bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamics of Steady States: “Resistance Change” Transitions in Steady-state Systems
Authors: Tykodi R J 
Published: July 2006

Abstract
Some one-current steady-state systems showing a discontinuous change in flow resistance at a point of instability—forced vaporization of carbon tetrachloride, Bénard instability in a horizontal layer of fluid heated from below, Taylor instability in the Couette flow of a liquid between coaxial rotating cylinders—are analyzed from a thermodynamic point of view: the behavior of the rate of entropy production and of the local potential (thermokinetic potential) for the system at the point of instability is explored. A multi-current situation involving a flip-flop current vs. voltage relation for the flow of electric current across a porous charged membrane is also commented on briefly.
Studies of the Metal Complexes of Cyclohexane Derivatives. V. Copper(II) and Nickel(II) Complexes of cis-1,3-Cyclohexanediamine
Authors: Saito Reiko , Kidani Yoshinori 
Published: July 2006

Abstract
A series of 1,3-chxn(cis-1,3-cyclohexanediamine) copper(II) and nickel(II) complexes have been prepared and studied using spectroscopic and magnetic techniques. The violet and red copper(II) complexes of 1,3-chxn were found to consist of monomeric distorted octahedra and slightly distorted square planers, respectively. The nickel(II) complexes have a square planar structure. The conformational change of the ligand from diequatorial to diaxial on coordination has been confirmed by infrared analysis.
Temperature and Composition Dependences of Transport Processes in Glass-forming Molten Mixtures of Zn(NO3)2·6.27H2O and CoCl2
Authors: Islam Nurul , Singh Kunwar Pal , Kumar Satendra 
Published: July 2006

Abstract
Density, viscosity, and electrical conductivity of glass-forming mixtures of zinc nitrate hexahydrate and anhydrous cobalt chloride were measured as functions of temperature and concentration. Non-Arrhenius temperature dependence of equivalent conductance, Λ and fluidity, φ has been discussed in terms of a three parameter equation derived from Adam-Gibbs model. A linear correlation has been obtained between the preexponential parameter, AY and the ideal glass transition temperature, T0. The composition dependence of Λ and φ has been described by the expression derived from the Adam-Gibbs equation on the criteria of constant T/T0, where T is the absolute temperature, and a modification to this expression has been made. An attempt has been made to describe the concentration dependence of Λη product in terms of modified Adam-Gibbs equation.
Solvent Extraction and Spectrophotometric Determination of Palladium with 3-(2-Hydroxy-5-methylphenyl)-5-(p-methoxyphenyl)isoxazoline
Authors: Deshmukh B K , Kharat R B 
Published: July 2006

Abstract
3-(2-Hydroxy-5-methylphenyl)-5-(p-methoxyphenyl)isoxazoline (HMPAO) is used for the simultaneous extraction and direct photometric determination of palladium. About 46 μg of palladium was quantitatively extracted at pH 1.0—2.0 with 10 ml of 1.0×10−3M HMPAO in isobutyl alcohol as a yellowish complex. It was measured spectrophotometrically at 332 nm, The system conformed to Beer’s law over the concentration range 1.0—20.0 μg of palladium per ml. The colour of the complex was stable for more than 48 h. Palladium was extracted quantitatively and was determined in the presence of large excess of ions which are associated with it. The extractable species was 1:2 (Pd: HMPAO) in nature. The equilibrium constants were determined according to the methods of Yatsimirskii and Leden with suitable modification.
Extraction-Spectrophotometric Determination of Vanadium(V) Employing N1-Hydroxy-N1,N2-diarylbenzamidines and Various Adduct-forming Substances
Authors: Patel K S , Mishra R K 
Published: July 2006

Abstract
The reactions of 16 newly synthesized N1-hydroxy-N1,N2-diarylbenzamidines with vanadium(V) in presence of various adduct-forming substances have been investigated photometrically in chloroform. The present study indicated the formation of 1:2:1 metal:reagent:acetic acid or phenol and 1:2:2 metal:reagent:thiocyanate complexes. On the basis of strong synergism, which is attributed to mixed-complex formation, simple, rapid, sensitive and selective methods for the spectrophotometric determination of microgram quantities of vanadium(V) have been developed. The influence of experimental variables on the procedures have been discussed.
Quaternisation at an Sp2 Nitrogen. II. An Analysis on the Substituent Effect and on the Nature of the Transition State
Authors: Behera G B , Sharma A 
Published: July 2006

Abstract
The kinetics of N-phenacylation of a number of substituted thiazoles and substituted phenacyl bromides have been investigated in nitrobenzene and in a number of other dipolar aprotic solvents. The rate constants of 2-amino-4-phenylthiazoles and 2-aminobenzothiazoles have been calculated with suitably developed equations. The deviation of the observed values from the calculated results has been ascribed to the steric effect. A seven membered hydrogen bonded transition state has been proposed on the basis of the results obtained from the substituent and medium effect.
Synthetic Studies on Terpenoids. I. Stereocontrolled Synthesis of (±)-1,2,3,4,4a,9,10,10a-Octahydro-7-methoxy-1,4a-dimethyl-10-oxophenanthrene-1β-carboxylic Acid: A Potential Intermediate for Diterpenoid Synthesis
Authors: Banerjee Ajoy K , Ceballo Carmen D , Vallejo Maria N , Bolivar Edith H 
Published: July 2006

Abstract
A stereocontrolled synthetic route to (±)-1,2,3,4,4a,9,10,10a-octahydro-7-methoxy-1,4a-dimethyl-10-oxophenanthrene-1β-carboxylic acid and its conversion to 1,2,3,4,4a,4b,5,6,7,9,10,10a-dodecahydro-10β-hydroxy-1,4a-dimethyl-7-oxophenanthrene-1β-carboxylic acid is described.
Oxidation of 2,6-Dialkyl-p-cresols by Metal Acetates
Authors: Itahara Toshio , Sakakibara Tsutomu 
Published: July 2006

Abstract
The oxidation of 2,6-dialkyl-p-cresols by silver(I) and palladium(II) acetate afforded the corresponding p-hydroxybenzyl acetates and p-hydroxybenzaldehydes.
Synthesis and Magnetic Behavior of Three Novel Di-μ-halobis[halo(1,2-benzoquinonedioxime)copper(II)] Complexes. Ferromagnetic Exchange Coupling
Authors: Mégnamisi-Bélombé Michel 
Published: July 2006

Abstract
Variable-temperature magnetic susceptibilities measured from 4.2 to 300 K on the new dimeric clusters indicate ferromagnetic exchange coupling with J=+4.63 cm−1 and J=+0.14 cm−1 for di-μ-bromobis[bromo-(4-chloro-1 ,2-benzoquinonedioxime)copper(II)] and di-μ-chlorobis[chloro-1,2-benzoquinonedioxime)copper(II)], respectively, and antiferromagnetic exchange coupling with J=–0.11 cm−1 for di-μ-bromobis [bromo(1,2-benzoquinonedioxime)copper(II)].
Synthesis and Redaction of 3-Bromoflavanones
Authors: Reddy N J , Sharma T C 
Published: July 2006

Abstract
Bromination of flavanone, 6-methylflavanone, 6-methyl-4′-methoxyflavanone, and 6-methyl-3′,4′-dimethoxyflavanone with pyridinium tribromide in glacial acetic acid gives the corresponding 3-bromoflavanones, which when refluxed with thiourea in ethanol undergo reduction to flavanones.
NMR Studies on Molecular Interactions Involved in Alkali Metal Halide–Amide–Glycol Ternary Systems
Authors: Hamaguchi Naoru , Nakagawa Terumichi , Uno Toyozo 
Published: July 2006

Abstract
Interactions in a ternary solution of alkali metal halide–amide–glycol have been investigated on the basis of NMR measurement of chemical shifts of OH proton of glycol and amidic protons of acetamide. Measurements were carried out with various alkali metal halides (MX, M=Li, Na, K, X=Cl, Br, I) and glycols (mono-, di-, tri-, and tetraethylene glycol). The dependency of the chemical shifts on solute concentration was examined with a ternary solution of potassium iodide–acetamide–ethylene glycol. The addition of alkali metal halide to respective glycols or glycolic solutions of acetamide gave rise to a change in chemical shift values. The observed changes were related to the ionic sizes of cations and anions of alkali metal halides and to the number of oxyethylene units in a glycol molecule. It was found that a large ion induces a higher magnetic field shift of resonance positions of glycolic OH proton and amidic proton at trans position than a small ion, the magnitude of the shift change being almost proportional to the concentration of ion, and halogen anion formed in glycolic solution tending to interact with hydrogen at trans position rather than at cis position. From a comparison with the values for chemical shifts of water proton in aqueous alkali metal halide solution, it is suggested that the contribution of alkali metal halide to the chemical shift changes in glycolic solution is similar to those in aqueous solution.
Determination of Magnetic Susceptibilities of Paramagnetic Gases by an Improved Viscometer Method
Authors: Sueoka Kazuo , Ikeda Toshio 
Published: July 2006

Abstract
An improved viscometer method has been applied to the determination of the magnetic susceptibility of a paramagnetic gas and found to be of use in the analysis of a paramagnetic gas mixed in a diamagnetic gas. The magnetic susceptibilities of oxygen and nitrogen monoxide have been determined to within ±0.5% using a saturated aqueous solution of sodium chloride as the working liquid.
Miexd Monolayers of Long Normal Chain Fatty Acids with Long Normal Chain Esters. I. Fatty Acids–Ethyl Hexadecanoate System
Authors: Matuo Hirosi , Yosida Noriaki , Motomura Kinsi , Matuura Ryohei 
Published: July 2006

Abstract
Surface pressure-area(π-A) curves of the two-component surface films of long normal chain fatty acids with ethyl hexadecanoate were measured at various compositions and temperatures. It was found that the π-A curves of the mixed monolayers vary characteristically with the number of carbon atoms of the film-forming acid. The two-dimensional phase diagrams of these systems and their partial molar enthalpy changes were obtained by taking advantage of the thermodynamic treatment of multicomponent surface films. It was concluded that the chain length of the acid plays an important role in the thermodynamic state of the mixed monolayer.
Phase Transition and Electronic States of Solid Ion Radical Salts
Authors: Iida Yôichi 
Published: July 2006

Abstract
Such crystalline ion radical salts as Würster’s Blue perchlorate and K+ p-Chloranil\ewdot are known to undergo phase transitions in the solid state. There are distinct differences in their optical and magnetic properties between the low- and high-temperature phases. Using Hubbard Hamiltonian, the electronic states of the high-temperature phases of those solid ion radical salts were explained in terms of an infinite non-alternant linear chain model, while those of the low-temperature phases, in terms of a dimer model.
Delayed Excimer Fluorescence of Acridine Orange Bound to DNA
Authors: Motoda Yuko , Kubota Yukio 
Published: July 2006

Abstract
The temperature dependence of long-lived emissions of Acridine Orange bound to DNA has been investigated. Only phosphorescence with a maximum close to 620 nm is observed in the range 77—ca. 150 K. With a rise in temperature, the delayed thermal fluorescence around 530 nm is observed in addition to phosphorescence at a high ratio of DNA phosphate to dye (P⁄D). With a decrease in P⁄D value, the delayed thermal fluorescence is replaced by a new delayed emission band around 640 nm. Its maximum wavelength is very close to that of dimer fluorescence of Acridine Orange in water. It has been shown that the emission results from two processes: (1) thermal excitation of the triplet state of the dimer to the excimer state and (2) excimer formation after the thermal excitation of the triplet state of the monomer to the first excited singlet state.
Preparation and Resolution of a Series of Chromium(III) Complexes Containing 2,2′-Bipyridyl N,N′-Dioxide and Ethylenediamine
Authors: Kanno Hideaki , Kashiwabara Kazuo , Fujita Junnosuke 
Published: July 2006

Abstract
A series of chromium(III) complexes of the type, [Cr(bpdo)n(en)3−n]3+ was obtained by preparing two new complexes, n=1 and 2, where bpdo denotes 2,2′-bipyridyl N,N′-dioxide. Each of the bpdo complexes gave only one pair of enantiomers, which were resolved by an SP-Sephadex column chromatographic or a chemical method. The circular dichroism spectra of the resolved complexes were compared with those of the related complexes of the known absolute configuration. The [Cr(bpdo)3]3+ complex in water racemizes spontaneously in dark. The rate is independent of the concentrations of the complex, acid, and the free ligand, and an intramolecular racemization mechanism is suggested.
The Acid-catalyzed Reaction of Alicyclic Ketones with Formaldehyde. III.The Reaction of 3- and 3,5-Methyl-substituted Cyclohexanones with Formaldehyde
Authors: Hirano Fukumi , Wakabayashi Shoji 
Published: July 2006

Abstract
The reaction of 3- and 3,5-methyl-substituted cyclohexanones with formaldehyde in acid media has been studied. The acid-catalyzed reaction gave 2,4,12,14-tetraoxatricyclo[8.4.0.01,6]tetradecane, 2,4-dioxaspiro[5.5]undecan-7-one, and 2,4,8,10-tetraoxatricyclo[4.4.4.01,6]tetradecane derivatives. The effect of the methyl groups on the product distribution has been discussed.
Photoisomerization and Photodimerization of 3-(1- and 2-Naphthyl)acrylate in Bichromophoric Systems
Authors: Tanaka Hideaki , Takamuku Setsuo , Sakurai Hiroshi 
Published: July 2006

Abstract
The photochemical trans-cis isomerization of methyl 3-(1- and 2-naphthyl)acrylate (1Me and 2Me) and the intramolecular (2+2) cycloaddition of ethylene bis[3-(1- and 2-naphthyl)acrylates] (1E and 2E) have been studied in cyclohexane and methanol. The quantum yield of the trans-cis isomerization of 2Me and 2E in methanol was larger than that in cyclohexane, while the yield of the cyclization of 2E showed the reverse. The isomerization is thought to occur via the triplet state, while the cyclization is via the singlet excited state. The triplet yield of 2Me in the polar solvent has been estimated to be larger than in nonpolar solvent. The cyclization of 1E was much slower than that of 2E, and the quantum yield of the reaction of 1Me and 1E did not appreciably depends on the polarity of the solvent.
Nitrogen Compounds in Petroleum. IV. Distribution Profiles of Nitrogen Compounds in Petroleum by Solid-Liquid Chromatography
Authors: Nomura Akira , Morita Yazaemon , Kogure Yukitoshi 
Published: July 2006

Abstract
A simple method for the characterization of nitrogen compounds in petroleum products by the investigation of the distribution profiles of nitrogen compounds using stepwise gradient elution on silica gel has been conducted. Samples were charged onto a 8φ×150 mm glass column containing 3 g of silica gel for column chromatography, followed by 15 ml of hexane to remove the non-polar bulk hydrocarbons from the sample. The eluate collected was removed from the solvent and analyzed for nitrogen, wt % yield and UV absorbance at 220 nm. The same procedure was followed by each 15 ml of 1, 3, 5, 10, 30, 60, 100%(v/v)-THF in hexane eluents. Plots of the nitrogen contents vs. the concentration of eluents gave characteristic patterns for petroleum distillates. The crude and residual oils from different geological sources exhibit similar nitrogen distribution profiles. There are two peak values; the peak at 3%-THF increases and that at 30%-THF decreases as the boiling range of the distillate decreases. Nitrogen compounds are distributed uniformly in a wide range of polar components with regard to adsorptivity on silica gel. The method was further applied to the reaction products of quinoline and indole by irradiation with UV light in isooctane (2,2,4-trimethylpentane) solution.
Electrochemical Synthesis and Reactivity of α-Alkoxy α-Amino Acid Derivatives
Authors: Iwasaki Tameo , Horikawa Hiroshi , Matsumoto Kazuo , Miyoshi Muneji 
Published: July 2006

Abstract
α-Alkoxy α-amino acid derivatives were synthesized in good yields by anodic oxidation of acylaminomalonic acid monoesters in alcohols. Transformation of ethyl N-acetyl-α-methoxyalaninate into ethyl N-acetyl-α,βdehydroalaninate was achieved in an excellent yield by thermal treatment of the former amino acid with a catalytic amount of ammonium bromide. Substitution of the α-alkoxy group of the α-alkoxy amino acids with nucleophiles was effected by tin tetrachloride to afford the α-substituted α-amino acids.
Preparation of S-Vinylsulfilimines
Authors: Yamamoto Tamotsu , Kakimoto Masa-aki , Okawara Makoto 
Published: July 2006

Abstract
For the preparation of S-vinylsulfilimines (1), mainly S-phenyl-N-tosyl-S-vinylsulfilimine, three routes were examined, viz., (A) the reaction of vinyl sulfide with chloramine T, (B) that of 2-haloethyl phenyl sulfide with chloramine T followed by dehydrohalogenation, and (C) that of 2-hydroxyethyl sulfide with chloramine T followed by acetylation of the hydroxyl group and deacetoxylation. Route A has disadvantages of troublesome preparation of vinyl sulfides and low yield. Route B gives the precursor sulfilimine to 1 in good yield only by use of anhydrous chloramine T. Route C gives the best results in view of starting material and yield.
Synthesis and Properties of Bis(cyclopropylphenyl)cyclopropenones and the Tris(p-cyclopropylphenyl)cyclopropenium Ion
Authors: Komatsu Koichi , Tomioka Isao , Okamoto Kunio 
Published: July 2006

Abstract
The reaction of trichlorocyclopropenium tetrachloroaluminate with cyclopropylbenzene has been found to readily afford the disubstitution products, bis(p-cyclopropylphenyl)- (1a), (p-cyclopropylphenyl) (o-cyclopropylphenyl)-, and bis(o-cyclopropylphenyl)cyclopropenones, each of which has been separated and fully characterized spectroscopically. The tris(p-cyclopropylphenyl)cyclopropenium ion (2) could not be obtained by the direct trisubstitution of the trichlorocyclopropenium ion with cyclopropylbenzene, but has been synthesized via two other routes starting from cyclopropenone 1a. The UV and 13C NMR spectral data of the cation 2 indicated the conjugative interaction of the para-cyclopropyl group with the cyclopropenium ring. However, the cation-stabilizing effect of the para-cyclopropyl group, as shown by the pKR+ value (3.23 in 23% ethanol) for 2, is much smaller than in the case of the tris(p-cyclopropylphenyl)methyl cation. This has been interpreted in terms of the decrease in delocalization of the positive charge to the para-position of the cation 2, when compared with the triarylmethyl analogue.
Imidazopteridines. II. Synthesis of Imidazo[1,2-c]pteridines with a Functional Group at the 6-Position
Authors: Sugimoto Takashi , Shibata Keiko , Matsuura Sadao 
Published: July 2006

Abstract
Several imidazo[1,2-c]pteridines with a functional group such as amino, alkylamino, alkoxyl, or hydroxyl group at the 6-position were synthesized by a nucleophilic replacement of 6-methylthioimidazo[1,2-c]pteridine with an appropriate nucleophile. The key intermediate methylthio compound was synthesized by condensation of 4-amino-2-methylthiopteridine with chloroacetaldehyde. Similarly, 4-amino-6,7-dimethyl-2-methylthiopteridine and chloroacetaldehyde gave 2,3-dimethyl-6-methylthioimidazo[1,2-c]pteridine, which was also used as a precursor to synthesize several imidazopteridines analogous to above.
Polyelectrolyte Complexes of [2-(Diethylamino)ethyl]dextran Hydrochloride with Sodium Carboxymethylcellulose
Authors: Kikuchi Yasuo , Koda Takashi 
Published: July 2006

Abstract
Sodium carboxymethylcellulose(anti-thrombogenic material)(CMC) reacted with [2-(diethylamino)ethyl]dextran hydrochloride(anti-cancer material)(EA) having an opposite charge and three groups of different basicity at different hydrogen ion concentrations to form novel water-insoluble precipitates, the so-called polyelectrolyte complex(PEC) comprised of both biomedical materials, focusing on the coagulation of precipitate(PEC) produced. The mole ratio N(EA)/Na(CMC) of the reaction mixture in solution at the start coagulation increased with a lowering of hydrogen ion concentration. This depended on the change of the degree of dissociation of EA and CMC with changing hydrogen ion concentration. The nitrogen contents which describe the mole ratios of EA/CMC in each PEC thus prepared were determined to range from 1.75 to 4.51. It was established that the hydrogen ion concentration and mixing mole ratio of N/Na in solution play an important role in determining the composition ratio of EA/CMC in the PEC. The results of IR, elemental analyses, solubility measurements, degree of swelling in water, color reaction with Toluidine Blue, and blood clotting test for PEC, revealed that the molecular structure of the various PEC’s differed according to the hydrogen ion concentration and the mole ratio of reaction mixture in solution, though all PEC’s were prepared from the same starting materials. It appears that the degree of dissociation and conformation of EA and CMC change with hydrogen ion concentration. The blood clotting tests were performed on a slightly swelled tablet of PEC where it was found that the PEC suppressed coagulation of the blood.
Photoinduced Dechlorination of β-Benzene Hexachloride in Alkaline Alcohols
Authors: Ogata Yoshiro , Takagi Katsuhiko , Sasoh Yasuharu 
Published: July 2006

Abstract
Photo-induced dechlorination of β-benzene hexachloride(β-BHC) in alkaline alcohols has been studied. Benzene is a major product accompanying other minor products such as chlorobenzene, alkoxybenzene, and benzyl alcohols. Their yields vary a great deal depending on the kind of alcohol. The efficiency of reaction and the selectivity of benzene increase in the order : methanol&lt;ethanol&lt;2-propanol. The reaction may go by way of dechlorination of β-BHC with base in the dark giving trichlorobenzenes(predominantly 1,2,4-isomer) followed by its photochemical dechlorination. The radical chain mechanism involving H-abstraction by Cl· atom is presented, since the efficiency is raised ca. 8 times as much as that in the dark.
On the Effects of Crystalline Planes and Purities on Working States of Vanadium Oxide Catalysts in CO-oxidation
Authors: Kera Yoshiya 
Published: July 2006

Abstract
It was confirmed that the kinetics of CO-oxidation over powdered V2O5 under the condition of (PCO⁄PO2) more than 2 differed clearly from that under the (PCO⁄PO2) less than 2 at 450 °C. The activation energies were 5.6 kcal/mol at 250–410 °C and 13 kcal/mol at 410–490 °C under a reductive condition of (PCO⁄PO2)=4.4, and on the other hand 5.9 kcal/mol at 250–490 °C under an oxidative condition of (PCO⁄PO2)=0.43. On a thin crystalline sample, in which the (010) plane was exposed extensively to the surface, a very rapid process appeared at the initial stage but was soon followed by a steady process. The rapid process was explained well by the Elovich law. On the thin crystalline, cautiously purified, the Elovich process did not appear, but the initial rapid process was kept steadily for 10–20 min and then followed by the other steady process. Accompanied by the change in the kinetics during the reaction, the activation energy changed from 2.3 kcal/mol at 271–410 °C and 17 kcal/mol at 410–480 °C to 29 kcal/mol at 271–480 °C under the (PCO⁄PO2)=2.1. Based on these results, the effects of the crystalline planes and the purities on the working states of V2O5 crystal in CO-oxidation are discussed.
Solubility Isotherms of Reciprocal Salt-Pairs of Optically Active Cobalt(III) Complexes
Authors: Fuyuhiro Akira , Yamanari Kazuaki , Shimura Yoichi 
Published: July 2006

Abstract
Two kinds of four-component solubility isotherms consisting of (Λ-[Co(ox)(en)2]+, Δ-[Co(ox)(en)2]+)–(Cl−, X−)–H2O, where X− stands for Δ-[Co(edta)]− or (R,R)-C4H5O6−, have been determined experimentally at 25 °C. It has been found that neither double salt nor solid solution exists and no configurational activity is observed in these systems. The applications of these phase diagrams to the practical optical resolutions are discussed.