Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 78 , Issue 12
Showing 1-24 articles out of 24 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for Young Chemists for 2004
  • Akimitsu Okamoto
    2005 Volume 78 Issue 12 Pages 2083-2097
    Published: 2005
    Released: December 09, 2005
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    We have synthesized a number of highly functional nucleic acids and have applied them to DNA technology. Unique characteristics possessed inherently by DNA have been applied to the design of highly functional nucleic acids. We spatially arranged functional bases in the nucleic acid structure, and controlled various functions of the synthetic nucleic acids by changes in sequence, microstructure, and micropolarity. The organic synthesis of such conceptually new functional nucleic acids could open up a new field of genome science and nanobiomaterial science. In this review, we describe the following: (i) rational design of highly functional DNA nanowires, (ii) the development of base-discriminating fluorescent nucleobases and their application to gene polymorphism typing, and (iii) reporter nucleobases for monitoring the change in the microenvironment around DNA and its surroundings.
BCSJ Award Article
  • Tsuyoshi Yamaguchi, Takahiro Kiuchi, Tatsuro Matsuoka, Shinobu Koda
    2005 Volume 78 Issue 12 Pages 2098-2104
    Published: 2005
    Released: December 09, 2005
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    A generalized ensemble Monte Carlo simulation method that enables one to simulate open systems under various chemical potentials in a single run is applied to the pH titration of weak polyelectrolytes. The free energy profile has a double-minimum structure as the function of the ionization degree in poor solvents, indicating the change in the ionization degree that resembles a first-order phase transition. The two minima correspond to the less-charged globular state and the charged coil state. The structures of the polymer in the instable region of the ionization degree are investigated in detail. Results show that the conformation of the transition state consists of one blob and one or two strings. In addition to the structural inhomogeneity, a heterogeneous distribution of the charge is found there.
Articles
  • Naser Seyed Matin, Amir Hossein Jalili
    2005 Volume 78 Issue 12 Pages 2105-2113
    Published: 2005
    Released: December 09, 2005
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    The results of a molecular-dynamics simulation using various isotropic pair potential functions for pure methane, oxygen, and their binary mixtures in the temperature range of 200 to 600 K and densities up to about 1.5 times their critical density is presented. The models studied in this work were: 1) Lennard–Jones (12–6) potential functions with different parameters, which have been proposed for methane and oxygen in the literature, 2) various types of Mie(nm) potential with different values of n and m, for both methane and oxygen molecules, and 3) a potential function introduced by Dymond, Rigby, and Smith (DRS model). A Kihara–Mie(20–6) potential with the best value for the Kihara parameter, “γ” and optimized σ and ε is proposed for an oxygen molecule. Considering the predicting capability of the mentioned potential functions for pure methane and oxygen, two of them were selected for investigating methane–oxygen binary mixtures. The CH4–CH4 and O2–O2 center-of-mass radial distribution function, calculated with selected potentials, predicts the positions and peak height for g(r)CH4–CH4 and g(r)O2–O2 in good agreement with experimental data. The Deiters equation of state was used for PVT data production of pure methane and oxygen and their mixtures via imposing an intuitive mixing rule for the equation-of-state parameters. The results show good agreement between the LJ(12–6) and DRS potential models and the Deiters equation of state at densities of up to 0.25 g mL−1 at all temperatures, the deviations increasing by increasing the density. Furthermore, in the case of a methane–oxygen binary mixture, the Peng–Robinson equation of state was applied. The results reveal a strong influence of the binary interaction parameter, over the predicting ability of the Peng–Robinson equation of state for the mixture under study.
  • Kazuo Mukai, Daisuke Shiba, Kenji Yoshida, Kyohei Mukai, Hiroyuki Hisa ...
    2005 Volume 78 Issue 12 Pages 2114-2123
    Published: 2005
    Released: December 09, 2005
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    Four kinds of 1:1 salts of 3-(4- and 3-alkyl-pyridinium)-1,5-diphenylverdazyl (alkyl = ethyl and methyl) radical cations with the Ni(dmit)2 anion ([p-EtPyDV]+[Ni(dmit)2] (1), [m-EtPyDV]+[Ni(dmit)2] (2), [p-MePyDV]+[Ni(dmit)2] (3), and [m-MePyDV]+[Ni(dmit)2] (4)) have been prepared. The magnetic properties of salts 14 were discussed based on the results obtained by magnetic susceptibility and ESR measurements of 14 and the crystal structure analysis of 1. The results of the crystal structure analysis of salt 1 indicate the dimer formation in Ni(dmit)2 anion molecules, and the dimers are sandwiched between two verdazyl cations [p-EtPyDV]+, indicating the formation of a magnetic linear tetramer in 1. The magnetic susceptibility data for salt 1 have been fitted to a four-spin linear tetramer model using an end exchange interaction of 2J1/kB = −780 K and a central interaction of 2J2/kB = −200 K. The conductivity (σ) of salts 1, 2, 3, and 4 at room temperature was σ = 2.3 × 10−5, 1.8 × 10−4, 1.4 × 10−5, and 5.4 × 10−6 S cm−1 with an activation energy of EA = 0.28, 0.52, 0.21, and 0.33 eV, respectively. The 1:1 salts 14 are new molecular paramagnetic semiconductors.
  • Keiko Miyamoto, Keiko Takano, Yutaka Fukuda
    2005 Volume 78 Issue 12 Pages 2124-2129
    Published: 2005
    Released: December 09, 2005
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    Density functional theory, B3LYP/CEP-31G calculations, were performed on nickel(II) complexes comprising N,N,N′,N′-tetramethylethylenediamine (tmen), benzoylacetonate (bzac), and a halide anion (X), Ni(tmen)(bzac)X·n(H2O) (n = 1–4, X = Cl, Br, and I). Fully optimized geometries of [Ni(bzac)2(tmen)], [NiCl(bzac)(tmen)(H2O)], and [Ni(bzac)(tmen)(H2O)2]+ are all in good agreement with crystallographic data. This series of nickel(II) complexes shows a disproportionation reaction in a non-polar and rather inert solvent, such as 1,2-dichloroethane and acetone, accompanied by highly contrasting color changes of the solutions. Also, the presence of an intermediate compound has been confirmed. A possible reaction mechanism of this reaction as well as the structure of the intermediate compound are discussed.
  • Ying Shih, Annamalai Senthil Kumar, Jyh-Myng Zen, Jaw-Cherng Hsu
    2005 Volume 78 Issue 12 Pages 2130-2134
    Published: 2005
    Released: December 09, 2005
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    Due to the severe toxic effects of mercury (Hg) and its derivatives, they are strictly prohibited to be used as cosmetics ingredients. Nevertheless, unknown quantities of Hg are formulated in consumer cosmetic products. We demonstrate a disposable screen-printed electrode modified with 1,5-dibromopentane partially (7%) cross-linked poly(4-vinylpyridine) (SPE/pcPVP) system for the detection of hidden concentrations of mercury, [Hg] within cosmetics goods by anodic stripping analysis in 0.01 M KCl + 0.02 M H2SO4 (1M = 1mol dm−3) solution. The Hg2+ ion in a chloride medium transforms to [HgCl4]2−, which then selectively preconcentrate and electro-deposite as metallic mercury, Hg0 on the cationic SPE/pcPVP (PVP exist as PVP+ in pH < 5). Under optimal conditions, the calibration graph is linear in the window of 25–150 ppb, with a detection limit (S/N = 3) and regression coefficient of 3.21 ppb and 0.9909 respectively for the SPE/pcPVP. Real sample assay results for the three skin-lightening agents are evidence of the precise existence of prohibited Hg (compared with ICP-MS measurements) in the products. This article further cautions the public of Hg toxicity in cosmetics. Since the approach is low cost and disposable, it is highly suitable for unskilled electrochemists.
  • Titus A. M. Msagati, Mathew Muzi Nindi
    2005 Volume 78 Issue 12 Pages 2135-2141
    Published: 2005
    Released: December 09, 2005
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    A supported liquid membrane has been used as a sample clean-up and/or enrichment technique in the recovery of a mixture of aminoglycoside compounds from cow’s milk and urine. The aminoglycoside compounds studied include, neomycin, gentamycin (mainly gentamycin C1a), and streptomycin. The supported liquid membrane (SLM) used to trap these compounds consisted of (1:1) 1-decanol:n-undecane. Several factors affecting the extraction efficiencies during SLM enrichment, such as donor and acceptor phases pHs, were studied. High performance liquid chromatography coupled to a positive ion electrospray-mass spectrometer was used as a detection method for these antibiotic compounds with their minor structural components. The extraction efficiencies obtained after SLM enrichment ranged between 60–90% for milk samples and 80 – ∼100% for urine matrices. The detection limits obtained from urine was 0.23 μg L−1 for neomycin, 0.31 μg L−1 for gentamycin, and 0.16 μg L−1 for streptomycin and from cow’s milk were 0.34 μg L−1 for neomycin, 0.42 μg L−1 for gentamycin, and 0.20 μg L−1 for streptomycin.
  • Hirotoshi Nakabayashi, Yoritsugu Shino, Junya Kobayashi
    2005 Volume 78 Issue 12 Pages 2142-2145
    Published: 2005
    Released: December 09, 2005
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    ZnO–SiO2 binary oxides prepared by the sol–gel method were calcined at various temperatures in order to reveal the relations between the surface properties as an acid–base catalyst and the bulk structures measured by X-ray diffraction. It was found that the acid amount and strength as well as the catalytic activity increased remarkably when the Zn2SiO4 phase was formed exclusively by the reactions between ZnO and SiO2 particles at 1173 K. Changes in the bulk structures were suggested to affect the surface properties of the oxide particles.
  • Hisanori Imura, Tatsunori Namai, Ken-ichiro Ishimori, Sumiko Hayashi, ...
    2005 Volume 78 Issue 12 Pages 2146-2151
    Published: 2005
    Released: December 09, 2005
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    The synergistic extraction of aluminium(III) and gallium(III) with 2,4-pentanedione (Hacac) in heptane from a weakly acidic solution was investigated in the presence of 3,5-bis(trifluoromethyl)phenol (BTMP). A large enhancement of the extraction of metal(III) was ascribed to the formation of outer-sphere complexes between metal(III) chelates and BTMP in the organic phase. Furthermore, an IR study demonstrated that the outer-sphere complexes were formed by the hydrogen bond between the hydroxy hydrogen atom of BTMP and the oxygen atoms of metal(III) chelates. The formation constants of the outer-sphere complexes with BTMP were determined and compared with those with 3,5-dichlorophenol (DCP) to understand the steric effect of the phenol derivative in this synergistic extraction. The bulky trifluoromethyl-group of BTMP and the short oxygen–oxygen nonbonded distance of Al(acac)3 resulted in a steric repulsion between two BTMP molecules to prevent the formation of Al(acac)3·3BTMP, although Al(acac)3·3DCP, Ga(acac)3·3BTMP, and Ga(acac)3·3DCP could be formed. Such a steric effect on outer-sphere complexation improves the separation efficiency between aluminium(III) and gallium(III) in the present synergistic extraction.
  • Takahiko Kojima, Ken-ichi Hayashi, Yoshihito Shiota, Yoshimitsu Tachi, ...
    2005 Volume 78 Issue 12 Pages 2152-2158
    Published: 2005
    Released: December 09, 2005
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    Ruthenium(II)–acetonitrile complexes having pentadentate tris(2-pyridylmethyl)amine (tpa) derivatives with coordinated amide CO groups were prepared and characterized by various spectroscopic methods, electrochemical measurements, and DFT calculations. The acetonitrile ligand was indicated to tightly bind to the ruthenium(II) center in an η1-N fashion. The Mulliken charge distribution, obtained by a calculation, indicated that the ruthenium(II)–nitrile bond is more covalent than other coordination bonds of the tpa moiety. The redox potentials of Ru centers and the chemical shifts of methyl groups of the acetonitrile ligands exhibited a linear relationship, indicating that electron density of the Ru center controls that of the acetonitrile ligand. Those complexes showed fluxional behavior in CD3CN solutions to exhibit one mode of thermal motion; it also altered the symmetry of the complexes.
  • Masahiro Ebihara, Naohiro Kanematsu, Masako Yoshida, Takashi Kawamura
    2005 Volume 78 Issue 12 Pages 2159-2160
    Published: 2005
    Released: December 09, 2005
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    Iridium(III) dinuclear complexes with thioacetato bridges and dithioacetato chelates were prepared by the reaction of H2IrCl6·6H2O with a mixture of Li2CO3, MeCOSH, MeCO2H, and (MeCO)2O under O2. X-ray structures of two geometrical isomers for [{Ir(S2CMe)2}2(μ-SOCMe)2] were determined.
  • Hai-Ying Jin, Ryoichi Hazama, Mikio Yamasaki, Keisuke Umakoshi, Kiyosh ...
    2005 Volume 78 Issue 12 Pages 2161-2163
    Published: 2005
    Released: December 09, 2005
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    Chiral distortion of the basal four pyridyl nitrogen donors of the titled complex [Mo2(O)2(μ-S)2{μ-N,N,N′,N′-tetrakis(2-pyridylmethyl)-R-propylenediamine}]2+ has been found to be the reverse to that of the corresponding di-μ-oxo complex, on the basis of the inverse pattern of the circular dichroism spectra. Asymmetric distortion of the dimolybdenum(III) dimer [Mo2(μ-OH)2(μ-CH3COO){μ-N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine}]3+ has also been discussed.
  • Masayuki Kobayashi, Takayuki Saito, Kiyomichi Takahashi, Zheng-Yu Wang ...
    2005 Volume 78 Issue 12 Pages 2164-2170
    Published: 2005
    Released: December 09, 2005
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    The electronic properties of soluble redox proteins from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium (T.) tepidum have been studied in terms of electronic absorption, magnetic CD, midpoint redox potential, and electron-transfer behavior. T. tepidum possesses one high potential iron–sulfur protein (HiPIP), one cytochrome c’, and two low potential cytochrome c-552’s. The two low potential cytochrome c-552’s can be separated further into a higher and a lower potential species. The HiPIP has a midpoint redox potential of +340 mV at pH 7. From electron-transfer ability shown by flash experiments, the HiPIP was confirmed to be the possible electron-transfer protein to the reaction center under physiological conditions. The HiPIP is thermally stable up to 60 °C, which is much higher than that of the mesophilic photosynthetic bacterium, Allochromatium (A.) vinosum. Cytochrome c’ has a high-spin protoheme with a redox midpoint potential of +100 mV at pH 7, similar to those of many other photosynthetic bacteria. The molecular weight was determined to be 14147 Da by MALDI-TOF/MS experiments. The higher potential cytochrome c-552’s have hemes c’s with midpoint redox potentials of −15 and +85 mV, and the lower one of −15 mV. The molecular weights for the higher potential cytochrome c-552 and the lower potential c-552 were found to be 20702 and 47757 Da, respectively. The higher potential cytochrome c-552 has an attached flavoprotein with a molecular mass of 42000 Da. The lower potential cytochrome c-552 has been found for the first time in T. tepidum.
  • Kazuhiro Kobayashi, Yusuke Izumi, Kazutaka Hayashi, Osamu Morikawa, Hi ...
    2005 Volume 78 Issue 12 Pages 2171-2174
    Published: 2005
    Released: December 09, 2005
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    A convenient synthesis of 11H-indolo[3,2-c]quinolines carrying a substituent, such as 1-hydroxyalkyl, 1-alkoxyalkyl, or 1-(dialkylamino)alkyl, at the 6-position by electrophile-mediated cyclization reactions of 2-(2-isocyanophenyl)-1-methyl-1H-indole is described.
  • Toshinobu Korenaga, Yusuke Kawauchi, Takahiro Kosaki, Tadashi Ema, Tak ...
    2005 Volume 78 Issue 12 Pages 2175-2179
    Published: 2005
    Released: December 09, 2005
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    A molecular tweezer having two bidentate pentafluorophenyl (C6F5) groups was synthesized, and the π–π stacking ability of the C6F5 groups toward benzene derivatives in a polar organic solvent was evaluated. The structure of the molecular tweezer was revealed to be dimeric in the crystalline state by X-ray analysis. Association constants (Ka) between the molecular tweezer and aromatic guests in THF were found to be roughly correlated with the quadrupole moment (Qzz) of the guests, suggesting that the quadrupole–quadrupole contribution plays a significant role in the π–π interaction even in a polar organic solvent.
  • Hideki Okamoto, Mami Kohno, Kyosuke Satake, Masaru Kimura
    2005 Volume 78 Issue 12 Pages 2180-2187
    Published: 2005
    Released: December 09, 2005
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    The novel azacrowned phthalimide 1 has been prepared and its fluorescence properties have been investigated by addition of EtOH and Ag+. The phthalimide 1 showed appreciable solvatofluorochromism; its fluorescence maxima (λFL) appeared in the wavelength region between 458 (in Et2O) and 544 nm (in EtOH). In benzene, the phthalimide 1 gave off blue emission (λFL 466 nm) while it emitted green fluorescence (λFL 497 nm) upon addition of 250 mM of EtOH. Both the blue and the green emissions were quenched by Ag+. Potential logic operations of the phthalimide 1 were examined using fluorescence outputs at 450 (Out1) and 515 nm (Out2) and two input stimuli, EtOH (In1) and Ag+ (In2). The Out1 was on in the absence of these inputs while its intensity was reduced (off) by either or both of the inputs to serve as a NOR operator. The Out2 was off without the inputs; in contrast, the intensity of Out2 was enhanced (on) by In1. The enhanced Out2 was switched off by In2. The Out2, thus, corresponds to an INHIBIT operation responding to the input signals. The crowned phthalimide 1 mimics a two-input–two-output combinational logic gate with a single fluorophore and a single ion-sensing unit.
  • Yoshiyuki Kuwatani, Gaku Yamamoto, Masaji Oda, Masahiko Iyoda
    2005 Volume 78 Issue 12 Pages 2188-2208
    Published: 2005
    Released: December 09, 2005
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    Tetraaryl[5]cumulenes react with low-valent nickel complexes at the second double bond to produce novel [4]radialene derivatives that are head-to-head dimers of [5]cumulenes. The head-to-head dimers are also synthesized by a stepwise route. On the other hand, the nickel-catalyzed dimerization of [5]cumulenes with bulky substituents produces other types of extended [4]radialenes and [5]radialenones depending on the bulkiness of the terminal alkyl substituents. Thus, tetrakis-t-butyl[5]cumulene and 1,4-bis(2,2,6,6-tetramethylcyclohexylidene)[3]cumulene react at the central double bond to give the corresponding [4]radialene and [5]radialenone, whereas 1,4-bis(2,2,5,5-tetramethylcyclopentylidene)[3]cumulene and its benzo-annelated derivative react at the second double bond in a head-to-tail manner to afford the corresponding extended [4]radialenes. Tetrakis-t-butyl[5]radialenone was converted into [5]radialene by using a methylation–dehydration procedure. The extended [4]- and [5]radialenes and [5]radialenones have been fully characterized by spectroscopic analyses, X-ray crystallography, and/or independent chemical synthesis. The properties of these novel exocyclic π-electron systems have been investigated in detail. The aryl-substituted [4]radialenes exhibit facile bond rotation with low energy barriers. The [5]radialene and [5]radialenone form the corresponding cations easily by the addition of an acidic proton. The selectivity of the nickel-catalyzed dimerization of [5]cumulenes is discussed on the basis of theoretical calculations.
  • Kentaro Okuma, Osami Sakai, Tetsuji Hayano, Kosei Shioji, Haruo Matsuy ...
    2005 Volume 78 Issue 12 Pages 2209-2213
    Published: 2005
    Released: December 09, 2005
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    The reaction of 6-methylene-1,3-dioxepanes derived from 3-hydroxyalkyltriphenylphosphonium salts and paraformaldehyde with trimethylsilyl trifluoromethanesulfonate in the presence of N,N-diisopropylethylamine yielded novel 4-formyltetrahydropyrans. 3-Methylenetetrahydropyrans were synthesized by the reaction of 4-hydroxyalkyltriphenylphosphonium iodides with DBU and paraformaldehyde. 2,3-Dihydro-3-methylenebenzofuran was also obtained by the reaction of 2-hydroxybenzyltriphenylphosphonium bromide with butyllithium, followed by the addition of paraformaldehyde.
  • Shinji Toyota, Michio Goichi, Masashi Kotani, Makoto Takezaki
    2005 Volume 78 Issue 12 Pages 2214-2227
    Published: 2005
    Released: December 09, 2005
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    The title π-conjugated oligomers consisting of anthracene and acetylene units were synthesized to construct a new type of three-dimensional organic architecture. An acyclic chain was extended by the sequence of the Sonogashira coupling and the desilylation from 1,8-diethynylanthracene derivatives and 1,8-diiodoanthracene to form a tetramer, which was then coupled intramolecularly to afford a cyclic tetramer as orange crystals. It is characteristic that a substituent free cyclic tetramer shows the hypochromic effect in the UV spectrum and the presence of an excimer-type emission in the fluorescence spectrum. X-ray analysis revealed that the cyclic tetramer took a diamond prism structure of nearly C2 symmetry, and the skeletal swing between the two enantiomeric forms via a square prism form was observable by dynamic NMR spectroscopy (barrier: ca. 38 kJ mol−1). The structural and spectral properties as well as some reactivities of the cyclic tetramer and related acyclic oligomers up to heptamer are reported.
  • Shinji Toyota, Akinori Takau, Yo Hitaka, Michinori Oki, Kan Wakamatsu
    2005 Volume 78 Issue 12 Pages 2228-2234
    Published: 2005
    Released: December 09, 2005
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    The title 9,9′-bitriptycyl compound, regarded as a stereochemical analogue of tartaric acid, possesses a total of five diastereomers, among which two rotamers belonging to the (R*,R*) form were isolated by chromatographic separation. Their relative stereochemistries were determined by X-ray analysis to be ap-(R*,R*) and sc*-(R*,R*). The enantiomers of these isomers were resolved by chiral HPLC and found to be optically and CD active. To predict the absolute stereochemistry, the CD spectra were calculated by the TDDFT method for the two rotamers as well as the chiral (R,S) form. The spectral pattern depends on the absolute arrangement of the two COOMe substituted benzeno groups, leading to the assignment of ap-(S,S), Psc-(R,R), and Msc-(R,S) for the (−)-forms. Since the achiral ap-(R,S) form was already known, we established the stereochemical relationship of all of the possible isomers of the tartaric acid-type molecule except for a pair of enantiomers of one missing isomer, the sc*-(S*,S*) form.
  • Motoki Asahara, Masaki Ohtsutsumi, Mina Tamura, Nagatoshi Nishiwaki, M ...
    2005 Volume 78 Issue 12 Pages 2235-2237
    Published: 2005
    Released: December 09, 2005
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    1-Methyl-3,6,8-trinitro-2-quinolone was found to be a suitable substrate for electrophilic arylation on benzene rings leading to (1,2-dihydro-4-quinolyl)phenols. The resultant products constitute a new family of 1-methyl-2-quinolones, which is often found in biologically active compounds as a partial structure.
  • Baojian Shen, Honglin Chen, Jintao Guo, Huifang Pan
    2005 Volume 78 Issue 12 Pages 2238-2244
    Published: 2005
    Released: December 09, 2005
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    A ZSM-5/Y composite zeolite was prepared from Y synthesis gel by using an in-situ two-step hydrothermal crystallization process. Optimized synthetic parameters made it practical to control the transformation of zeolite Y to P, or other undesired phases during ZSM-5/Y composite formation. It was found that the pH value range of the second phase (ZSM-5 in ZSM-5/Y composite) formation is much narrower than ordinary ZSM-5 synthesis, and a lower crystallization temperature was preferred in the second step. SEM showed that the morphology of the ZSM-5/Y composite was influenced by the different synthetic methods, such as seeds and templates. The NMR data indicated that the distribution of the Si(nAl) environments are different in ZSM-5/Y composite samples that made by different methods. The composite synthesized with seeds possessed a higher ratio of Si(0Al) to Si(1Al) than that of the composite synthesized with templates. Compared to a catalyst of a mechanical mixture of ZSM-5 and Y zeolite, the catalytic cracking performance of the ion-exchanged composite zeolite catalyst showed a better yield in gasoline formation when heavy oil was used as a feedstock in a MAT reactor, and the isomerization and aromatization abilities to the gasoline fraction were better than the physical mixture of the ZSM-5 and Y. This suggested that the composite structure of the zeolite may benefit the heavy oil transformation and related reaction steps during the course of the cracking process.
  • Shigeru Sugiyama, Masayoshi Fujisawa, Masahiko Yokoyama, Ken-ichiro So ...
    2005 Volume 78 Issue 12 Pages 2245-2250
    Published: 2005
    Released: December 09, 2005
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    In order to recover aqueous ammonium (NH4+) and phosphate (PO43−) from wastewater, these ions were immobilized with MgO and MgCl2 into an insoluble solid. Analysis by X-ray diffraction (XRD) showed that the insoluble solid was a single phase of ammonium magnesium phosphate (Mg(NH4)PO4·6H2O: MAP). Therefore, the present process has been commonly known as the MAP process. However, analysis by the solid-state 31P magic-angle spinning nuclear magnetic resonance (31P MAS NMR) of the insoluble solid revealed that the solid contained various phosphate compounds together with crystalline MAP. The results indicated that the solids obtained from the MAP process should be carefully identified, since they are considered to be utilized as a slow-acting fertilizer.
  • Tsutomu Shiragami, Keiko Nabeshima, Satoko Nakashima, Jin Matsumoto, S ...
    2005 Volume 78 Issue 12 Pages 2251-2258
    Published: 2005
    Released: December 09, 2005
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    Novel metalloporphyrin–clay composites were prepared from a synthetic clay (Sumecton SA: SSA) and cationic tetraphenylporphyrinatoantimony(V) bromide (SbTPP, 14) having various axial ligands. Both the crystal structure for SbTPP–SSA composites and the adsorption behaviors of SbTPP into SSA sheets are investigated regarding the relation to the structure of an axial ligand at SbTPP by measuring the X-ray diffraction (XRD), IR, UV–vis, and fluorescence spectroscopy. The XRD analysis revealed that powdered SbTPP–SSA composites could take a layered structure for 1, and an amorphous structure for 2, respectively. The IR spectrum of naked SSA showed a broad absorption band around 3000–3600 cm−1, which can probably be assigned as some adsorbed water molecules onto SSA. The intensity of the broad absorption band became weaker with an increase of the loading level (%LL), which was defined as a ratio of the concentration of the cationic sites of 14 to the concentration of anionic sites of SSA. The band completely disappeared at 100%LL in both 2–SSA and 4–SSA composites with the amorphous structure, whereas the band remained even at 100%LL in both 1–SSA and 3–SSA composites with the layered structure. Information about an aggregation state of 14 into SSA was obtained by measuring both the UV–vis absorption spectra of 14 in an aqueous colloidal clay solution and the fluorescence spectra of SbTPP–SSA composites in the solid state by using a confocal laser scanning fluorescence microscope. Each spectral data indicated that the ammonium cationic part on an axial ligand of 1 only led to effective non-aggregated adsorption onto SSA sheets, while 24 were located with the aggregated state on SSA sheets. These results also support that an axial ligand structure can control not only the formation of the crystal structure, but also the adsorption behaviors with aggregation or non-aggregation onto SSA sheets.
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