCl2CHCl2.
Kinetics of Heterogeneous Photocatalytic Decomposition of Phenol over Anatase TiO2 Powder
Authors: Okamoto Ken-ichi , Yamamoto Yasunori , Tanaka Hiroki , Itaya Akira 
Published: July 2006

Abstract
The photocatalytic decomposition of phenol over anatase TiO2 powder followed the first-order kinetics, upto high conversions, of which the apparent rate constant kap depended on initial concentration of phenol [phenol]0, [TiO2], O2 pressure pO2, and incident light intensity I. The dependence of the initial reaction rate Ω0 on [phenol]0 showed characteristic curvature convex to the concentration axis. The pO2 dependence of both Ω0 and kap was very similar each other and showed characteristic curvature to the pO2 axis. The dependence of both Ω0 and kap on [phenol]0 was affected by the [TiO2] and I. Both Ω0 and kap were proportional to I below ca. 1×10−5 mol m−2 s−1 and to I1⁄2 above 2×10−5 mol m−2 s−1. The activation energy was 10 kJ/mol. The results were satisfactorily explained by the equation;
Ω=φ·OHIan\fracKO2pO21+KO2pO2·\frac[phenol][phenol]0+β,
where Ω is the reaction rate; φ·OHIan, a parameter related to the formation rate of ·OH radicals or real reactive species; KO2, the equilibrium constant of Langmuir adsorption of O2; β, the ratio of the combined first-order rate constant of the reaction of ·OH with species other than organic compounds to the second-order rate constant of the reaction of ·OH with phenol.
Formaldehyde Electro-oxidation on Copper Metal and Copper-based Amorphous Alloys in Alkaline Media
Authors: Machida Ken-ichi , Enyo Michio 
Published: July 2006

Abstract
Copper metal and copper-based amorphous alloys, a-Cu35Ti65 and a-Cu33Zr67, exhibit a very high and stable activity for the anodic HCHO oxidation in aqueous NaOH and Na2CO3. The oxidation current was already observable at electrode potentials as low as 0.1 V (RHE) and, in particular, the HF-treated amorphous alloys gave high current densities around 40 mA cm−2 (apparent) at 0.2 V. Kinetic data, roughly first order both in HCHO and OH− concentration, are in favour of the mechanism in which the oxidation proceeds via hydroxymethanolate ion (HOCH2O−) formed from HCHO and OH−, producing HCOO− and H2: This ion is readily oxidized on the copper metal or copper-based amorphous alloy electrodes. The Tafel slope was in general agreement with the reaction mechanism assuming a rate-determining one-electron transfer step.
Crystal Structure of 6-[6(e)-Carbamoyltetrahydro-2(e)-pyranyl]8-oxa-6-azabicyclo[3.2.1]octan-7-one
Authors: Yamane Takashi , Nanayama Hiroto , Ashida Tamaichi , Hashimoto Kazuhiko , Sumitomo Hiroshi 
Published: July 2006

Abstract
The structure of the dimerization product of bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.1] octan-7-one, was determined by the X-ray diffraction method. The final R value was 0.062 for 2009 reflections. The structure suggests that the cationic oligomerization of the bicyclic oxalactam proceeds through the C5–N6 scission, differing from the cases of other common lactams.
Photocatalytic Isomerization of Butenes over ZnO and SnO2
Authors: Kodama Sukeya , Yabuta Masaaki , Anpo Masakazu , Kubokawa Yutaka 
Published: July 2006

Abstract
It has been found with ZnO as well as TiO2 that 2-butene is much more reactive than 1-butene for their photocatalytic isomerization. Although both cis-trans and double bond isomerizations take place on ZnO, only cis-trans isomerization occurs over SnO2. The photocatalytic isomerizations were suppressed drastically in the presence of NO. From those results together with the ESR studies the following conclusions emerge: a butene molecule interacts with the photoformed O− to form a radical species as a result of fission of the C=C bond; the photocatalytic isomerization proceeds via such a radical intermediate; the lack of the reactivity of 1-butene appears to be explicable on such basis.
The Stereochemistry of the Six Geometrical Isomers of the Bis(ethylenediamine-N-acetato)cobalt(III) Ion, [Co(edma)2]
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji , Matsumoto Keiji , Ooi Shun’ichiro 
Published: July 2006

Abstract
All of the six geometrical isomers possible in [Co(edma)2]+ (edma: ethylenediamine-N-acetate) were isolated, and the five chiral isomers were resolved into optically active isomers by a column-chromatographic method. Their structures were determined on the basis of the X-ray analysis and the visible absorption, 1H NMR, and CD spectral data. One of the methylene protons in the glycinate-ring of the facially coordinating edma is stereospecifically exchanged by a deuteron in the basic D2O solution, and its deuteration rate is influenced by the ligating atoms in the trans position. A 1H NMR method to determine the absolute configurations of the optically active isomers, which contain the stereospecifically deuterated edma, is reported and applied to the [Co(edma)2]+ systems. The relationship between the absolute configurations and the CD spectral behaviors of these complexes is also discussed.
Conductometric and Potentiometric Studies of the Association of α-Cyclodextrin with Ionic Surfactants and Their Homologs
Authors: Satake Iwao , Ikenoue Tadashi , Takeshita Tokuro , Hayakawa Katumitu , Maeda Tamaki 
Published: July 2006

Abstract
The conductometric determination was made of the association constants of α-cyclodextrin (αCD) with ionic surfactants and their homologs. For 1-alkanesulfonate ions with carbon atoms (n) of 5–12, the association constant was found to increase regularly with n and become abruptly constant at n=10. The association constants for sodium 1-dodecanesulfonate, dodecylammonium chloride, dodecyltrimethylammonium chloride, and 1-dodecylpyridinium chloride were all similar in their magnitude. The effect of complexation on the micellar properties of sodium dodecyl sulfate and dodecyltrimethylammonium chloride were also studied potentiometrically by determining the counterion activities. In both cases, the critical micelle concentration increased regularly, while the degree of counterion association to the micelle decreased almost linearly with increasing αCD concentrations. It was suggested that the αCD-surfactant ion complex is solubilized in the hydrophilic surface region of surfactant micelle to give rise to a decrease in the surface charge density.
Reactions of NH Radicals. IV. Photolysis of HN3 in the Presence of CH4 at 313 nm
Authors: Kodama Sukeya 
Published: July 2006

Abstract
The photolysis of HN3 vapor in the presence of CH4 was studied at 313 nm, 30 °C, and a low light intensity. The reaction products were N2, H2, NH4N3, CH3NH2·HN3, and CH3N3. CH3 radicals were also detected as intermediates. The quantum yields of these products were measured as a function of the CH4 and HN3 pressures. The following mechanisms for the main reactions were proposed: HN3+hν(313nm)→N2+NH(a1Δ); NH(a1Δ)+HN3→2N2+2H(2a); NH(a1Δ)+HN3→N3+NH2 (2b); NH(a1Δ)+HN3→N2+N2H2* (2c); NH(a1Δ)+ CH4→CH3NH2* (3); NH(a1Δ)+CH4→NH(X3Σ−)+CH4 (4); CH3NH2*→H+CH2NH2 or CH3NH (5); CH3NH2*→CH3+NH2 (6). The rate-constant ratios at 30°C were: k3⁄k2=0.175; k4⁄k2=0.177; k6⁄k5=0.133. The collisional deactivation of CH3NH2* was not found in the total pressure range, from 6.4 to 24.3 kPa.
Formation and Reactions of 2-Substituted 4,4-Dimethyl-5(4H)-oxazolones. The 5(4H)-Oxazolone as a Stable Intermediate in Peptide Bond Formation
Authors: Narita Mitsuaki , Ishikawa Kazunori , Kudo Koji , Endo Takeshi 
Published: July 2006

Abstract
The reaction of Boc–Leu3–Aib–OH with H–Leu3–OBzl using DCC as a coupling reagent proceeded via the exclusive 2-substituted 4,4-dimethyl-5(4H)-oxazolone formation followed by a slow aminolysis. Similar treatment of Boc–Leu3–Aib–OH with DCC in the presence of p-nitrophenol did not produce a p-nitrophenyl ester, but produced the 2-substituted 4,4-dimethyl-5(4H)-oxazolone (1) in a high yield within 20 min. The high potential for the oxazolone formation of Boc–Leun–Aib–OH (n=3 and 4) is apparently attributed to the conformational effect of C-terminal Aib residues, namely, the restriction of the backbone dihedral angles φ and ψ of Aib residues. Ring-opening reactions of oxazolones with hydroxy compounds were easily monitored by following the disappearance of the intense oxazolone peak at 1820 cm−1. The oxazolone (1) reacted faster with HOSu than H–Leu3–OBzl, followed by the slow aminolysis of the succinimide ester produced. In contrast, HOBt did not react with the oxazolones derived from Boc–Leu3–Aib–OH (n=3 and 4), but strongly catalyzed the aminolysis of the oxazolones in dichloromethane to form peptide bonds in nearly quantitative yields. A little catalytic effect of acetic acid on the oxazolone aminolysis indicated that the oxazolone aminolysis in the presence of HOBt did not proceed through a simple acid catalytic pathway, but proceeded through a biphilic (electrophilic–nucleophilic) pathway.
Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic N-Ylides with Unsymmetrically Substituted Olefinic Dipolarophiles
Authors: Tsuge Otohiko , Kanemasa Shuji , Takenaka Shigeori 
Published: July 2006

Abstract
Regioselectivity and stereoselectivity of the cycloadditions of heteroaromatic N-ylides with unsymmetrically-substituted olefins such as methyl-substituted cis olefins, an acrylate, the related olefins, trans nitro olefins, and other trans olefins have been investigated. These cycloadditions are highly regioselective, while the stereoselectivity depends upon both the electronic and steric nature of substituents of the ylide and olefin. The 1-endo-2-exo cycloadducts of the anti form of ylides which have been formed as kinetically controlled products undergo the isomerization into either the 1-endo-2-exo cycloadducts of the syn ylides through a retro cycloaddition process or the 1-exo-2-endo cycloadducts of the syn ylides via betaine intermediates.
Synthetic Studies on the Validamycins. XII. Synthesis of Optically Active Valienamine and Validatol
Authors: Ogawa Seiichiro , Shibata Yasushi , Nose Taisuke , Suami Tetsuo 
Published: July 2006

Abstract
(+)-Valienamine and (+)-validatol have been totally synthesized as the peracetyl derivatives starting from a common synthetic intermediate, (1S)-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol.
The 1-Octanol/Water Partition Coefficient of Mercury
Authors: Okouchi Shoichi , Sasaki Sokichi 
Published: July 2006

Abstract
The 1-octanol/water partition coefficient of metallic mercury was measured as a useful parameter for predicting the environmental behavior or fate of mercury. The partition coefficient obtained was 4.15±0.20 at 298 K; it slightly decreased from 4.80 to 3.80 as the temperature rose from 278 to 308 K. The partition coefficient of metallic mercury is very low in comparison with those of such nonpolar organic compounds as benzene and tetrachloromethane. Therefore, it was found that metallic mercury has a tendency to be further concentrated in the atmosphere.
Reaction of Malonaldehyde with Nucleic Acid. II. Formation of Fluorescent Pyrimido[1,2-a]purin-10(3H)-one Mononucleotide
Authors: Seto Hiroshi , Takesue Tomoyuki , Ikemura Tadashi 
Published: July 2006

Abstract
The reaction of malonaldehyde under acidic conditions (pH 4.5) with guanosine 5′-monophosphate resulted in the formation of fluorescent 3-(β-d-ribofuranosyl)pyrimido[1,2-a]purin-10(3H)-one 5′-phosphate (3a). This adduct was also isolated from malonaldehyde-reacted RNA. The amount of 3a in the modified RNA was estimated to be 0.4 per cent by weight. The fluorescence spectrum of 3a (Ex max. 360 nm, Em max. 500 nm) was similar to that of guanine- and guanosine-malonaldehyde adducts which have the same type base structure. On the other hand, another type of fluorophore (Ex max. 390 nm, Em max. 460 nm) was also formed in the reaction of malonaldehyde with a nucleic acid polymer. Thus, at least two different types of fluorophores are present in malonaldehyde-reacted nucleic acid.
Total Synthesis of Antibiotic Althiomycin
Authors: Inami Kaoru , Shiba Tetsuo 
Published: July 2006

Abstract
Total Synthesis of antibiotic althiomycin has been achieved starting from d-cysteine. The imide bond between thiazoline and the pyrrolinone part was constructed by coupling reaction of sodium salt of pyrrolinone with cysteine active ester or by photoreaction with diketene. The hydroxymethyl group attached on the carbon adjacent to C-2 of the thiazoline ring, was introduced by aldol condensation posterior to the thiazoline ring formation. The thiazole part was introduced in a final step in whole process of the total synthesis of the antibiotic. The synthetic althiomycin was identical with the natural antibiotic in all respects.
Preparation of Polyoxa- and Dioxapolythia[n](1,1′)ruthenocenophanes and Their Metal Complexes
Authors: Habata Yoichi , Akabori Sadatoshi , Sato Masaru 
Published: July 2006

Abstract
Polyoxa- and dioxapolythia[n]ruthenocenophanes were prepared by the reaction of 1,1′-diacetoxyruthenocene with α-(2-bromoethyl)-ω-bromopoly(oxyethylene) in the presence of alkali metal hydroxides and by the reaction of 1,1′-bis(2-chloroethoxy)ruthenocene with dithiolate in the presence of sodium hydroxide, respectively. The extraction ability of their compounds was excellent for mercury(II) and thallium(I) ions. The ruthenocenophanes with oxygen atoms attached to the ruthenocene nucleus showed excellent extraction ability for a silver(I) ion, although the corresponding ferrocenophane analogs decomposed in similar reaction conditions. The ruthenocenophanes formed 1 : 1 complexes with mercury(II) and silver(I) ions. 1H-NMR, electronic, and IR spectral data of their complexes showed the presence of direct electronic interaction between the mercury(II) or silver(I) ion and the ruthenium atom of ruthenocenophanes.
Electrodeposition of Catalytically Active Cobalt Powder from Aqueous Sulfate Electrolytes
Authors: Abd El-Halim A M , Khalil Reda Mohamed 
Published: July 2006

Abstract
The electrodeposition of cobalt powder was investigated from aqueous sulfate solutions containing 0.0125–0.0500 CoSO4·7H2O (I), 0.23–1.00 (NH4)2SO4 (II), 0.1 H3BO3 and 0.07 mol dm−3 Na2SO4·10H2O. The effects of the bath composition, the pH, the deposition current density and the duration of electrolysis on the cathodic polarization and the efficiency of cobalt electrodeposition, as well as on the morphology and the catalytic activity (towards the decomposition of 0.4% H2O2 solution) of the as-deposited cobalt powders were discussed. X-Ray diffraction studies proved that cobalt powders were very pure and deposited in the hexagonal close-packed structure with the orientations (100), (002), and (101). Cobalt powder deposited with an efficiency of 32% and had a catalytic activity approaching 100% could be obtained from the above-mentioned bath formula containing 0.05 mol dm−3 (I) and 0.46 mol dm−3(II). The optimum operation conditions to achieve these characteristics were: pH 4.78, j=10A dm−2 and t=15 min.