bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Flotation of Cd2+ Ions in the Presence and Absence of Zn2+ Ions
Authors: Kobayashi Koichi , Shimizu Yoshiko , Sasaki Tsunetaka 
Published: July 2006

Abstract
The flotation of Cd2+ ions was investigated in the presence and absence of Zn2+ ions. It was found that the flotation efficiency of Cd2+ ions in the Cd2+–anionic surfactant system is markedly small in the presence of Zn2+ ions, but the flotation efficiency of Cd2+ ions in the Cd2+–bentonite–cationic surfactant system (adsorbing particle flotation) decreased only slightly in the presence of Zn2+ ions. The flotation efficiency in the latter case was further increased by the addition of 3 ppm of polyacrylamide. The doubling of the flotation reagents and time did not effectively increased the flotation efficiency of Cd2+ ions in the presence of Zn2+ ions, but the two-stage flotation did. It was confirmed that the adsorbing particle flotation of Cd2+ ions would be an excellent method in the presence of Zn2+ ions.
Direct Measurement of the Interaction Energy between Solids and Gases. VI. Calorimetric Studies on Acidic Properties of Solid Super Acids Prepared from Silica–Alumina
Authors: Taniguchi Hitofumi , Masuda Tatsuo , Tsutsumi Kazuo , Takahashi Hiroshi 
Published: July 2006

Abstract
Solid super acids were prepared by the reaction of gaseous antimony pentafluoride with silica–alumina and heats of adsorption of ammonia on their surfaces were measured. Solid super acids gave about 170 kJ/mol of an initial differential heat of adsorption and their adsorption energies were mainly distributed in the vicinity of 137 kJ/mol, while the initial differential heat of adsorption on original silica–alumina was about 150 kJ/mol and its adsorption energy was chiefly distributed in the vicinity of 117 kJ/mol. Therefore, it was shown that solid super acid had stronger, more homogeneous and much more acid sites than original silica–alumina.
Effect of Pressure on Mesomorphic Transitions in Cholesterol Esters of Unsaturated C18 Aliphatic Acids
Authors: Nakahara Masaru , Maeda Katsumi , Osugi Jiro 
Published: July 2006

Abstract
The smectic to cholesteric, cholesteric to isotropic liquid, and solid to isotropic liquid transitions in the following cholesterol esters are determined by an optical method as a function of pressure up to 1 kbar; cholesteryl oleate, cholesteryl linoleate, and cholesteryl linolenate. The pressure dependence of the transition temperatures (dT⁄dP) is in the range of 21 to 36 K kbar−1, and the volume changes (ΔV) computed by means of Clapeyron’s equation are between 0.42 and 1.3 cm3 mol−1 at 1 bar. The volume change for the smectic to cholesteric transition increases with the number of the double bonds in the acids, while that for the cholesteric to isotropic liquid is little affected by the double bonds.
Studies of the Ion Flotation by Poly(ethyleneimine) Resin
Authors: Sasaki Tsunetaka , Kurosawa Hisayo , Miyasaka Keiichi , Mizushima Minoru 
Published: July 2006

Abstract
Flotation of Crystal violet (CV+), neucoccin (NO−), CrO42−, PO43−, Fe3+, and Cu2+ ions was studied with use of poly(ethyleneimine) resin (PEI) as an adsorbent, Na-polyacrylate or polyacrylamide as a coagulant and sodium dodecyl sulfate or hexadecyltrimethylammonium chloride as a frother. In line with the results of adsorption studies, NC−, PO43−, and CrO42− ions were effectively floated from their dilute solutions but CV+ was not floated so much. The most effective flotation was attained for CrO42− ions, a rapid initial decrease in concentration due to the flotation within 30 s being followed by a gradual decrease and nearly 100% flotation achieved within 10 min for a dilute solution. The rate of flotation follows a bimolecular reaction. The activation energy of flotation, 28.03 kJ mol−1, is equal to that of CrO42− ion adsorption by PEI. Flotation of Fe3+ and Cu2+ ions was effectively carried out through chelate formation of these ions with PEI.
12,13-Epoxy-C-nor-D-homosteroids. VII. Reaction of 11-Oxygenated 17α-Acetyl-12β,13β-epoxy-13-epietiojervanes with Boron Trifluoride Etherate and Potassium Hydroxide
Authors: Murai Akio , Sasamori Hiroshi , Masamune Tadashi 
Published: July 2006

Abstract
The title compounds were treated with boron trifluoride etherate in benzene at room temperature. 11β-Hydroxy- and 11-oxo-12β,13β-epoxides (1 and 14) underwent cleavage of the epoxy group at C-13 by the acid treatment to give the corresponding fluorohydrins (2 and 5) as the respective major products, while the former (1) also afforded a 13β-pregnane derivative (3) with a normal steroid skeleton. On the other hand, several 11-oxygenated 12α, 13α- and 12β,13β-epoxides (17, 17a, 19, 21, 1, and 23) were treated with potassium hydroxide in aqueous methanol at room temperature. All epoxides gave the corresponding Δ13(17)-20-ketones, and only 11-hydroxy- and 11-acetoxy-12α,13α-epoxides (17, 19, and 17a) were further transformed into a 13α-pregnane derivative (12).
Syntheses and Characterization of Some New (3-Oxo-1-cyclohexenyl) palladium(II) Complexes
Authors: Onishi Masayoshi , Yamamoto Hideharu , Hiraki Katsuma 
Published: July 2006

Abstract
trans-Chloro(3-oxo-1-cyclohexenyl)bis(triphenylphosphine)palladium(II) (1) reacted with 1,2-bis(diphenylphosphino)ethane (dppe), 1,10-phenanthroline (phen), sodium diethyldithiocarbamate–water (1/3), and sodium tetra(1-pyrazolyl)borate {Na[BPZ4]} (Pz=1-pyrazolyl) to give the corresponding new (3-oxo-1-cyclohexenyl)palladium(II) complexes, [Pd(oxch)Cl(dppe)] (oxch=3-oxo-1-cyclohexenyl) (2), [Pd(oxch)Cl(phen)], [Pd(oxch)(S2CNEt2)(PPh3)], and [Pd(oxch)(BPZ4)(PPh3)], respectively. Complex 2 was treated with carbanions derived from methyl and ethyl cyanoacetates and malononitrile, and new diorganopalladium(II) complexes were obtained. These complexes were characterized by means of elemental analyses and IR and 1H-NMR spectroscopy. The stereochemical nonrigidity of the BPZ4 complex was discussed.
Use of the Copper(II) Ion-selective Electrode for the Determination of the Stability Constant of Binuclear Copper(II) Complex with 3,6-Dioxaoctane-1,8-diamine-N,N,N′,N′-tetraacetric Acid
Authors: Ohzeki Kunio , Saruhashi Masakuni , Kambara Tomihito 
Published: July 2006

Abstract
The stability constant of binuclear copper(II) complex with 3,6-Dioxaoctane-1,8-diamine-N,N,N′,N′-tetraacetric acetic acid (ethylene glycol bis[2-[bis(carboxymethyl)amino] ethyl] ether, customarily abbreviated to EGTA of Y) was determined on the basis of potentiometric titration by means of a copper(II) ion-selective electrode. In acetate buffer solution of pH 5.8 titration curves of copper(II) with EGTA show two distinct end points corresponding to Cu2Y and CuY complexes. The formation constant of the binuclear copper(II) complex was determined from the potential response in the titration fraction between first and second end points. The logarithmic value was found to be log KCu2Y=6.40 at ionic strength of 0.2 M (KNO3–acetate buffer solution) at 25±0.5 °C.
Studies of Unusual Amino Acids and Their Peptides. XII. The Chemistry of N-(Carboxymethyl)amino Acids. I. The Preparation, Properties, and Characterization of N-(Carboxymethyl)amino Acids and Their Esters
Authors: Miyazawa Toshifumi 
Published: July 2006

Abstract
N-Carboxymethyl(Cm-)amino acids and their mono- and diesters were prepared by several routes, and their physical and chiroptical properties were compared with those of the parent amino acids and their esters. The isolation procedure was improved for the preparation of the free Cm-amino acids obtained from the corresponding amino acids and bromoacetic acid; the aimed-at compounds were also obtained by the catalytic hydrogenolysis of the dibenzyl esters. The isomeric pairs of monoalkyl esters of Cm-amino acids were similarly accessible via the benzyl alkyl esters. The diesters proved to be suitable for the GLC and MS analyses of Cm-amino acids. All the free Cm-l-amino acids and the dicyclohexylammonium salts of their N-ethylthiocarbonothioyl derivatives show positive Cotton effects at 200–225 nm and at 335–350 nm respectively in CD measurements; therefore, these correlations can be used for the configurational assignments of Cm-amino acids.
Reactions of Substituted Epoxides with Alkyl Chloroacetate
Authors: Takeda Tokuji , Yasuhara Satoshi , Watanabe Shoji 
Published: July 2006

Abstract
The reactions of substituted epoxides with alkyl chloroacetate in the presence of lithium salts, quarternary salts and zinc chloride were studied. The reaction of 1-chloro-2,3-epoxypropane (1a) with butyl chloroacetate (BCA) in the presence of any of these catalysts yielded exclusively butyl [2-chloro-1-(chloromethyl)ethoxy]acetate (2a) via the normal cleavage of 1a followed by the reaction with the chloroacetate. On the other hand, the reaction of 1,2-epoxypropane(1b) with BCA yielded a mixture of isomeric products resulting from the normal and abnormal cleavages of 1b, and the ratio of the normal and abnormal products is dependent on the type of the catalyst. Moreover, it was found that lithium salt alone catalyzed the insertion reaction in a polar aprotic solvent, whereas the reaction in aromatic solvent needed a suitable co-catalyst such as hexamethylphosphoric triamide and triphenylphosphine oxide.
A New Synthesis of Glutathione via the Thiazoline Peptide
Authors: Ozawa Yoichi , Tsuji Toshiaki , Ariyoshi Yasuo 
Published: July 2006

Abstract
A convenient synthesis of glutathione (GSH) by the use of minimal protecting groups was investigated. N-Formyl-l-2-amino-4-cyanobutyric acid ethyl ester was condensed with ethyl l-cysteinylglycinate to give (4R)-2-[(3S)-3-ethoxycarbonyl-3-(formylamino)propyl]-4-(ethoxycarbonylmethylcarbamoyl)-2-thiazoline. This compound was saponified in aqueous acetone at −15–−20 °C and subsequently treated with dilute H2SO4 (pH 4) to yield formylglutathione, whose formyl group was then hydrolyzed with 0.5 M (1 M=1 mol dm−3) H2SO4 to give free GSH. For purification, this was changed to a copper thiolate, which was then decomposed with H2S to afford pure GSH.
Electron Transfer Sensitization. III. A Kinetic Study of Oxidative Dye Formation from Leuco Crystal Violet
Authors: Kitamura Noboru , Tazuke Shigeo 
Published: July 2006

Abstract
The action of electron transfer sensitization was quantitatively discussed by measuring photooxidative dye formation of leuco Crystal Violet (LCV) in the perylene (Pe)-1,4-dicyanobenzene(DCB)–LCV combination in polar media. Under the conditions of exclusive photoexcitation of perylene (λex at 435 nm), the kinetic study revealed that the turn over number of perylene as a sensitizer was immeasurably large in the ternary system in vacuo. This is an indication that perylene is indeed recycled via two successive electron transfer processes. The turn over number decreased to 58 in air, probably due to instability of intermediate ion radicals. The quantum yield was larger for the ternary system than for the binary system(Pe–LCV) irradiated at 435 nm. Although the absolute quantum yield of photooxidation was in the order of 10−3 or less in both systems, the ternary electron transfer system was apparently advantageous since the efficiency of back electron transfer would be reduced when multiple electron transfer processes are linked. Furthermore, the concept of electron transfer sensitization enables spectral sensitization and utilization of low energy photons in singlet state photoredox reactions. Such systems would be considered as a model for the primary action of photosynthesis.
Spherical Particles and Their Surface Properties. I. Interaction of Water with the Surface of Spherical Silica
Authors: Morimoto Tetsuo , Kadota Toshie , Yanazawa Hiroshi , Kittaka Shigeharu 
Published: July 2006

Abstract
Spherical particles of silica were prepared by passing fine silica material through the O2–H2 flame. Spherical particles obtained were amorphous, creviceless, and very large in size compared to those of the starting material which indicates that spheres are made by complete comelting of a large number of fine particles. Water adsorption measurements showed that the rate of rehydration of the dehydroxylated silica surface is very slow, especially at low water pressures, and that the spherical silica has a heterogeneous surface, this heterogeneity being enhanced when the sample is heated at elevated temperatures. The ratio of the number of water molecules adsorbed in the first physisorption layer to that of the underlying surface hydroxyls was found to be 1:1.
Studies of Polyphenyls and Polyphenylenes. II. The Synthesis and Physical Properties of Polyphenyls Containing Para Linkage
Authors: Ozasa Shigeru , Hatada Noriko , Fujioka Yasuhiro , Ibuki Eiichi 
Published: July 2006

Abstract
Twelve linear polyphenyls, including quinque- to octiphenyl, were synthesized by the Ullmann cross-coupling reaction of iodobiphenyl with diiodobenzene or iodoterphenyl. Ultraviolet spectral studies of the polyphenyls indicated that the positions of the K-bands above ca. 260 nm, regardless of the presence of o- or m-phenylene unit(s), may be considered to be an indication of the approximate number of consecutive p-phenylene units. Infrared studies also showed that the locations of strong or medium bands in the 815–850 cm−1 region may give the same information. The HMO calculations of the longest wavelength absorption bands of twenty-four polyphenyls were carried out. A comparison between the calculated and observed wavelengths gave rather good agreement, except in the cases of two compounds. The signals of the proton magnetic resonance spectra of eighteen polyphenyls were assigned tentatively. The correlations between the arrangement of the benzene rings and the spectral patterns are discussed.
Synthesis of 2,5-Dehydrohomoadamantane (Tetracyclo[5.3.1.02,5.03,9]undecane) from 2,4-Dehydrohomoadamantane (Tetracyclo[5,3.1.03,5.04,9]undecane)
Authors: Katsushima Takeo , Yoshikawa Masato , Yamagughi Ryohei , Kawanisi Mituyosi 
Published: July 2006

Abstract
A reaction of 2,4-dehydrohomoadamantane with NBS in AcOH followed by LiAlH4 reduction and subsequent CrO3–pyridine complex oxidation gave endo-2-bromohomoadamantan-4-one (9) in good yield. A treatment of 9 with t-BuOK in t-BuOH followed by Wolff-Kishner reduction furnished 2,5-dehydrohomoadamantane.
Photo- and Thermally-induced Radical Rearrangements of Hypoiodites of 3α- and 3β-Methyl-5-cholesten-3-ols in the Presence of Mercury(II) Oxide and Iodine or Silver(II) Oxide and Iodine
Authors: Suginome Hiroshi , Maeda Norio 
Published: July 2006

Abstract
Hypoiodites of 3α- and 3β-methyl-5-cholesten-3-ols in benzene containing mercury(II) oxide and iodine gave 3α,5-epoxy-6β-iodo-3β-methyl-A-homo-4-oxa-5α-cholestane in 50–66% yield on irradiation or heating in the dark. Some minor products including the 6α-epimer were also found. The corresponding reaction with silver oxide and iodine reagent gave the same epoxide in 52% yield, together with a low yield of 3,4-seco-3-methyl-3-oxo-5-cholesten-4-al. Hydrogenolysis of the 6β-iodide with Pd–C as a catalyst gave 3α,5-epoxy-3β-methyl-A-homo-4-oxa-5α-cholestane (52% yield), together with the 6α-epimer arising from isomerization. The former, on treatment with boron trifluoride etherate and acetic anhydride in benzene, was transformed into 2-acetyl-3-methyl-5-acetoxymethyl-4-oxa-5β-cholestan-2-one. This was converted into 2β-acetyl-3α,5-epoxy-3β-methyl-4-oxa-A-homo-5α-cholestane by the treatment with aqueous methanolic potassium hydroxide.
The Catalytic Reactions on Hafnium Dioxide
Authors: Onishi Yoshito , Iizuka Yasuo , Hamamura Takuya 
Published: July 2006

Abstract
The mechanisms of the catalytic oxidations of carbon monoxide and hydrogen on hafnium dioxide are similar to those on titanium dioxide (anatase and rutile) and zirconium dioxide, and the activation energies of these reactions have been correlated with the oxygen bond energies of these four oxides.
The Reaction of 3-Hydroxyflavones with Metal Salts
Authors: Hamado Mutsumi , Kurosawa Kazu 
Published: July 2006

Abstract
The reaction of 3-hydroxyflavones (1a–d) with lead(IV) acetate gave 1,2-diphenylethanediones (2a–d), 1,2-diphenyl-2-hydroxyethanones, 2-hydroxybenzoic acids (7 and 9), and benzoic acids (8 and 10), and the reaction with manganese(III) acetate yielded 2, 7, 8, 9, and 10. In addition to 2, 7, and 10, 6-methoxy-2-(4-methoxybenzoyloxy)-3(2H)-benzofuranone and 2-hydroxy-4-methoxybenzaldehyde were obtained in the reaction of 1c with manganese(III) acetate. It has been established by the studies of 14C-labelled compounds that the C(3) in the 3-hydroxyflavone was lost during the reaction.
Reduction by a Model of NAD(P)H. 27. Role of Bivalent Metal Ion in the Reduction of 2-Acylpyridines and 1-Acylisoquinolines
Authors: Ohno Atsuyoshi , Yasui Shinro , Oka Shinzaburo 
Published: July 2006

Abstract
Reductions of 1-acetylisoquinoline (AQ), 1-benzoylisoquinoline (BQ), and isoquinoline-1-carbaldehyde have been studied kinetically and the results are compared with those of 2-acetylpyridine (AP), 2-benzoylpyridine (BP), and pyridine-2-carbaldehyde. Equilibrium constants for complexes between these substrates and zinc ion have also been studied. Kinetic deuterium isotope effects for AQ and BQ are smaller than the corresponding product isotope effects, respectively, whereas those for AP and BP are identical. The results are discussed in terms of stability and reactivity of intermediate radical-ion pair, and it is concluded that strong coordination of a metal ion onto the reaction site of a substrate facilitates the complexation but interferes the reduction.
The Synthesis and Decomposition of Calcium Tetraphosphate
Authors: Watanabe Makoto , Suzumori Hiroyasu , Maeda Mioko , Yamada Tamotsu 
Published: July 2006

Abstract
Calcium tetraphosphate was made by hydrolyzing cyclotetraphosphate in a 5-mol dm−3-solution of sodium hydroxide, neutralizing the phosphate solution with 1 mol dm−3 hydrochloric acid, and then adding calcium chloride to the solution. The P/Ca molar ratio of the product was 1.4–1.5. The tetraphosphate was an amorphous substance containing 20–30% of water and was decomposed to phosphates with a shorter chain length with bound water at room temperature or at a higher temperature. Upon decomposition at 300 °C, the main product at the early stage was pyrophosphate. The hydrolysis of the tetraphosphate obeyed the first-order kinetics with respect to the concentration of the phosphate, and the activation energy of the hydrolysis was 105 kJ mol−1 at pH 3.5.
Studies on Diazo Type Process. VII. Electronic Spectra of 2-(Substituted phenylazo)-1-naphthol-4-sulfonic Acid
Authors: Suzuki Shin , Das Rebati C , Harada Kieko , Stoyanov Stefan 
Published: July 2006

Abstract
The absorption of 2-(substituted phenylazo)-1-naphthol-4-sulfonic acid has been studied in neutral, acidic, and alkaline aqueous solutions as well as in solid state. Assignment of band positions to azo and hydrazone tautomers has been made by calculations using the SCF-CI-MO method. Introduction of electron-donating (or electron-withdrawing) substituent in the diazo part showed bathochromic (or hypsochromic) shift of the absorption band, which was elucidated by the charge migration and the character of the substituents taking into account azo-hydrazone tautomerism. In case of compounds containing electron-donating substituents, aggregation seems to take place in the solid state.
On the Nature of the 5,10-Dimethyl-5,10-dihydrophenazine–Tetracyanoquinodimethane
Authors: Fujita Isao , Matsunaga Yoshio 
Published: July 2006

Abstract
The 5,10-dimethyl-5,10-dihydrophenazine–tetracyanoquinodimethane appears to be largely ionic at room temperature. The results of various physical measurements of this compound can be explained without the reversible nonionic-to-ionic transition proposed by Soos et al.
Thermal Rearrangements of 1,5-Dimethyl- and 1,3,5-Trimethyl-8-vinyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-ol and Their Alkoxides
Authors: Nitta Makoto , Komatsu Nobuo , Kasahara Ichiro 
Published: July 2006

Abstract
The reactions of 1,5-dimethyl- and 1,3,5-trimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one with vinylmagnesium bromide at 0 °C afforded 1,5-dimethyl- and 1,3,5-trimethyl-8-vinyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-ol, respectively. The thermal rearrangements of IIa,b and their alkoxybromomagnesium afforded 1,5-dimethyl or 1,3,5-trimethylbenzocyclohepten-6-one. It is suggested that the pathways involve an oxy-Cope rearrangement and the subsequent hydrogen migrations.
ESR Studies of a New Stable π-Conjugated 4,4′-(Biphenyl-3,3′-diyl)bis(aryloxyl) Biradical
Authors: Mukai Kazuo , Inagaki Noriko 
Published: July 2006

Abstract
ENDOR observations were carried out for 2,6-di-t-butyl-4-phenylphenoxyl and some of its derivatives. Based on the proton hyperfine splittings, the structure of the aryloxyl monoradicals was investigated in terms of the McLachlan MO calculation. A new stable π-conjugated bis(aryloxyl) biradical, 4,4′-(biphenyl-3,3′-diyl)bis(2,6-di-t-butylphenoxyl), was prepared, and the g- and D-tensor values of the biradical in toluene have been determined from its asymmetric frozen ESR spectrum. The D-tensor values were calculated for the twisted “cis” and “trans” conformers of the biradical molecule, using the McLachlan spin densities of 2,6-di-t-butyl-4-phenylphenoxyl, which is a monoradical half of the biradical.
Electron Spin Resonance Spectra of Square Planar Cobalt(II) Complexes with Various N4-Macrocyclic Ligands
Authors: Nishida Yuzo , Hayashida Kazuki , Sumita Akira , Kida Sigeo 
Published: July 2006

Abstract
ESR spectra of square planar cobalt(II) complexes with various N4-macrocyclic ligands were measured, the results being discussed in relation to the π-basicity and π-conjugation of the macrocyclic ligands.
Selective cis-Isomerization of 1-Pentene Catalyzed by Ni(I)-Triphenylphosphine Complexes
Authors: Kanai Hiroyoshi , Kushi Kenji , Sakanoue Kei , Kishimoto Nobuji 
Published: July 2006

Abstract
Selective cis-isomerization of 1-pentene was carried out by NiX(PPh3)3 (X=halogen and pseudohalogen). First-order plots were obtained except for the iodo-complex. The addition of tin(II) chloride increased both activities and ratios of cis-2-pentene to the trans-isomer. Protic solvents accelerated the isomerization. Isotopic exchange between C2D4 and C2H4 or 1-pentene reveals that a metal hydride addition-elimination mechanism is operative.
Calorimetric Study on Orientationally Disordered Crystals. Cyclohexene Oxide and Cyclohexanone
Authors: Nakamura Nobuo , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
Low-temperature calorimetric quantities were determined for cyclohexene oxide and cyclohexanone in the temperature range between 13 and 300 K. Molar heat capacity at saturation pressure of the condensed phases, transition and melting temperatures, and enthalpies of transition and melting were measured by an on-line automated adiabatic calorimeter with intermittent heating mode. Purities of both calorimetric specimens were determined from their melting behavior. The following thermodynamic quantities, CS°, SS°, [HS°(T)−HS°(0)]/T, and −[GS°(T)−HS°(0)]/T were tabulated at selected temperatures. The entropies of melting of both compounds were compared with those of cyclohexanol and cyclohexane. A factor affecting the entropy of melting was discussed from the viewpoint of non-globularity of the constituting molecules. The discussion was extended to the thermal stability of a number of orientationally disordered crystals so far studied.