bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amination Kinetics of Chloromethylated Polystyrene Accompanied by Acceleration and Deceleration
Authors: Kawabe Hiroshi 
Published: July 2006

Abstract
Procedures to evaluate rigorously the rate constants in the animations of chloromethylated polystyrene which are accompanied by acceleration and deceleration have been developed. The calculated fractional conversions in the reaction of chloromethylated polystyrene with 2-amino-1-butanol in dioxane, accompanied by acceleration, and the reaction with triethylamine in dimethyl sulfoxide, accompanied by deceleration, are proved to be in good agreement with the observed ones. The activation parameters of these reactions, in addition to the kinetic data in N,N-dimethylformamide, support the conclusion that the acceleration and the deceleration are due to the formation of the hydrogen bond and to the electrostatic effect from the neighboring groups in the respective transition states.
Collision Induced Perturbations on the Long-lived Fluorescence of Pyrazine in S1
Authors: Igarashi Hisao , Kaya Koji 
Published: July 2006

Abstract
Collision induced intersystem crossing (slow fluorescence quenching and phosphorescence induction) from selected vibronic levels of pyrazine in S1(nπ*, B3u) was investigated. It was found that slow fluorescence quenching rate at the zero point level exceeds the hard sphere collision rate several times and rapidly approaches it as the excitation energy is increased. On the other hand, phosphorescence induction rate was found to be nearly equal to the collision rate and to have little excitation energy dependence. These differences were discussed on the basis of the collision induced relaxation mechanisms.
Encapsulation of Krypton with (K, MII)-A Zeolites
Authors: Itabashi Keiji , Takaishi Tetsuo , Ohgushi Tatsuo 
Published: July 2006

Abstract
The encapsulation of krypton is realized with zeolite A, having compositions (K12−2xMxII-A with 1.11≤x≤3.78, at temperatures lower than 300 °C and a pressure of 3.7×106 Pa. This encapsulation condition is much milder than the usual one, 350 °C and 4.2×108 Pa, which is adopted in industry. Such lowerings of the encapsulation temperature and pressure are caused by bivalent cations introduced through ion-exchanges. The result is an experimental evidence to the existence of the ion-loosening effect proposed in preceding papers.
Determination of Thermodynamic Properties of Gibbsite from Its Solubility Data in NaOH Solutions
Authors: Chang Byong-Tae 
Published: July 2006

Abstract
A reasonable method for determination of thermodynamic properties of alumina hydrates from their solubility data in alkaline pH range was presented and applied to the solubility data of gibbsite in NaOH solutions with success. When log(Ks⁄aw), where Ks=mHmAl and aw is the activity of water, was plotted against a Debye-Hiickel function of the ionic strength I, I1⁄2⁄(1+BtalI1⁄2), a linear relationship to moderately high ionic strengths was found over the range of temperatures from 40 to 110 °C, having the theoretical Debye-Hiickel limiting slope and the intercept of logKs° at I=0. Assuming the same ionic size parameters, a1=a2, the solubility product (Ks°) of gibbsite was found to depend upon temperature up to 110 °C as follows: logKs°=−4064⁄T−1.54 or −4023⁄T−1.65. At high ionic strengths above 1.0, log(Ks⁄aw) showed positive deviations from the straight line, which may be attributed to the formation of complex ions, e.g., Al2O(OH)62−, or the dehydration of Al(OH)4− to AlO(OH)2− and AlO2− ions.
Negative Ions Formed by Vacuum Spark Discharge. III. Polyatomic Negative Ions of the Elements in A-Subgroups on the Periodic Table
Authors: Kishi Hiroshi 
Published: July 2006

Abstract
Polyatomic negative ions for almost all of the elements in A-subgroups on the periodic table were tested by the spark discharge type ion source mass spectroscopy. A large number of polyatomic negative ions such as “polymer” negative ions, hydride negative ions, oxide negative ions, and carbide negative ions, could be detected. The results are discussed with reference to the reported values of electron affinities of the molecules and to the reported results by other methods of formation.
Negative Ions Formed by Vacuum Spark Discharge. IV . Polyatomic Negative Ions of the Elements in B-Subgroups on the Periodic Table
Authors: Kishi Hiroshi 
Published: July 2006

Abstract
Polyatomic negative ions for almost all of the elements in B-subgroups on the periodic table were tested by the spark discharge type ion source mass spectroscopy. Polyatomic negative ions such as hydride negative ions, oxide negative ions, and carbide negative ions could be detected. The results are discussed with reference to the reported results by other methods of formation.
Digitally Controlled Automatic Coulometric Karl Fischer Titrator
Authors: Umemoto Kisaburo 
Published: July 2006

Abstract
An automatic coulometric Karl Fischer titrator capable of direct readout of the water titrated and the background of titration was constructed. Control of the generation of reagent was carried out by a digital counting method. The over- and under-titration was minimized by holding the level of reagent at the start and the end of titration as close as possible. Details of the circuit configuration were presented. The precision of determination was ca. ±2 μg and ±1–±2 μg for the automatic titration of 1 mg and 10–500 μg of water, respectively. Water of less than 20 μg was titrated within a precision of 1 μg by watching the drift and subsequent recovery of the blank level.
Prerequisites for the Enhancement of Formose Formation in the Presence of Hydroxy Oxo Compounds
Authors: Sakai Tomoya , Ishizaki Masahiko , Kobayashi Katsuaki , Goto Masafumi 
Published: July 2006

Abstract
The enhancement of formose formation in the presence of several hydroxy oxo compounds was examined in an aqueous Ca(OH)2 solution. Four terminal hydroxy oxo compounds, 2-hydroxyacetophenone, 1,3-dihydroxyacetone, Dl-glyceraldehyde, and d-glucose, were confirmed to accelerate the reaction, but two internal hydroxy oxo compounds, 2-hydroxypropiophenone and acetoin, were found not to be effective. The acceleration efficiency was larger for a system in which hydroxy oxo compounds were introduced to an aqueous mixture of Ca(OH)2 and formaldehyde than for a system in which formaldehyde was introduced to an aqueous mixture of Ca(OH)2 and the hydroxy oxo compounds. The difference in the acceleration efficiencies between the two procedures of reagent introduction was large for 2-hydroxyacetophenone and 1,3-dihydroxyacetone. This is accounted for by the rapid conversions of the added hydroxy oxo compounds in an aqueous Ca(OH)2 solution.
Structure and Synthesis of (+)-Shonanol
Authors: Matsumoto Takashi , Imai Sachihiko , Kawashima Hiroyuki , Mitsuki Masanori 
Published: July 2006

Abstract
The structure of shonanol was restudied and found to be 12-hydroxyabieta-2,8,11,13-tetraen-1-one (1) by the following synthesis. A Grignard reaction of methyl (+)-12-methoxyabieta-8,11,13-trien-18-oate with phenylmagnesium bromide, followed by treatment with lead tetraacetate and calcium carbonate afforded a mixture of Δ3−, Δ4−, and Δ4(18)-19-nor compounds. This was oxidized with selenium dioxide to give (+)-12-methoxy19-norabieta-4(18),8,11,13-tetraen-3α-ol. This alcohol was converted to (+)-12-methoxyabieta-5,8,11,13-tetraen-3-one (6) by the known procedure. Reduction of 6 with lithium aluminium hydride, followed by catalytic hydrogenation, yielded (+)-12-methoxyabieta-8,11,13-trien-3β-ol (8) and a small amount of its cis isomer. The compound (8) was then converted to (+)-12-methoxyabieta-1,8,11,13-tetraen-3-one (12) by a series of reactions: oxidation with pyridinium chlorochromate, bromination with pyridinium tribromide, and dehydrobromination with lithium carbonate and lithium bromide. Demethylation of 12 with boron tribromide gave (+)-12-hydroxyabieta-1,8,11,13-tetraen-3-one. Oxidation of 12 with alkaline hydrogen peroxide, followed by treatment with hydrazine hydrate, gave (+)-12-methoxyabieta-2,8,11,13-tetraen-1α-ol; this was oxidized with Jones reagent to give the corresponding 1-oxo compound. The 1-oxo compound was finally demethylated with boron tribromide to yield (+)-1, whose spectra were identical with those of natural shonanol.
Enzymatic Synthesis of New Pyridine Nucleosides. Clitidine and Its Amide Derivative
Authors: Tono-oka Shuichi , Sasahara Yasuhiko , Sasaki Akio , Shirahama Haruhisa , Matsumoto Takeshi , Kakimoto Shichiro 
Published: July 2006

Abstract
Two β-NAD-analogs were prepared utilizing a base-exchange reaction catalyzed by pig-brain NADase. These analogs were proved to contain a methyl 1,4-dihydro-4-iminonicotinate and a 1,4-dihydro-4-iminonicotinamide moiety. By successive hydrolytic degradations of these analogs, 1,4-dihydro-4-iminopyridine β-ribosides with 3-carboxyl and 3-carbamoyl groups were prepared in good yields. The former compound was identical with clitidine, a toxic pyridine nucleoside recently isolated from a toadstool. The present synthesis confirmed the 1,4-dihydro-4-imino β-riboside structure of clitidine. Preliminary biological tests showed that the 3-carbamoyl compound was more toxic than clitidine, suggesting that the amide derivative of clitidine is an essential toxic substance in the toadstool.
The Pormylation of an Aromatic Nucleus by the Use of 2-Ethoxy-1,3-dithiolane
Authors: Jo Shigeo , Tanimoto Shigeo , Sugimoto Toyonari , Okano Masaya 
Published: July 2006

Abstract
The reaction of various phenols with 2-ethoxy-1,3-dithiolane proceeded smoothly in the presence of BF3·Et2O to afford 1,3-dithiolan-2-ylated phenols, which were readily hydrolyzed to the corresponding aldehydes. This process was also extended to N,N-dimethylaniline and indole.
The Acid-catalyzed Decomposition of α-Diazo β-Hydroxy Ketones
Authors: Miyauchi Kazuo , Hori Kimiaki , Hirai Tsuguji , Takebayashi Matsuji , Ibata Toshikazu 
Published: July 2006

Abstract
The proton acid-catalyzed decomposition of 3-aryl-2-diazo-3-hydroxy-1-phenylpropanone (1) gave aryl and hydrogen migration products. The former was the enol-form (2) of 2-aryl-3-phenyl-1,3-propanedione and the latter was the enol- (3) and keto-form (4) of 1-aryl-3-phenyl-1,3-propanedione. The product ratios, 2/(3+4), were affected by the catalysts and solvents used. More polar solvents favored the formation of aryl migration products (2). On the other hand, the BF3-catalyzed decomposition of 1 gave acetylenic ketones as main products along with 2, 3, and 4. The TsOH-catalyzed decomposition of 2-diazo-3-hydroxy-3-phenyl-1-indanone, (cyclic α-diazo β-hydroxy ketone), gave 2-phenyl-1,3-indandione quantitatively through phenyl migration.
Transfer Free Energies of Fluoride Ion in Aqueous Mixtures of Some Organic Solvents
Authors: Bhattacharya Abhijit , Das Kaushik , Das Asim Kumar , Kundu Kiron Kumar 
Published: July 2006

Abstract
Standard free energies of transfer, ΔGt°, of potassium fluoride (KF) from water to aqueous mixtures of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetonitrile (ACN), 1,2-dimethoxyethane (DME), and 2-methoxyethanol (ME) have been determined at 25 °C from emf measurements performed on the double cell: Pb(Hg)–PbF2/KF(m), solvent/K(Hg)/KF(m), water/PbF2–Pb(Hg). ΔGt° values of F− were obtained from these values using the corresponding values of K+, as obtained earlier by use of tetraphenylarsonium tetraphenylborate reference electrolyte assumption. In each solvent system ΔGt°(F−) values are found to be increasingly positive with cosolvent composition reflecting the pronounced destabilization of F− and their relative order : DME&gt;DMSO≥DMF&gt;&gt;ACN≈ME conforms to what is expected from the relative ‘aproticity’ of the dipolar aprotic cosolvents and that induced in the protic ME by the possible intramolecular H-bonding. The observed larger destabilization of F− compared to OH− in ME–water system has been attributed to the H-bonding effect of the protic cosolvent ME and the reverse behaviour in DME–water and DMSO–water systems to the absence of such effect of these cosolvents. Moreover, tests of Feakins-type extrapolation for assigning individual ion contribution using ΔGt°(KF) values along with those of other potassium halides, provided some important reflections on the inadequacy of such plots made without the data points of F−.
14N Nuclear Quadrupole Resonance Spectra of K2SrCu(NO2)6, K2BaCu(NO2)6, and Cs2PbCu(NO2)6
Authors: Asaji Tetsuo , Ishikawa Jun , Ikeda Ryuichi , Nakamura Daiyu 
Published: July 2006

Abstract
The 14N NQR frequencies of K2SrCu(NO2)6, K2BaCu(NO2)6, and Cs2PbCu(NO2)6 were determined at various temperatures below about 155, 67, and 235 K, respectively. The results are discussed in referring to their crystal structure.
Kinetics of the Decarboxylation of Benzylmalonic Acid, Ethylmalonic Acid, and Dimethylmalonic Acid in Hydroxylic Solvents
Authors: Biswas Mihir K , Majumdar Dilip K 
Published: July 2006

Abstract
Kinetics of the decarboxylation of benzylmalonic acid, ethylmalonic acid, and dimethylmalonic acid have been shown to follow first order rate equation in several solvents, namely alkanediols and diethylene glycol (DEG), polyethylene glycol (PEG), and polypropylene glycol (PPG). The enthalpy and entropy of activation for the decarboxylation reactions were determined and the plot of ΔH\eweq vs. ΔS\eweq was found to be linear through all the solvents.
A Novel Preparation of Bicyclo[3.2.2]nonanes and Bicyclo[4.2.2]decanes Substituted at the Bridgeheads
Authors: Sakai Yasuo , Terashima Kaoru , Tobe Yoshito , Odaira Yoshinobu 
Published: July 2006

Abstract
A novel preparation of 1,5-disubstituted bicyclo[3.2.2]nonanes and 1,6-disubstituted bicyclo[4.2.2]decanes based on the one-pot reaction of [3.2.2]- and [4.2.2]propellanecarboxylic acids with 2 equiv. of lead tetraacetate, followed by catalytic hydrogenation, is described.
Studies on the Complex Formation between o-Quinones and Metal Chlorides in Nitromethane Solution
Authors: Kataoka Kazuaki , Kimura Sumihisa , Shirakawa Fumiko , Sasaki Yoshio 
Published: July 2006

Abstract
Complex formation between several kinds of metal chlorides and 4,5-dimethoxy-1,2-benzoquinone (1) or 4-methoxy-1,2-naphthoquinone (2) has been studied by means of NMR and spectrophotometry in CH3NO2. Stability constants of the 1 : 1 complex were found to decrease in the order of SnCl4&gt;InCl3&gt;ZnCl2&gt;BiCl3&gt;SbCl3&gt;HgCl2. ΔδML and Δνmax, which indicate the change in the chemical shift and the wavenumber on the formation of the 1 : 1 complex, were also arranged in the above order. The same order was reproduced from an electrostatic potential. Both ΔδML and Δνmax were proved to be a convenient scale for the relative acceptor strength of metal chlorides. For the basicity of o-quinones, the order of 1&gt;2 was obtained from the thermodynamic data and from the negative charge on the carbonyl oxygens. The solute-solvent interaction model was also found appliciable in this system.
Interaction between Pyrazine and Halomethanes. I. Complex Formation between Pyrazine and Halomethanes at Room Temperature
Authors: Kuroi Tatsuaki , Gondo Yasuhiko , Kuwabara Masamichi , Shimada Ryoichi , Kanda Yoshiya 
Published: July 2006

Abstract
The absorption spectrum of pyrazine has been studied at room temperature in various mixed solvents of cyclohexane and halomethanes such as carbon tetrachloride, chloroform and dichloromethane. With increasing concentration of halomethane, the singlet-singlet (S-S) and singlet-triplet (S-T) n→π* absorptions decrease in intensity and become structureless, whereas the S-S π→π* absorption remains essentially unchanged. The observations are attributed to the complex formation between pyrazine and halomethanes involving the non-bonding electrons in pyrazine. From the concentration and temperature dependences of the n→π* absorption spectra, the equilibrium constants, enthalpy and entropy changes have been obtained for the complex formation in all the systems studied. The equilibrium constants obtained from the S-S and S-T n→π* absorptions are in good agreement with each other.
Interaction between Pyrazine and Halomethanes. II. Effects of Halomethanes on the Phosphorescence of Pyrazine at 77 K
Authors: Kuroi Tatsuaki , Gondo Yasuhiko , Kuwabara Masamichi , Shimada Ryoichi , Kanda Yoshiya 
Published: July 2006

Abstract
The phosphorescence and phosphorescence excitation spectra of pyrazine have been studied at 77 K in various mixed solvents of cyclohexane and halomethanes such as carbon tetrachloride, chloroform, and dichloromethane. When the halomethane concentration was low (below 10−2 mol dm−3), only the cyclohexane-phase phosphorescence was observed at 77 K; the lower energy components of the well-known doublet band series in the cyclohexanephase phosphorescence were found to decrease in intensity relative to the higher energy components, with increasing concentration of halomethane. When the halomethane concentration was raised to a range higher than 10−1 mol dm−3, where the complex formation between pyrazine and the halomethanes was confirmed through absorption spectroscopy, new phosphorescence bands appeared in the 373–375 nm region for all the systems studied. With further increase of the halomethane concentration, the new bands decreased in intensity or disappeared, and the phosphorescence approached to those in the pure halomethanes. Comparison of the absorption and phosphorescence excitation spectra shows that the new phosphorescence bands result from the 1 : 1 pyrazine–halomethane complexes. The possibility of hydrogen-bonding species formation with chloroform and dichloromethane has been discussed in the light of the phosphorescence spectra studied in the ethanol–cyclohexane mixed solvents.
The trans-cis Isomerization of Potassium Diaquabis(oxalato)chromate(III) in Various Organic Solvent–Water Mixtures
Authors: Uchida Kengo , Takinami Yoshinobu 
Published: July 2006

Abstract
Kinetics of the trans-cis isomerization of K[Cr(ox)2(H2O)2] have been investigated in binary mixed solvents, including ethanol–, dioxane–, and acetone–water mixtures. The first-order rate constant decreases with an increase in the concentration of an organic solvent. A similar decrease by the addition of an organic solvent was observed in the presence of univalent and bivalent cations. These results are in contrast to those for the analogous malonato complex, and suggest that both dissociation and twist mechanisms are involved in the reaction.
Solubility Isotherms of Systems Containing Optically Active Tris(ethylenediamine)cobalt(III) Ion. II. Reciprocal Salt-pairs, (Λ-[Co(en)3]3+, Δ-[Co(en)3]3+)–(I−, (R,R)-C4H4O62−), at 25 °C
Authors: Fuyuhiro Akira , Yamanari Kazuaki , Shimura Yoichi 
Published: July 2006

Abstract
A four-component solubility isotherm consisting of Λ-[Co(en)3]3+, Δ-[Co(en)3]3+)–(I−, (R,R)-C4H4O62−)–H2O was determined at 25 °C. It was found that four double salts rac-[Co(en)3]I3·H2O, Λ-[Co(en)3]I(d-C4H4O6)·2H2O, Λ-[Co(en)3]0.48·Δ-[Co(en)3]0.52(d-C4H4O6)1.5·5H2O, and Δ-[Co(en)3]I(d-C4H4O6)·nH2O exist, six invariant points appearing. Application of this phase diagram to practical optical resolution is discussed in comparison with a system containing Br−. Some models of phase diagram for effective optical resolution in reciprocal salt-pairs are proposed.
The Initial Sintering of Alkaline Earth Oxides in Water Vapor and Hydrogen Gas
Authors: Ito Tomoyasu , Fujita Masato , Watanabe Masahiro , Tokuda Taneki 
Published: July 2006

Abstract
The initial sintering (crystallite growth and surface-area diminution) of freely dispersed powders was studied. For MgO in H2O vapor, the sintering rate at 1073 K was directly proportional to the water-vapor pressure, PH2O, in the range of 27–2700 Pa, and the apparent activation energy, E, for the sintering was 137 kJ mol−1. These facts lead to the conclusion that, in this system, the surface migration of O2− caused by the repetition of the adsorp-tion-desorption cycle of the H2O molecule is rate-determining step for the sintering. For CaO in H2O vapor, the rate-determining step appears to be migration on and/or near the surface of a cation vacancy produced by the H2O adsorption, judging upon the facts that the sintering rate at 873 K was proportional to PH2O0.34 in the range of 11–1600 Pa and that E was 79.4 kJ mol−1. For MgO in H2 gas, the sintering rate at 1123 K was approximately proportional to the hydrogen pressure in the range of 3.3–66.5 kPa and E was 310 kJ mol−1, indicating that the sintering in H2 was caused by H2O vapor formed upon the desorption of the surface hydroxyl groups which had been produced by a heterolytic dissociative adsorption of H2.
Molecular Conformations of 4-Aminomethyl-1-cyclohexanecarboxylic Acids in Aqueous Solution
Authors: Yanaka Mikirô , Enomoto Satoru , Inoue Yoshio , Chûjô Riichirô 
Published: July 2006

Abstract
The structures of cis- and trans-4-aminomethyl-1 -cyclohexanecarboxylic acids were studied by proton and carbon-13 NMR, and by semiempirical molecular orbital methods (CNDO/2 and MNDO). Both isomers exist in zwitter ionic forms in aqueous solution. It was found that the most stable conformations for them are all staggered forms: the diequatorial conformer in the trans form and the axial carboxyl group in the cis form. These preferred conformers are similar to those in crystalline states. In these conformers the deformation is very small in the cyclohexane ring of the trans form. The atomic distance between the nitrogen of amino group and the carbon of carboxyl group in the preferred conformer of trans form is 0.65 nm and that in cis form is 0.55 nm. This distance of 0.65 nm will play an important role in the antifibrinolytic effect.
Liquid Crystal Formation in Binary Systems. III. Effect of the Central Double Bond Linkage on the Induction of Nematic Liquid Crystals
Authors: Araya Kotaro , Matsunaga Yoshio 
Published: July 2006

Abstract
The effect of central double bond linkage on the induction of liquid crystals has been examined employing eight binary mixtures of potentially mesomorphic electron donors and acceptors of the type 4-X–C6H4–Z–C6H4–OC2H5-4. The central linkage Z is –N=N–, –CH=N–, or –CH=CH– group. The terminal substituent X is a dimethylamino group in the donor compounds and a nitro group in the acceptor compounds. A stable nematic liquid crystal is observable with the systems of azo-azo and azo-azomethine compounds. When the acceptor is the nitro derivative of stilbene, a 2 : 3 molecular complex is formed and no liquid crystal can be found, irrespective of whether the partner is an azo or azomethine compound. The latent induction of nematic liquid crystals in these combinations has been proved by studies on the phase diagrams of the pseudo-binary systems with a reference nematogen, azoxy-dianisole. The nematic liquid crystal-isotropic liquid transition temperatures of both the component compounds and the equimolar mixtures depend on the central double bond linkage: the order is –CH=CH–&gt;–N=N–&gt;–CH=N–. On the other hand, the order of –N=N– and –CH=N– groups is reversed in the extent of the induction of nematic liquid crystals.
UV Absorption Studies of the Pyrolysis of Butane in Shock Waves
Authors: Koike Tohru , Morinaga Kihei 
Published: July 2006

Abstract
The UV absorption measurements at 216 nm were carried out for three shock-heated mixtures, 1, 2, and 2 8% n-C4H10 diluted in Ar, in the temperature range of 1290–1610 K and at about half atmospheric pressures. From the initial absorption rise, which can be attributed to the CH3 growth, the rate constant of the reaction, n-C4H10=CH3+n-C3H7, was evaluated as k2=8.9×1013exp (−71.9 kcal⁄RT) (s−1). A computer modeling using a 44-reaction mechanism including the k2 value so evaluated could reproduce the absorption early in the reaction and in the temperature range of 1420–1610 K with a reasonable value.