bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineralogical Characterization of the Reference Material of “Pond Sediment”
Authors: Iwata Yasuo , Haraguchi Hiroki , Van Loon Jon C , Fuwa Keiichiro
Published: July 2006

The identification of rock-forming and clay minerals contained in the reference material of “Pond Sediment” (Reference Material NIES No. 2 from the National Institute for Environmental Studies, Japan) has been made with X-ray diffraction method. It was found that the sediment contained α-quartz and feldspars as the principal components along with small quantity of pyroxenes, amphiboles, and some clay minerals. The sediment sample was treated chemically for extraction, and also separated with density and with grain sizes. Elemental compositions of such extracted or separated fractions of the sediment were determined by inductively coupled argon plasma emission and atomic absorption spectrometry. The identified minerals and the elemental distributions in the separated fractions helped to characterize the pond sediment.
Mössbauer and ESR Studies of Potassium Borophosphate Glasses
Authors: Nishida Tetsuaki , Miyamoto Yoshiaki , Takashima Yoshimasa
Published: July 2006

A linear decrease in isomer shifts of Fe3+ and Fe2+ was observed with an increase in alkali content of borophosphate glasses. The decrease is attributed to a change in the role of iron from a network modifier to a network former, or a decrease in the interatomic distance between iron and oxygen atoms. A linear decrease in quadrupole splitting and linewidth was also observed with increasing alkali content, and the decrease is attributed to the increased symmetry around iron nucleus. A linear decrease in relative absorption area of Fe2+ in Mössbauer spectra was also observed with increasing alkali content of the glasses. This result is attributed to an increased oxidation atmosphere brought about by alkali oxide into BPO4 units. Gamma-ray irradiation (1×108 R) experiments resulted in no change in these Mössbauer parameters, indicating that the glasses are less sensitive to γ-rays than borate or phosphate glasses. ESR absorption intensity of PO42− observed in γ-ray irradiated, iron-free borophosphate glasses increased linearly with an increase in the alkali content in the lower alkali region, and the increase is attributed to a linear increase in the fraction of non-bridging oxygen in PO4 tetrahedra constituting BPO4 (and PO4) units.
CIDEP Study of Durosemiquinone Radical in Various Solvents
Authors: Kanemoto Akihiko , Niizuma Sigeya , Konishi Siro , Kokubun Hiroshi
Published: July 2006

F-pair polarization and triplet mechanism (TM) polarization of durosemiquinone radical produced by light irradiation of duroquinone-phenol systems were discriminated at 260 K in a simple way based on the analysis of the enhancement factors in the steady-state method with intermittent light irradiation. Both polarizations are not so sensitive to viscosity or polarity of solvents. TM enhancement factor is nearly constant (−0.8) in wide range of viscosity (2.5–25 cP, 1 cP=0.001 Pa s). F-pair polarization is suppressed in some extent by halogenated solvents while TM polarization is not affected by such solvents.
Photooxidation of Some Aromatic Sulfonic Acids with Alkaline Hypochlorite
Authors: Kimura Makoto , Ogata Yoshiro
Published: July 2006

Photochemical oxidation of aromatic sulfonic acids such as p-cumenesulfonic, 2-mesitylenesulfonic, 1- and 2-naphthalenesulfonic acids with aqueous sodium hypochlorite has been studied. Addition of a large excess of alkali enhances the decomposition of sulfonic acids remarkably. p-Cumenesulfonic and 2-mesitylenesulfonic acids are oxidized faster than 1- and 2-naphthalenesulfonic acids. The photooxidation of sulfonic acids with an equimolar amount of hypochlorite gives intermediary oxidation products involving desulfonation to parent hydrocarbons, aromatic hydroxylation, side-chain oxidation, and ring cleavage; e.g., p-cumenesulfonic acid gives cumene, 2- and 4-isopropylphenol and 2-phenyl-2-propanol; 1- and 2-naphthalenesulfonic acids give phthalic anhydride. Light-absorbing aromatic sulfonic acids sensitize the decomposition of hypochlorite ion leading to hydroxyl radical, which reacts mainly with ground state sulfonic acid to give radical intermediates. The photooxidation may also involve direct C–S bond fission of sulfonic acids.
Studies on the Polymerization of Acrolein Oxime. XVII. The Structure of the β-Form of the Bicyclic Trimer from Methacrylaldehyde Oxime
Authors: Ota Tadatoshi , Masuda Seizo , Tanaka Hitoshi , Inazawa Yasuo , Kido Masaru
Published: July 2006

The thermal oligomerization of methacrylaldehyde oxime leads to 2,4,7-trimethylperhydroisoxazolo[2,3-a]pyridine-2,7-dicarbaldehyde dioxime (1). The β-form of 1 was separated, and its crystal structure was determined by X-ray analysis. It is monoclinic with space group P21/c, a=13.274(11), b=8.652(7), c=11.618(14) Å, β=96.73(8)°, and Z=4. The molecules are linked by two N···O hydrogen bonds, with the N(13)···O(14) and N(8)···O(18) distance of 2.824(5) and 2.897(5) Å respectively.
Furanosesquiterpenoids: Total Synthesis of Pallescensins 2, F, and G
Authors: Matsumoto Takashi , Usui Shuji
Published: July 2006

Oxidation of the synthetic pallescensin 1 with m-chloroperbenzoic acid, followed by treatment of the resulting epoxide with lithium diethylamide, afforded 3-[2-(2-furyl)ethyl]-4,4-dimethyl-2-methylenecyclohexanol (6). The alcohol 6 was dehydrated with refluxing hexamethylphosphoric triamide to give pallescensin 2. Oxidation of 6 with pyridinium chlorochromate, followed by intramolecular cyclization with 85% phosphoric acid, afforded 5,5a,6,7,8,9,9a,10-octahydro-6,6-dimethyl-4H-benzo[5,6]cyclohepta[1,2-b]furan-9-one. This was converted into the corresponding α,β-unsaturated ketone (10) via an α-phenylseleno ketone. Reduction of 10 with lithium aluminium hydride, followed by dehydration with hexamethylphosphoric triamide at 200–210 °C, afforded pallescensin G, which was further isomerized to pallescensin F.
Synthetic Studies on the Validamycins. I. Synthesis of β-d-Glucopyranosylvalidamine: 1l-2-O-(β-d-Glucopyranosyl)-(1,3,4/2,6)-4-amino-6-hydroxymethyl-1,2,3-cyclohexanetriol
Authors: Ogawa Seiichiro , Shibata Yasuhito , Chida Noritaka , Suami Tetsuo
Published: July 2006

β-d-Glucopyranosylvalidamine, the structure of which had first been assigned to a degradation product of validamycin A, was synthesized by condensation of a protected validamine with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide, followed by removal of protecting groups. The synthesized β-d-glucopyranoside was not identical with an authentic sample derived from the antibiotic.
Synthetic Studies on the Validamycins. II. Synthesis of 1l-1-O-(β-d-Glucopyranosyl)-(1,3,4/2,6)-4-amino-6-hydroxymethyl-1,2,3-cyclohexanetriol
Authors: Ogawa Seiichiro , Chida Noritaka , Ito Hiroyuki , Suami Tetsuo
Published: July 2006

The title β-d-glucopyranoside was synthesized via an unequivocal route and found to be identical with β-d-glucopyranosylvalidamine derived from antibiotic validamycin A. The position at which the validamine moiety is substituted with d-glucopyranose in validamycin A is revised to C-1 on the basis of the present synthesis.
Synthetic Studies on the Validamycins. III. Bromination of Dl-Tri-O-acetyl-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol. Preparation of Several Branched-chain Unsaturated Cyclitols Related to Valienamine
Authors: Toyokuni Tatsushi , Abe Yasuo , Ogawa Seiichiro , Suami Tetsuo
Published: July 2006

Bromination of Dl-tri-O-acetyl-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol with bromine in an appropriate solvent yielded mainly two 1,4-addition products, from which several branched-chain unsaturated cyclitols, related to biologically interesting valienamine, were selectively prepared. Reaction courses are discussed for the bromination of the diene and the debromination of the bromo(bromomethyl)cyclohexenetriol triacetates obtained under various conditions.
Effects of Divalent Metal Cations on Circular Dichroism and 1H Nuclear Magnetic Resonance Spectra of Linear and Cyclic Peptides Having Side-chain Imidazolyl and Acetamido Groups
Authors: Kodaka Masato , Shimizu Toru , Hatano Masahiro
Published: July 2006

A linear peptide, N-t-butoxycarbonyl-S-acetamidomethyl-l-cysteinyl-d-leucyl-l-histidyl-S-acetamidomethyl-l-cysteinyl-d-leucyl-l-histidine methyl ester (1) was synthesized by the solid phase method. Subsequent cyclization by the azide method offered a cyclic peptide, cyclo-S-acetamidomethyl-l-cysteinyl-d-leucyl-l-histidyl-S-acetamidomethyl-l-cysteinyl-d-leucyl-l-histidyl (2). The circular dichroism (CD) and 1H NMR were observed for these peptides 1 and 2, in the absence and presence of metal cations, Zn(II), Ca(II), Mg(II). Spectral results for Zn(II) complexes indicated striking contrasts to those of Ca(II) and Mg(II) complexes. Thus, in H2O, the addition of Zn(II) caused CD spectral changes for both peptides, while Ca(II) and Mg(II) did not cause changes in any CD spectral region. In methanol, the additions of Zn(II) and Ca(II) caused CD changes, while the addition of Mg(II) did not cause any CD changes. The changes caused by adding Zn(II) were quite different from those by Ca(II), suggesting that Zn(II) is coordinated with the peptides in a mode different from that of Ca(II). 1H NMR data also suggested the different coordination mode between these two metal complexes in methanol.
Lewis Acid Mediated Synthesis of 2-Alkenenitriles Using C,N-Bis(trimethylsilyl)ketenimine and Carbonyl Compounds
Authors: Matsuda Isamu , Okada Hisashi , Izumi Yusuke
Published: July 2006

2-Substituted 2-alkenenitriles are obtained in the condensation reaction of carbonyl compounds with C,N-bis(trimethylsilyl)ketenimine in the presence of Lewis acid. The combination of tris(trimethylsilyl)ketenimine and aldehydes results in the high E-selective formation of 2-trimethylsilyl-2-alkenenitriles. Among some Lewis acids, magnesium bromide gives the best E-selectivity in the formation of 2-trimethylsilyl-2-undecenenitrile. Stereospecific protodesilylation of 2-trimethylsilyl-2-alkenenitriles in an aqueous methanol solution of potassium fluoride accomplishes a new route to (Z)-2-alkenenitriles from aldehydes.
Photochemical Nitrogen Extrusion of 5-Amino-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles. Formation of Unusual Pyrroles
Authors: Ito Masato M , Nomura Yujiro , Takeuchi Yoshito , Tomoda Shuji
Published: July 2006

Photolysis of 4-alkyl-5-ammo-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles gave not 3-alkylpyrroles, but unexpected 2-alkylpyrroles in 80–83% yields. 1-Vinylaziridines were assumed as a possible intermediate of this unusual pyrrole formation. In the photolysis of 7a-morpholino-1-styryl-3a,4,5,6,7,7a-hexahydro-1H-1,2,3-benzotriazole, however, nitrogen extrusion did not occur, but trans-cis isomerization took place.
Hydrolysis of Some Chromogenic Substrates and Adenosine Triphoshate Catalyzed by Phosphodiesterase-phosphomonoesterase from Fusarium moniliforme
Authors: Yoshida Hiroshi , Kawai Masayuki , Okimura Chiseko , Hirama Nobuyuki , Konno Osamu
Published: July 2006

For comparison with known phosphodiesterases, the mode of action of phosphodiesterase-phosphomonoesterase from Fusarium moniliforme toward some key substrates was examined. The enzyme catalyzed the hydrolysis of either thymidine 3′-(4-nitrophenylphosphate) or thymidine 5′-(4-nitrophenylphosphate). The former substrate was hydrolyzed processively into thymidine, inorganic phosphate and 4-nitrophenol, whereas the latter was split into 4-nitrophenol and thymidine 5′-phosphate. The kinetic constants determined on the basis of 4-nitrophenol liberation were: Km=4.6 mmol dm−3 and kcat=115 s−1 for thymidine 3′-(4-nitrophenylphosphate); Km=0.46 mmol dm−3 and kcat=19.7 s−1 for thymidine 5′-(4-nitrophenylphosphate) at pH 5.3 and 37 °C. 4-Nitrophenyl phenylphosphonate was a good substrate for the enzyme showing kinetic constants Km=1.4 mmol dm−3 and kcat=360 s−1 at pH 5.3 and 37 °C. However, its chiral thio analogue, O-(4-nitrophenyl) phenylphosphonothioate, was hydrolyzed by the enzyme only very slowly in a stereo-nonspecific manner. The three phosphoryl groups in adenosine triphosphate was removed by the enzyme sequentially from the terminal position. These findings have made the uniqueness of Fusarium phosphodiesterase-phosphomonoesterase clearer.
Film Dichroism. VI. Linearly-polarized Absorption Spectra of Neutral and Divalent 3,6-Diaminoacridine Dyes in the Stretched Poly(vinyl alcohol) Film
Authors: Yamaoka Kiwamu , Shimadzu Mitsuaki
Published: July 2006

The linear dichroic spectra of the neutral (uncharged) and divalent (doubly charged) Acridine Orange, Acridine Yellow, and Proflavine were measured at 25 °C in the visible and UV wavelength regions by the film dichroism method. These 3,6-disubstituted symmetric acridine dyes were molecularly dispersed in the heattreated poly(vinyl alcohol) film by the staining method. The neutral and divalent dye species were prepared by adding a sufficient amount of sodium hydroxide or sulfuric acid to the staining dye solutions. The wavelength dependence of the reduced dichroism, ΔA/A, of the neutral species at a given stretch ratio was very similar to that of the monovalent species previously reported [Bull. Chem. Soc. Jpn., 52, 3163 (1979)]. Values of ΔA/A for the divalent species were nearly constant over the entire wavelength region 550–220 nm. The long-axis and short-axis polarized component (Az and Ay) spectra were computed for the neutral dye species from the observed parallel- and perpendicular-polarized dichroic spectra by using a reduction procedure. The broad, principal band of each dye species in the visible region was deduced to be a composite of two orthogonal (a strong Az and a weak Ay) electronic transitions.
Crystal Structure and Related Properties of Phenothiazine Cation Radical-Hexachloroantimonate. Monoclinic(I) Form
Authors: Uchida Tokiko , Ito Masanori , Kozawa Kozo
Published: July 2006

Three forms of crystals were obtained from mixed solutions of phenothiazine and SbCl5; the crystal structure of the monoclinic(I) modification was determined using 2827 reflections at room temperature. Crystal data: (C12H9NS)+·SbCl6−, F.W.=533.7, monoclinic, a=16.253(3), b=14.334(1), c=15.786(3) Å, β=104.07(1)°, space group C2/c, Dm=2.00, Dx=1.99 g cm−3, Z=8, μ=25.73 cm−1 (Mo Kα). The structure was solved by the heavyatom method and refined by block-diagonal least-squares method to R=0.072. The crystal consists of phenothiazine cation radicals(PT+·) and hexachloroantimonate anions(SbCl6−), and every ion exists as a monomer in the crystal. Each SbCl6− forms a distorted octahedron. The two C–S distances of PT+· are 1.705 and 1.711 Å, and the C–S–C angle is 103.9°. The dihedral angle between the two outer phenyl rings of PT+· is 176.5°. From the ESR measurements of a single crystal, three principal g-values were determined: g1=2.003, g2=2.007 and g3=2.008. The direction of g1 is normal to the molecular plane of PT+·. These facts suggest some π-delocalization in the central ring of PT+·. Absorption spectra polarized parallel to the molecular plane of PT+· are very similar to the poly crystalline reflection spectra of PT+· salts obtained by other authors, and there are no intense bands in the spectra polarized perpendicular to PT+· molecular plane over the wave number range 10 to 27×103 cm−1.
The Formation of Electronically Excited Fragments by the Electron Impact of Furan and Related Five-membered Heterocycles
Authors: Tokue Ikuo , Ikarashi Masami , Takizawa Sadachika , Ito Yoshio
Published: July 2006

In the wavelength region of 200–600 nm, photoemissions from electronically excited H, CH, C2, and CS (only from thiophene and tetrahydrothiophene) were observed when furan, tetrahydrofuran, thiophene, and tetrahydrothiophene were excited by electron impact (0–70 eV). Hydrogen atoms (n=4) and CH(A2Δ) radicals were produced from these five-membered heterocycles via single collision excitations, while CS(A1Π) radicals from thiophene and tetrahydrothiophene were partly formed in secondary processes. The appearance potentials for the hydrogen Balmer β and the CH(A2Δ-X2Π) bands from these five-membered heterocycles are determined, and the dissociation processes forming H(n=4) and CH(A) are discussed.
Chemiluminescence from Reactions of N2*(A3Σu+) with Solid Organic Compounds at 77 K
Authors: Mitsumori Kenichi , Hiraoka Kenzo
Published: July 2006

The luminescence from reactions of N2(A3Σu+) with solid benzene, toluene, hexane, cyclohexane and those doped with biacetyl at 77 K has been investigated. For benzene, a broad band appeared in the range of 350–550 nm whose radiative lifetime was determined to be 2.5 s. This band was largely eliminated by addition of a small amount of biacetyl, indicating the participation of an intermediate excited state in solid benzene, i.e. triplet excitons. The emitter of the broad band was tentatively assigned to reaction products, possibly benzene isomers. For toluene, a strong appearance of benzyl radical emission was observed. With an addition of biacetyl, the elimination of benzyl emission and a strong growth of biacetyl phosphorescence were observed as for the benzene/biacetyl system. With an increase of biacetyl concentration, a remarkable red shift were observed for biacetyl phosphorescence, while no shift was observed for benzyl emission, indicating the difference of the solvent effect for these electronic transitions. No luminescence was observed for solid hexane and cyclohexane.
Magnetic-superexchange Interactions of Uranium(IV) Chloride-addition Complexes with Amides. I
Authors: Miyake Chie , Hinatsu Yukio , Imoto Shosuke
Published: July 2006

Studies of magnetic susceptibility, χ, from 300 to 2 K on seventeen UCl4–amide complexes showed that six complexes had maxima in χ between 155 and 82 K. This unusual magnetic behavior occurred only with N-methyl or ethyl-substituted amide complexes. Infrared and chemical evidence indicates that these six complexes probably have dimeric structure, in which two U(IV) ions are bridged by the amide ligands. Assuming a dimer structure and a two-spin Heisenberg model with −2Jex of about 90 cm−1 for the dimer, the magnetic susceptibilities for the six complexes were calculated in good agreement with the experimental results in the temperature region of the maxima in χ.
Preparation of Trifluoronitrosomethane
Authors: Umemoto Teruo , Tsutsumi Hideo
Published: July 2006

Trifluoronitrosomethane was prepared in a good yield by pyrolysis of nitrosyl trifluoroacetate in a flow of nitrogen monoxide at 190 °C using refluxed perfluorotributylamine as a diluent.
Palladium-catalyzed Reaction of Isoprene with Water in Presence of Carbon Dioxide and Base
Authors: Inoue Yoshio , Sato Michio , Satake Masaki , Hashimoto Harukichi
Published: July 2006

Palladium(0)-catalyzed reaction of isoprene with water was enhanced by the presence of carbon dioxide and a base to give dimethyloctadienols. The same catalyst was found to dehydrate the dimethyloctadienols to afford the corresponding dimethyloctatrienes. The effect of acidity of water on the isoprene-water reaction was also studied.
Acid Decomposition of 5-Amino-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles. A Novel Formation of 1-Amino-2-azabutadienes
Authors: Ito Masato M , Nomura Yujiro , Takeuchi Yoshito , Tomoda Shuji
Published: July 2006

Acid decomposition of 4-alkyl-5-dialkylamino-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles gave N1,N1-dialkyl-N2-vinylalkanamidines, which have 2-aza-1,3-butadiene skelton, in fair yields.
The Reaction of O-Silylated Enolates of Carboxylic Esters and of Lactones with Aminomethyl Ethers Catalyzed by ZnCl2
Authors: Oida Tatsuo , Tanimoto Shigeo , Ikehira Hideyuki , Okano Masaya
Published: July 2006

It was found that the reaction of O-silylated enolates of carboxylic esters and of lactones with aminomethyl ethers proceeds smoothly under a catalytic action of zinc chloride to afford the corresponding α-aminomethylated carboxylic esters or lactones, except only one case using O-silylated enolate of δ-valerolactone, in which the resultant α-aminomethyl-δ-valerolactone is somewhat unstable and undergoes decomposition, leading to the production of α-methylene-δ-valerolactone.
Structures of the [4+2] Bicyclic Adducts from the Diels-Alder Reaction of Methyl Coumalate with Isoprene
Authors: Matsui Takanao , Inoue Takeshi , Nakayama Mitsuru , White James D
Published: July 2006

The preparation of 9- and 8-methyl-9-iodo-3-oxo-2-oxabicyclo[4.4.0]dec-4-ene-6,8-carbolactone and 8-methyl-3-oxo-2-oxabicyclo[4.4.0] deca-4,9-diene-6,8-carbolactone from the adducts (2a and 2b) of methyl coumalate with isoprene confirmed the structures of the regioisomers, 2a and 2b.
Electronic Absorption Spectra and Geometry of Molecular Ions Generated from Stilbene and Related Compounds. III. Radical Ions of (Z)-Stilbene and Its α,β-Dialkyl Derivatives
Authors: Suzuki Hiroshi , Ogawa Keiichiro , Shida Tadamasa , Kira Akira
Published: July 2006

The radical ions of (Z)-stilbene and its α,β-dialkyl derivatives were produced by γ-ray irradiation of the parent compounds in frozen matrices at 77 K, and their geometries were investigated by electronic absorption spectroscopy. While the relaxed geometries of the radical ions of (Z)-stilbene are probably similar to that of the neutral molecule, those of the radical ions of the α,β-dialkyl derivatives are appreciably different from those of the neutral molecules: The torsion angle of the central ethylenic bond is distinctly larger and that of each C–Ph bond is probably smaller in the radical ions than in the neutral molecules. On illumination the radical ions of (Z)-stilbene isomerize to the E isomers, but those of the α,β-dialkyl derivatives do not. A mechanism of the photoisomerization is proposed, and an interpretation of the difference in the photochemical behavior between the unsubstituted stilbene radical ions and the α,β-dialkyl derivatives is given.
The Reactions of the Singlet NH Radicals with C4 Olefins in the Liquid Phase
Authors: Hamada Jun-ichi , Tsunashima Shigeru , Sato Shin
Published: July 2006

The reactions of NH radicals with C4 olefins, trans- and cis-2-butenes, 1-butene, and isobutene, were investigated by the photolysis of hydrogen azide in the liquid olefin at 0 °C and at the temperature of Dry Ice–methanol. Except for nitrogen and ammonia, amines and aziridines were found to be formed in good yield. 2-Butene-1-amine and trans-2,3-dimethylaziridine from trans-2-butene, 2-butene-1-amine and cis-2,3-dimethylaziridine from cis-2-butene, 3-butene-1- and 2-amines and 2-ethylaziridine from 1-butene, and 2-methyl-2-propene-1-amine and 2,2-dimethylaziridine from isobutene. These product formations were successfully explained by the insertion into the C–H bond and the addition to the double bond of olefin by the singlet NH radicals. In the case of 2-butene, no isomerized aziridine formation was observed. This result suggested that the triplet NH radicals rarely add to the double bond of olefin.
Brφnsted Relation for Hydrogen→Deuterium Exchange Reactions of Imidazole-bearing Molecules with Amino Groups
Authors: Endo Toshiya , Shimada Ichio , Inagaki Fuyuhiko , Miyazawa Tatsuo
Published: July 2006

The base-catalyzed hydrogen→deuterium exchange rates of the imidazole C-2 protons were measured for the imidazole-bearing molecules with amino groups (N2H2·Im) in 2H2O at various pH. From the pH dependences of the pseudo-first-order rate constants, the second-order rate constants were obtained for the N2H3+·Im2H+ species and for the equilibrium mixtures of the N2H2·Im2H+ and N2H3+·Im species. For both the N2H3+·Im2H+ and N2H2·Im2H+ species, the second-order rate constants and microscopic dissociation constants of the imidazolium rings were found to satisfy the Brφnsted relation, with concomitant estimation of the abundance ratio of the N2H2·Im2H+ and N2H3+·Im species. This abundance ratio was compared with that estimated from the pH dependence of proton chemical shifts.
Volumetric Study on the 1,3-Dipolar Cycloaddition Reaction of Diazodiphenylmethane with Several Olefins
Authors: Yoshimura Yosuke , Osugi Jiro , Nakahara Masaru
Published: July 2006

A high pressure kinetic study was made of the 1,3-dipolar cycloaddition reaction of Ph2CN2 with dimethyl maleate (DMM), dimethyl fumarate (DMF), methyl acrylate (MA), maleonitrile (MN), fumaronitrile (FN), and acrylonitrile (AN) in toluene at 25 °C. The activation volumes (ΔV\eweq) at 1 bar obtained for DMM, DMF, MA, MN, FN, and AN are −23.4±0.5, −22.3±0.2, −19.8±0.4, −21.5±0.6, −21.0±1.1, and −23.9±0.5 cm3 mol−1, respectively. The reaction volume (ΔV) for the reaction between Ph2CN2 and DMM was determined dilatometrically by taking advantage of supersaturation of the cycloadduct in solution; ΔV=−24.5±0.5 cm3 mol−1 and ΔV\eweq⁄ΔV=0.955. The present volumetric information coupled with a kinetic analysis shows that Firestone’s biradical mechanism is not the case; the concerted mechanism is supported. The experimental result is compared with that of a recent ab initio molecular orbital calculation with respect to the activation and reaction volumes.
Pressure and Temperature Effects on Octahedral-Tetrahedral Equilibria in Pyridine Solutions of Some Cobalt(II) Halides
Authors: Kojima Kazuo , Saida Minoru , Donoue Masami , Matsuda Jiro
Published: July 2006

The visible absorption spectra of CoX2 (X=Cl, Br) in pyridine solutions have been measured in the ranges 1 bar—3 kbar at room temperature, and ≈4—≈70 °C at 1 atm. The equilibrium, [CoX2(py)2](tetrahedral)+2py\ightleftharpoons[CoX2(py)4](octahedral), is found to be followed over these pressure and temperature ranges. High pressure favors the octahedral species, with the volume changes, −41 cm3/mol for the chloride and ≈−30 cm3/mol for the bromide at 1 atm. The pressure dependence of the volume change is less for the bromide than for the chloride. High temperature, however, favors the tetrahedral species, with the heats of reaction, 57.3 and 60.7 kJ/mol for the chloride and the bromide, respectively. Some discussions on both the effects are also presented.
Phase Equilibria in the Nd2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Mizokuchi Chikaaki , Katsura Takashi
Published: July 2006

Phase equilibria in the Nd2O3–V2O3–V2O5 system were established at 1200 °C by changing the oxygen partial pressures from −0.68 (air) to −12.50 in terms of logPO2. In this system, VnO2n−1 (n=2–7), VO2, Nd2O3, NdVO3, NdVO4, 0.81Nd2O3·0.19V2O5 (Nd1.62V0.38O3.38, A), and 3Nd2O3·V2O5 (Nd3VO7, B) were stable under the present experimental conditions. Compounds with Nd2O3/V2O5 mole ratios of 6/1 and 2/1 were not found under the present experimental conditions. Compounds A, Nd3VO7, NdVO3, and NdVO4 have nonstoichiometric compositions. The pattern of the phase diagram is different from those of other Ln2O3–V2O3–V2O5 systems that have previously been established by us. On the basis of the phase diagram, the Gibbs energies of the reactions:

(1) 31⁄50Nd2O3+19⁄50NdVO3+19⁄100O2=Nd1.62V0.38O3.38

(2) 50⁄31Nd1.62V0.38O3.38+12⁄31NdVO3+6⁄31O2=Nd3VO7

(3) NdVO3+1⁄2O2=NdVO4

were determined to be −61.4, −47.4, and −128.9 kJ respectively. In the Nd2O3–V2O3 system, only NdVO3 is stable under the present experimental conditions.
Kinetic Study of the Oxidation of Formate by Iodine in Micellar Solutions of Alkyltrimethylammonium Chlorides
Authors: Hayakawa Katumitu , Kanda Mitsuo , Satake Iwao
Published: July 2006

The spectrophotometric study was made of the oxidation of formate by iodine in micellar solutions of decyl- and dodecyltrimethylammonium chlorides. In the presence of the cationic surfactant micelles, the reaction was found to take place only at the micellar surface according to the same mechanism as in water. The experimental second-order rate constant rose steeply to a maximum at the critical micelle concentration and then decreased monotonously with increasing surfactant concentration. A tentative estimation based on a charged-phase separation model led to the true second-order rate constant in micellar phase of 0.03–0.07 mol−1 dm3 s−1 at 30 °C, which is comparable with that in water. Thus the observed rate enhancement in cationic surfactant solutions can be interpreted in terms of an increase in surface concentration of the formate ion arising from an electrostatic interaction with the micellar ion. The micellar effects on the formation constant of triiodide ion are also discussed.
Mechanism of the Photochemical and Thermal Wolff Rearrangement of 2-Diazo-1,3-dicarbonyl Compounds
Authors: Tomioka Hideo , Hayashi Norihiro , Asano Tsuneo , Izawa Yasuji
Published: July 2006

Thermolysis and photolysis of 2-diazo-1,3-dicarbonyl compounds were investigated as a function of methanol concentration. As the methanol concentration decreased, methyl group migration increased concomitant with the suppression of O–H insertion into methanol, whereas aryl group migration was essentially unaltered with the methanol concentration. The results are interpreted as indicating that aryl migration occurs directly from the excited state of diazo compounds, but that met hyl migration takes place in the singlet carbene in competition with O–H insertion.
Conversions of Carbonyl Compounds via Their Polymeric Sulfonylhydrazones into Alkenes, Alkanes, and Nitriles
Authors: Kamogawa Hiroyoshi , Kanzawa Asami , Kadoya Masahiro , Naito Takeshi , Nanasawa Masato
Published: July 2006

Reins consisting of cross-linked poly(styrene-divinylbenzene) matrices functionalized with hydrazinosulfonyl groups react with aldehydes and ketones to form the sulfonylhydrazone derivatives. The extent of the reaction is sensitive to the type of resin and the bulk of the carbonyl compound. When heated strongly under alkaline conditions, the sulfonylhydrazones release the corresponding alkenes; upon the NaBH4 or LiAlH4 treatment, they also release the corresponding alkanes; and, upon refluxing in methanol with potassium cyanide, they release nitriles containing one additional carbon atom.
Coenzyme Models. 33. Evidence for Retro-acyloin Condensation as Catalyzed by Thiazolium Ion and Cationic Micelle. Oxidative Trapping of the “Active Aldehyde” Intermediates by Flavin
Authors: Shinkai Seiji , Hara Youichiro , Manabe Osamu
Published: July 2006

N-Hexadecylthiazolium bromide(HxdT) in the CTAB micelle, which is known as an excellent catalytic system for acyloin condensation of aldehydes, catalyzes the reverse reaction (i.e., retro-acyloin condensation) to give aldehydes from α-ketols via the active aldehyde intermediates. The existence of the novel, HxdT-mediated process was proposed on the basis of an experimental discovery that flavin (3-methyltetra-O-acetylriboflavin: MeFl), which is capable of oxidatively trapping the active aldehyde intermediates, is reduced by α-ketols such as acetoin and 3-hydroxy-3-methyl-2-butanone in the micellized HxdT solution. It was further substantiated by detection of acetaldehyde in the final reaction mixture. Based on the disappearance rate of the absorbance of MeFl, we spectrophotometrically estimated the rate constants for the retro-acyloin condensation. Similarly, biacetyl, the monohydrated species of which is analogous to α-ketol, afforded acetaldehyde and acetic acid in the micellized HxdT solution, the rate constant being greater by factors of 102–103 than those for α-ketols. The relevance of the retro-acyloin condensation to biological systems (e.g., the mechanism of transketolase catalysis) is discussed.
The Hydroxylation of β-Terpineol and Its Acetate with the Cultured Cells of Nicotiana tabacum
Authors: Suga Takayuki , Lee Ym Sook , Hirata Toshifumi
Published: July 2006

The biotransformation of c-4-p-menth-8(9)-en-r-l-ol (β-terpineol) and its acetate with the cultured suspension cells of Nicotiana tabacum were tested. It was found that the cultured cells have the ability to hydroxylate not only the allylic positions of the C–C double bond of these substrates, but also their terminal carbon-carbon double bond. The hydroxylation at the 4-position of their allylic positions was stereospecific, affording a trans-1,4-diol.
The Ion-exchange Chromatography of Imino Derivatives of Glycine
Authors: Kawashiro Katsuhiro , Morimoto Shiro , Yoshida Hideyuki
Published: July 2006

The resolution of the six imino derivatives of glycine (Gly) by ion-exchange chromatography is described. The imino compounds included iminodiacetonitrile (1), iminodiacetamide (2), iminodiacetic acid (3), α-(cyanomethylamino)acetamide (4), α-(cyanomethylamino)acetic acid (5), and α-(carbamoylmethylamino)acetic acid (6). A mixture of 1–6 was chromatographed along with Gly, glycinamide, aminoacetonitrile, and NH3 with an automatic amino acid analyzer using Aminex A-4 resin column (0.25φ×50 cm) and sodium citrate buffers. When the initial buffer of pH 3.25 was changed to pH 6.50 15 min after beginning the analysis, these ten components were completely resolved. The analysis was completed in about 4.5 h. The stability of 1, 4, and 5 in aqueous media at room temperature was also studied.
Anion-catalyzed Phase-transfer Catalysis. I. Application to Diazo-coupling Reactions
Authors: Iwamoto Hidetoshi , Yoshimura Masaji , Sonoda Takaaki , Kobayashi Hiroshi
Published: July 2006

Anion-catalyzed phase-transfer catalysis was evidenced in the diazo-coupling reactions of the arenediazonium ion with a range of diazophile components in liquid-liquid- and liquid-solid two-phase systems. The tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ion was effective as an anionic catalyst to accelerate the reactions. Comparisons of the reaction rates in the two-phase system with those in solution systems indicated that the acceleration was due to the increased activity of the cationic reagent, partly by solubilization and partly by the dehydration of such cationic species in the nonpolar organic phase.
Restricted Rotation Involving the Tetrahedral Carbon. XLVII. The “Positive” and the “Negative” Buttressing Effects on the Rotational Barriers in 9-(1,1-Dimethyl-2-phenylethyl)-1-halotriptycenes
Authors: Yamamoto Gaku , Suzuki Masahiko , Oki Michinori
Published: July 2006

9-(1,1-Dimethyl-2-phenylethyl)-1,2,3,4-tetrahalotriptycenes (halogen=F, Cl, and Br) were synthesized and the kinetic studies of the rotational isomerization were made. The obtained data were compared with those for the corresponding 1-halo derivatives. The equilibrium constants (±sc⁄ap) for the tetrahalo compounds are smaller than those for the respective monohalo counterparts. The tetrafluoro compound isomerizes twice slower than the monofluoro one at 240 °C, showing the “positive” buttressing effect. Contrarily, the tetrachloro and the tetrabromo compounds isomerize 13 and 100 times, respectively, faster than the corresponding monohalo compounds at 175 °C, exhibiting the “negative” buttressing effect. These intriguing phenomena are discussed in terms of the molecular deformation in these congested compounds, which affects both the ground state and the transition state for rotation.
Acyl Transfer from S-Monoacyldihydrolipoamide to Benzylamine in the Presence of Oxidizing Agents
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto
Published: July 2006

Acyl transfer reaction from N-benzyl-8-S-(p-nitrobenzoyl)dihydrolipoamide to benzylamine was enhanced with oxidizing agents such as cobalt(II) ion or a soluble flavin under an oxygen atmosphere or with di-4-pyridyl disulfide, accompanied by the formation of N-benzyllipoamide.
31P NMR Study of Active Species for Ethylene Dimerization in σ-Aryl Nickel Complex–AgClO4
Authors: Ishimura Yoshimasa , Maruya Ken-ichi , Nakamura Yoshiyuki , Mizoroki Tsutomu , Ozaki Atsumu
Published: July 2006

[NiBr(σ-C6F5)(PPh3)2] and [NiCl(σ-C6Cl5)(PPh3)2] are active for ethylene dimerization in the presence of AgClO4. The activity increases with increase in the amount of AgClO4 and reaches maximum at AgClO4/Ni-complex=2. Addition of excess AgClO4 leads to marked decrease in activity with [NiBr(σ-C6F5)(PPh3)2] but a little decrease with [NiCl(σ-C6Cl5)(PPh3)2]. 31P NMR spectra of the active solution showed new resonance peaks due to [Ni(ClO4)(σ-C6X′5)(PPh3)2] and [Ni(ClO4)(σ-C6X′5)(PPh3)] (X′=F,Cl), accompanying formation of AgX (X=Br,Cl) and [Ag(ClO4)(PPh3)]. Thus the role of AgClO4 is to abstract halide anion and/or triphenylphosphine. The amount of Ni(ClO4)(σ-C6X′5)(PPh3)] is in good correlation with the rate of dimerization, which suggests this species to be catalytically active.
The ESR Spectrum of a π Cation Radical Trapped in a Single Crystal of Chloro(tetraphenylporphyrinato)cobalt(III)
Authors: Kohno Masahiro , Ohya-Nishiguchi Hiroaki , Yamamoto Kiyoko , Sakurai Tosio
Published: July 2006

The electron-spin-resonance (ESR) spectra of three paramagnetic species trapped in single crystals of chloro(tetraphenylporphyrinato)cobalt(III) have been observed at 77 K. Using the ESR parameters obtained, one of them has been identified as the [CoIII(tpp)]2+·(Cl−)2 π cation radical, and the other two species, as [CoII(tpp)] which are influenced by axial ligation. From the angular variations in the hfcc due to the 59Co, 14N, and 35Cl in the π cation radical, it has been found that the unpaired electron resides on the a2u porphyrin π orbital and polarizes the Co and Cl atomic orbitals through a spin-polarization mechanism. Finally, the radical formation mechanisms in solution are briefly discussed, based on the results obtained from the single-crystalline measurements.
A Comparison between Ruthenium and Palladium with Regard to the Chemisorption of Carbon Monoxide on Metal Clusters Using Molecular Orbital Calculations
Authors: Kobayashi Masahiro
Published: July 2006

Self-consistent charge extended Hückel calculations for systems consisting of 1–3 CO molecules chemisorbed on 8-atom and 10-atom clusters of Ru and Pd are reported. The binding energies and overlap populations between Pd and C are always smaller than those between Ru and C. It was found that the multiple types of bondings between 2–3 CO and a surface metal atom were less stable for Pd than for Ru.
Electronic Structure and Spectra of Organic Dye Anions of Uranine and Eosin Y
Authors: Hirano Koichi
Published: July 2006

The excited states of the organic dye anions of Uranine and Eosin Y are invesitigated by the semi-empirical SCF-MO-CI calculations. The two-center core integral values of the C–Br bond (−0.20 eV) were determined. Agreement between the calculated and observed spectra was satisfactory. The first intense bands of these dye anions can be assigned to the HOMO→LUMO transition band arising from the local excitation of xanthene ring. The second bands are interpreted as the overlap of the two transition bands for the xanthene ring and for the residual π-systems.
Photochemistry of Metal-Metal Bonded Compounds. I. Isolation and X-Ray Molecular Structure Analyses of Orthometalated Triphenyl Phosphite Manganese Carbonyl Derivatives and Reaction Mechanisms of Orthometalation from Photodegradation of Manganese Carbonyl Derivatives with Sn–Mn Bond
Authors: Onaka Satoru , Kondo Yoshinori , Furuichi Nobuhiro , Toriumi Koshiro , Ito Tasuku
Published: July 2006

Photochemical degradation of a series of tin-manganese bonded complexes was studied. The apparent reactivity of the tin-manganese bond toward UV irradiation is interpreted on the basis of absorption spectra of relevant complexes and available emissions from the light source. Two kinds of orthometalated products were obtained from photolysis of Me3Sn–Mn(CO)3[P(OPh)3]2 in benzene. Various kinds of experiments suggest that their photochemical reactions proceed through homolytic cleavage of the Sn–Mn bond in the initial stage and the resulting 15-electron intermediates abstract hydrogen from the triphenyl phosphite moiety. Molecular structures of the two kinds of orthometalated products, as clarified by X-ray structure analyses, are described.
The Formation of Needle-like Particles of xCoFe2O4·(1−x)Fe3O4 with x≤0.2
Authors: Kiyama Masao , Takada Toshio
Published: July 2006

An experimental study was made of the oxidation with air of alkaline suspensions containing needle-like Fe3O4 particles and slight amounts of Co1⁄3/Fe2⁄3(OH)2 at temperatures between 60 and 90 °C, together with the properties of the resulting oxidation products. It has been found that the Hc (coercivity) values of the products were greatly affected by both the excess NaOH concentration and the oxidation temperature—i.e., the two essential factors in determining the difference in the properties of a cobalt ferrite layer coated on the Fe3O4 particles, that these values increased with the heat treatment in vacuo of the products within the temperature range of 200 to 450 °C, without decreasing the saturation magnetization values, and that the Hc increment was mainly governed by the Co content.
Potentiometric Study of Heteropolyanion Formation from Dimethylarsinate and Molybdate Anions in Acidic Aqueous Solution
Authors: Takahama Hironobu , Sasaki Yukiyoshi
Published: July 2006

The equilibria, pH++qMoO42−+r(CH3)2AsO2−=(H+)p(MoO42−)q[(CH3)2AsO2−]r were studied by the use of a glass electrode in 1 M Na(Cl) ionic medium at 25 °C. The data were explained by assuming two heteropolyanions of the compositions, (p,q,r)=(6,4,1) and (7,4,1) with the formation constants logβ6,4,1=39.8±0.02 and logβ7,4,1=46.03±0.01.
Mössbauer Studies of Thermal Decomposition of Hexaamminecobalt(III) Hexacyanoferrate(III) and Hexaamminecobalt(III) Hexachloroferrate(III) in Air and in Nitrogen Atmosphere
Authors: Brar Ajaib Singh , Brar Sarvjit , Sandhu Sarjit Singh
Published: July 2006

Thermal decomposition of hexaamminecobalt(III) hexacyanoferrate(III) (1) and hexaamminecobalt(III) hexachloroferrate(III) (2) in air as well as in nitrogen atmosphere was studied by using Mössbauer spectroscopy, TGA, DTA, IR spectroscopy, and magnetic susceptibility measurement. 1, when heated in air, is stable up to 200 °C and then converted into hexacyanoferrate(II) and finally to ferrites; in inert atmosphere iron metal and carbides are formed above 400 °C. 2 in air is reduced to iron(II) species and finally to ferrites; in inert atmosphere ligand exchange takes place forming cobalt(II) chloride. A mechanism is proposed for the decompositions of 1 and 2.
Analytical Extraction of Uranium with TOPO from Sea Water
Authors: Degetto Sandro , Faggin Mario , Moresco Anna , Baracco Livio
Published: July 2006

A distribution study was carried out on the extraction behaviour of uranium in sea water using solutions of TOPO in cyclohexane. The influence of various factors (time, pH, TOPO concn in the organic phase, nitrate or chloride concentration in the aqueous phase and volumetric ratio between the two phases) on the extractability of uranium was investigated. In view of the results obtained, the best conditions for a quantitative recovery were selected. The application of the results to fluorimetric determination of uranium is also reported.
A Kinetic Study on the Oxychlorination of Benzene
Authors: Blanco Jesus , Avila Pedro , Melo Francisco Vicente
Published: July 2006

Gas-phase benzene oxychlorination was carried out over a CuCl2–CeCl3/Al2O3 catalyst. A kinetic model is proposed which permits us to obtain a rate equation capable of reproducing experimental results. The presence of cerium in the catalyst increases the reaction rate and maintains the conversion level for a long time. It seems that this element facilitates copper reoxidation by making the total rate independent of the partial pressure of oxygen and stabilizes the active phase of the catalyst.
Barium Manganate. A Versatile Oxidant in Organic Synthesis
Authors: Firouzabadi Habib , Mostafavipoor Zohreh
Published: July 2006

Preparation of barium manganate in large-scale is discussed. It is also shown that this reagent is capable of oxidizing organic substrates, converting alcohols to their corresponding carbonyl compounds, aromatic amines to their corresponding azo compounds, hydroquinone to p-benzoquinone, benzylamine to benzaldehyde, and triphenylphosphine to its oxide in good yields. Saturated hydrocarbons, unsaturated hydrocarbons, unsaturated ketones, and saturated amines are not affected by this reagent in a reasonable reaction time.
Laser Stark Spectroscopy of AsH3 Using 9.4 and 10.6 μm CO2 Laser
Authors: Nakagawa Kuniaki , Ueda Yoshifumi , Kuchitsu Kozo
Published: July 2006

Perturbation-allowed transitions of the v2 and v4 bands of AsH3 were observed. About 100 Stark components were assigned to six Δ(k-l)=0, six Δ(k-l)=±3, and three Δ(k-l)=±6 transitions. The Stark patterns and hyperfine splittings were used for confirming the assignment.
Production of Hydrogen by Photochemical Splitting of Water Using Diammonium Tetrathiomolybdate as Photocatalyst
Authors: Bhattacharya A , Basu J , Das K , Bhattacharyya R G , Chatterjee A B , Rohatgi-Mukherjee K K
Published: July 2006

Hydrogen gas is generated at the cathode when the anode compartment of a photogalvanic cell anode/(NH4)2MoS4(aq, satd.)//5M HCl (aq)/cathode is illuminated. The photocurrent generated rises slowly with time and reaches a limiting value. A mechanism is suggested involving the conversion of Mo(VI) to Mo(V) and the formation of OH radicals, as evidenced by development of paramagnetism on irradiation. Although the photocatalyst is susceptible to hydrolysis, it can be easily regenerated by passing H2S.
Properties of Alkali-free Magnesium Phosphate Glass Membranes Containing Silver Oxide and Their Application to the Ammonia Selective Electrode
Authors: Nomura Tsuyoshi , Nakagawa Genkichi
Published: July 2006

The properties of magnesium phosphate glass and the potential response of its membrane to ammonia were studied. The most suitable glass composition for the ammonia selective electrode is 5Ag2O–50P2O5–40MgO–5Al2O3. The potential-concentration curve of the electrode exhibits a slope of about 48 mV/decade for the ammoniaconcentration range of (10−2–10−6) mol/dm3.
The Solvent Extraction-Spectrophotometric Determination of Perchlorate Ions with Monoethynolog of Malachite Green
Authors: Akiyama Shuzo , Nakashima Kenichiro , Nakatsuji Shin’ichi , Hamada Makiko , Izaki Yayoi
Published: July 2006

By the use of a new reagent, 1,1-bis(p-dimethylaminophenyl)-3-phenyl-2-propynylium chloride, i.e., one of the ethynologs of Malachite Green, micro amounts of perchlorate ions could be extracted into chlorobenzene and determined spectrophotometrically. Beer’s law holds over the range of 4×10−6–2.5×10−5 M (M=1 mol dm−3); ε=4.0×104 dm3 mol−1 cm−1 at 690 nm.
The Crystal Structure of the 1-(2-Carboxyethyl)uracil : Phenethylamine(1:1) Complex
Authors: Ishida Toshimasa , Yamamoto Keizo , Inoue Masatoshi
Published: July 2006

The crystal of the title complex is monoclinic, with a space group of Cc, a=5.678(1), b=33.814(7), c=8.058(2) Å, β=103.42(1)°, and Z=4. The two component molecules are linked to each other by hydrogen bonds between the amino and carboxyl groups. No prominent interaction was observed between benzene and uracil rings.
Primary Structure and Molecular Evolution of Intestinal Calcium-binding Protein
Authors: Iida Yôichi
Published: July 2006

The primary structure and the molecular evolution of protein were examined with bovine and porcine intestinal calcium-binding protein (ICaBP). The amino acid sequence of this protein was compared with that of ancestral calmodulin, which had been predicted as the most ancient form in the family of calcium-binding proteins.
Phase Behavior and Tricritical Phenomena in a Bile Salt System
Authors: Kunieda Hironobu , Shinoda K\={o}z\={o}
Published: July 2006

A three-phase region consisted of a water (W), a surfactant (D) and an oil (O) phases was found in a sodium taurocholate (NaTC)/brine/co-surfactant (monoglyceride or its model compound)/oil (triglyceride) system. A required concentration of cosurfactant to produce the three-phase region was decreased with increasing salinity. The three-phase region becomes narrower and finally vanishes with decreasing salinity at constant temperature or with the rise in temperature at constant salinity in a NaTC/brine/glycerol mono (2-ethylhexyl) ether/glycerol tris (2-ethylhexanoic) ester system. Since the critical end points of O–D and D–W phases approach and coincide in the system, the three-phase region disappears at a tricritical point at which three coexisting liquid phases become identical. According to the phase rule, there is a line of tricritical points in the space of T and compositions in this five-component system and it moves toward higher temperatures with the increase in salinity. Therefore, the three-phase region exists at temperatures below the tricritical temperature at constant salinity.