Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 74 , Issue 4
Showing 1-23 articles out of 23 articles from the selected issue
  • Tomoyuki Yatsuhashi, Nobuaki Nakashima
    Type: scientific monograph
    2001 Volume 74 Issue 4 Pages 579-593
    Published: 2001
    Released: September 01, 2002
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    The hot molecule (S0**) is in a highly vibrationally excited state formed by rapid internal conversion from initially prepared electronic excited states. The importance and predominance of the S0** mechanism in VUV gas phase photochemistry has been demonstrated. In this account, the fundamental physicochemical properties of S0** are discussed in order to understand the characteristic features of S0** reactions, and VUV laser chemistry is reviewed from the following two points of view: 1) The generalization and classification of VUV chemistry for a variety of molecules, including the hot molecule mechanism and other competitive mechanisms; 2) A new strategy of multiphoton chemistry that employs hot molecule as an intermediate. Internal conversion is a dominant deactivation process for many molecules in the VUV region. Aromatic hydrocarbons and olefins are the representative examples of S0** reactions. However, fluorescence and intersystem crossing are major deactivation processes in some cases such as large condensed aromatic hydrocarbons. The reactions of chlorinated compounds and phenols are explained by other reaction mechanisms such as direct dissociation and predissociation. Carbonyl compounds and some amines are classified into the intermediate cases. Due to the large molar extinction coefficient and relatively long lifetime of S0**, the multiphoton absorption process can be induced by a single nanosecond laser pulse. As a result of fast internal conversion and intramolecular energy redistribution, the second photon and further photons will not be absorbed by the molecule in the electronic excited state but by that in the S0**, and the photon energy of the multiphoton is accumulated as vibrational energy. Therefore, ionization is minor process in the case of the multiphoton reaction of S0**. The neutral radical formation is predominant in the dissociation reaction, and the rate constant increases because the internal energy is multiplied by the multiphoton absorption process. The applications of these findings lie in the following: 1) Large molecules of which the single-photon hot molecule reaction rate is small; 2) Molecules which have been deemed to be photoinert.
  • Masahide Terazima
    Type: scientific monograph
    2001 Volume 74 Issue 4 Pages 595-611
    Published: 2001
    Released: September 01, 2002
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    Energy transfer processes from a photoexcited ion and molecules to solvents were studied from the rate of the temperature rise of the solvent using several newly developed techniques: temperature grating, temperature lens, acoustic peak delay, and molecular heater–molecular thermometer methods. These energy transfer processes are closely related to the well-studied vibrational relaxation (cooling) process but the overall energy transfer process can be monitored by detecting the time course of the matrix heating. In aqueous solution, most of the energy of a photoexcited ion transfers to the thermal mode within 2–3 ps after the populational relaxation to a lower electronic state. In organic solvents, the process is described by roughly two kinetics: fast ( ≤ 1 ps) and slow (20–30 ps). This two-phase kinetics was explained by a simple thermalization model; the initial fast process represents the energy transfer to the doorway molecules in the first solvent shell molecules and the slower one represents the thermal diffusion process from the hot solvent molecules to the bulk solvent molecules. A new molecular heater-molecular thermometer integrated system is also described.
  • Shiro Kobayashi, Hiroshi Uyama, Masashi Ohmae
    Type: scientific monograph
    2001 Volume 74 Issue 4 Pages 613-635
    Published: 2001
    Released: September 01, 2002
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    Our recent advances in enzymatic polymerization, defined as chemical polymer syntheses in vitro (in test tubes) via non-biosynthetic pathways catalyzed by an isolated enzyme, have been mainly reviewed. The major target macromolecules formed via the enzymatic polymerizations described in this article are polysaccharides, polyesters, and polyaromatics. For synthesis of polysaccharides and polyesters, hydrolases are used as catalysts; hydrolases catalyzing a bond-cleavage reaction by water induce the reverse reaction of hydrolysis, leading to polymer production by a bond-forming reaction in vitro. Specific enzyme catalysis provides a novel synthetic route with precise structure control not only for natural biopolymers such as cellulose, xylan, and chitin, but also for unnatural polysaccharides and polyesters, many of which are difficult to be synthesized by conventional methodologies. Oxidoreductases act as catalysts for oxidative polymerization of phenol, aniline, and their derivatives. A new class of phenolic polymers are synthesized without use of toxic formaldehyde under mild reaction conditions. Enzyme-model complexes also catalyze polymerizations for the synthesis of new high-performance polymeric materials.
  • Hiroto Yoshida, Eiji Shirakawa, Yoshiaki Nakao, Yuki Honda, Tamejiro H ...
    Type: technical report
    2001 Volume 74 Issue 4 Pages 637-647
    Published: 2001
    Released: September 01, 2002
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    Double insertion of alkynes into the C–Sn bond of an alkynyl-, alkenyl-, allyl- or arylstannane proceeded in the presence of a palladium–diimine complex to afford highly conjugated alkenylstannanes with exclusive syn selectivity. Perfect regioselectivities were observed in the dimerization–carbostannylation of ethyl propiolate with a palladium–1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene complex, which allowed regio- and stereoselective synthesis of stannyl-substituted muconic acid derivatives. The π-conjugation of the dimerization–carbostannylation products was further extended through a cross-coupling or homocoupling reaction. A palladacyclopentadiene is proposed as an intermediate species.
  • Shozi Mishima, Tsuyoshi Nakajima, Nobuaki Tanaka
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 649-655
    Published: 2001
    Released: September 01, 2002
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    For 1 : 1 hydrogen-bond complexation in CCl4, novel local structural parameters, η° and ω°, representing the nature of the functional group and the residual moiety (supporting group) of acids and bases have been evaluated for two acids and 26 bases. An evaluation of the η° and ω° was carried out by using convergent linear relationships observed among the log K values of the bases against each couple of reference acids. The values of log K experimentally obtained were reproduced from the η°and ω° values within ±0.21 in the log K unit, excluding three exceptions. Family-independent linear relationships were observed between ω°b and the solute hydrogen bond basicity (β2H), and between ω°a and the solute hydrogen bond acidity (α2H) of the bases and acids. Linear relationships could be applied to estimate the ω°a and ω°b values from α2H and β2H values existing in the literature.
  • Toshiyuki Ito, Masao Naka, Atsushi Miura, Tomomi Ujiie, Hiroshi Nakamu ...
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 657-665
    Published: 2001
    Released: September 01, 2002
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    The effects of magnetic fields on the lifetimes of chain-linked triplet biradicals (3BRs), generated by photoinduced electron transfer from zinc(II) tetraphenylporphyrin (ZnP) to appended viologen (V2+), were investigated in homogeneous solutions of acetonitrile-water and reversed micellar solutions of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) by means of laser flash photolysis. It was found that the decay rate constants (kobs) of the 3BRs increased significantly in the absence of magnetic fields as the number of carbon atoms (n) in the spacer chain between the ZnP and V2+ moieties increased, and then reached a constant value above n = 8. When the magnetic field was increased, the kobs values decreased. A sharp decrease in a low magnetic field was observed, followed by a gradual decrease as the magnetic field was increased, eventually reaching an asymptotic value under the high magnetic field (B > 100 mT) for the compounds with the longer spacer chains. In AOT/2,2,4-trimethylpentane/water reversed micellar solutions, the kobs values were smaller than those in MeCN–H2O homogeneous solutions; this trend became increasingly prominent the longer the spacer chain length. Therefore, the kobs values showed the opposite spacer chain length dependence in comparison with those in homogeneous solutions at B = 470 mT. These results were interpreted in terms of the variation of triplet-singlet energy separation with the interradical distance, Zeeman splitting of the triplet sublevels, electron–nuclear hyperfine coupling, and spin relaxation mechanisms.
  • Yoshikiyo Moroi, Hiroaki Yano, Osamu Shibata, Tadashi Yonemitsu
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 667-672
    Published: 2001
    Released: September 01, 2002
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    Acidity constants (Ka) of perfluoroalkanoic acids were determined by pH titration and by electric conductivity for shorter alkanoic acids (C1 to C5) with 1 to 5 carbon atoms in the alkyl chain. The acidity constants obtained by the two methods are in good agreement. They increase from C1 (ethanoic) to C3 (butanoic acid) and then decrease from C3 to C5 (hexanoic acid) with increasing alkyl chain length. An abrupt decrease in the Ka value for the C5 acid occurred; the attempt to explain this in terms of viscosity of the solutions did not succeeded. The decrease in the Ka values with increasing alkyl chain length was substantiated by the values for C9 (decanoic) to C11 (dodecanoic) acids, which were determined from the solubility change with the solution pH. For the intermediate alkanoic acids (C6 to C8), the Ka values could not be determined precisely by these methods due to the extreme difficulty in separating the colloidal acid particles from the aqueous phase, because the particles have an emulsifying action of their own.
  • Teiichiro Ogawa, Daisuke Murata, Hirofumi Soga, Keiji Nakashima
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 673-676
    Published: 2001
    Released: September 01, 2002
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    Pyrene has two photoconductivity thresholds in the wavelength region of 360–435 nm (two-photon energy: 5.70–6.89 eV) in nonpolar hydrocarbon and tetramethylsilane. The first one is located at 6.04–6.44 eV and the second one at 5.18–6.11 eV. The former was assigned to direct ionization and the latter to an ion-pair formation process. Direct ionization is the major process.
  • Ya-Chien Huang, Po-Hua Su, Chen-Sheng Yeh
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 677-688
    Published: 2001
    Released: September 01, 2002
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    The gas-phase reactions of group-11 ions (Cu+,Ag+, and Au+) with 2-propanol were investigated using laser vaporization combined with supersonic beam expansion in a time-of-flight mass spectrometer. A number of reaction pathways, including assoication, dehydrogenation, and dehydration, were observed. Among these metal ions, Au+ is highly reactive toward 2-propanol. The experimental results are parallel to studies by Wilkins et al. using an FT-ICR mass spectrometer (J. Am. Chem. Soc., 107, 7316 (1985)). The geometries and binding energies of all complexes M+–L, where M+ = Cu+, Ag+ , and Au+, L = 2-propanol, acetone, propene, and H2O, were estimated using Møller–Plesset perturbation (MP2) and density functional theory (BLYP). The bond strengths of the complex ions involving gold revealed the strongest bonding, due to a relativistic effect. The energetic relationship between the reactants and the products facilitated an interpretation of the observed exit channels. Because of the supersonic beam source employed, larger clusters containing metal ions were generated as well. Because the cluster sizes with solvent molecules were ≥ 2, the reactivities were apparently limited to Cu+ and Ag+ clusters, while the reactive nature changed in Au+ along with the formation of acetone, lacking in the bare Au+ reactions. For larger clusters, calculations on Ag+–(2-propanol)2 and Ag+–(2-propanol)(acetone) complexes using BLYP were performed to obtain their energetics.
  • Takehito Senga, Akihiro Yabushita, Yoshihiko Inoue, Masahiro Kawasaki, ...
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 689-697
    Published: 2001
    Released: September 01, 2002
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    The photodissociation dynamics of N2O4 multilayers adsorbed on a polycrystalline Au substrate at 80–140 K was investigated. The Au substrate was mainly composed of domains with (111) structure. Time-of-flight spectra of the photofragment NO and O as well as infrared reflection absorption spectra for the surface adsorbed species on the Au substrate were measured. Typically, four to five monolayers of N2O4 adsorb on the Au substrate at 85 K were irradiated by the pulsed output of an excimer laser at λ = 193 and 351 nm. Photodissociation of the adlayers at 193 nm takes place by direct photoabsorption of N2O4. Since the top layers of N2O4 absorbed the UV light, superthermal NO and O photofragments are produced. Translationally and internally relaxed fragments are also produced from the photodissociation of the inner layers. At 351 nm, the bulk photoexcitation results in formation of slow NO photofragments. By comparing the effect of dissociation wavelengths, substrate temperatures and dose rates, it is shown that the photodissociation dynamics is governed by both the photoexcitation process and the adsorption state of N2O4 on the Au substrate.
  • Yulin Lam, Ngai Ling Ma, Eping Liang
    Type: Introduction
    Subject area: TP
    2001 Volume 74 Issue 4 Pages 699-700
    Published: 2001
    Released: September 01, 2002
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    The reaction of dicyclopropyl ketone with hydrazine sulfate and sodium cyanide afforded 1,1′-bis(1-amino-4,4-dicyclopropyl-2,3-diaza-1,3-butadienyl). The compound exists in the trans conformation in the solid-state and has a trans population of 91.2% in solution. Experimental data are compared with values estimated by ab initio calculations.
  • Dusan J. Radanovic, Tomoharu Ama, Hiroshi Kawaguchi, Nenad S. Draskovi ...
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 4 Pages 701-706
    Published: 2001
    Released: September 01, 2002
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    The hexadentate complex Mg[Ni(1,3-pdta)]•H2O (1,3-pdta = 1,3-propanediaminetetraacetate ion) was prepared and its structure established by X-ray crystallography. The complex salt crystallizes in the space group Pnna (# 52) of the orthorhombic crystal system with a = 13.251(2), b = 11.645(2), c = 13.818(3) Å and Z = 4. The Ni(II) ion is surrounded octahedrally by two nitrogen and four oxygen atoms of the ligand. The Mg cation is bonded octahedrally to six water molecules. Both complex ions utilize a two-fold symmetry axis that is present in the crystal. The conformations of the chelate rings were found to be envelope or twist for the glycinates and skew-boat for the six-membered diamine ring. A comparison of structures of hexadentate [M(1,3-pdta)]n complexes shows an expected variation in their octahedral distortion depending on the central metal ion M. Some spectral characteristics of the complex studied have also been reported.
  • Makoto Takemura, Kazuhiro Yamato, Matsumi Doe, Masaaki Watanabe, Hiroy ...
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 4 Pages 707-715
    Published: 2001
    Released: September 01, 2002
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    Three N,N′-ethylenebis(L-amino acid) ligands have been obtained simultaneously with three α,α′-(1,4-piperazinediyl)bis[(S)-alkanoic acid] and four N,N′-ethylenedipeptide products, by reacting a mixture of L-histidine methyl ester and L-aspartic acid dimethyl ester with glyoxal in the presence of sodium cyanotrihydroborate in methanol. Europium(III) complexes with N,N′-ethylenebis(L-amino acid) ligands were useful as chiral NMR shift reagents for some unprotected natural α-amino acids as substrates in neutral aqueous solution, as characterized by large enantiomeric shift differences and unbroadened signal shapes on high-resolution NMR spectroscopy. In addition, the acid-dissociation constants of six bis(amino acid) ligands and the stability constant of the europium(III) complex with N,N′-ethylenedi(L-histidine) were obtained by potentiometric titration.
  • Isao Ando, Kikujiro Ujimoto, Hirondo Kurihara
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 4 Pages 717-721
    Published: 2001
    Released: September 01, 2002
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    The inclusion of pentaammineruthenium(II) and pentacyanoferrate(II) complexes with nitrogen heterocycles into cyclodextrins was investigated by UV-visible spectrophotometry, 1H-NMR spectroscopy, and cyclic voltammetry. The stability constants of the inclusion adducts of the metal complexes into cyclodextrins were determined by capillary electrophoresis. The complexes form adducts with cyclodextrins by the inclusion of an aromatic ligand moiety of the complex into the cavity of cyclodextrins. The adduct formation caused a modification of the redox behavior of the complex. The stability of the cyclodextrin adduct was influenced by the included aromatic ligand of the complex and the cavity size of cyclodextrin, especially the positive charge on the aromatic ligand.
  • Tomohiro Kyotani, Satoshi Koshimizu
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 4 Pages 723-729
    Published: 2001
    Released: September 01, 2002
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    A method of scanning electron microscopy-energy dispersive X-ray microanalysis (SEM-EDX) has been investigated for the identification of individual Si-rich particles derived from Kosa aerosol. The elemental composition of individual Si-rich particles (α-quartz) having SiO2 content over 80% was determined by SEM-EDX using a standardless φ(ρz) correction program, and the results were normalized to 100% on the basis of oxide composition. The distribution of (Na2O+K2O)/SiO2(%) in individual Si-rich particles from real airborne particulate matters showed a sharp and clear seasonal variation. It was found that the distribution was closer to those in the China loess and desert sand in spring time compared to those of the non-Kosa aerosol, the distribution could be successfully used as an effective indicator. The distribution of (MgO+CaO)/SiO2(%) was also used for discrimination from Si-rich particles in some Japanese volcanic rocks such as Andesites. Individual Si-rich particles derived from Kosa aerosol were clearly discriminated from those derived from the Japanese igneous rocks by the proposed method. These results suggest that the alkali elemental composition of individual Si-rich particles is a useful indicator to identify the Kosa particles and to investigate transportation of the Kosa aerosol.
  • Katsuo Asakura, Tsuneo Imamoto
    Type: Introduction
    Subject area: AI
    2001 Volume 74 Issue 4 Pages 731-732
    Published: 2001
    Released: September 01, 2002
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    The crystal structures of new samarium(III) bromide–HMPA complexes were accurately determined by single crystal X-ray analysis. The Lewis acidity of samarium(III) cation is discussed based on the crystal structures of several samarium(III)–HMPA complexes.
  • Hitoshi Tamiaki, Tomoyuki Obata, Yasuo Azefu, Kazunori Toma
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 4 Pages 733-738
    Published: 2001
    Released: September 01, 2002
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    3,4,5-Tris(octadecyloxy)benzyl alcohol, HO–Bzl(OC18)3, was prepared from gallic acid and stearyl bromide. Using conventional step-wise elongation, N,C-protected peptides, Fmoc–AAn–...–AA1–OBzl(OC18)3, were synthesized. The substituted benzyl esters were selectively cleaved by a treatment with 4 M hydrogen chloride in ethyl acetate to give Fmoc–AAn–...–AA1–OH and HO–Bzl(OC18)3. Thus, the substituted benzyl group is effective for the protection of C-terminal carboxyl groups in liquid-phase peptide synthesis. Because the substituted benzyl group has a moderately high molecular weight, Fmoc–AAn–...–AA1–OBzl(OC18)3 can be easily purified by size-exclusion chromatography; all protected peptides are eluted in the void fraction of a Sephadex LH-20 gel-filtration column. The combination of the carboxyl-protecting group Bzl(OC18)3 with simple purification by the gel-filtration gives a novel route for constructing combinatorial peptide libraries in the solution phase.
  • Masato Ikeda, Masayuki Takeuchi, Seiji Shinkai, Fumito Tani, Yoshinori ...
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 4 Pages 739-746
    Published: 2001
    Released: September 01, 2002
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    Tetraaryl-substituted cerium(IV) double-decker porphyrin (2D), tetraaryl-substituted lanthanum(III) double-decker porphyrin (3D), and diaryl-substituted lanthanum(III) triple-decker porphyrins (4T•Me and 4T•MeO) were newly synthesized and their porphyrin ring rotation rates were systematically estimated by means of a VT NMR spectroscopic method. In 2D the coalescence temperature (Tc) for the porphyrin ring rotation was higher than 110 °C, whereas in 3D it appeared at ca. 0 °C. In diaryl-substituted cerium(IV) double-decker porphyrin (5D) it appeared at 13 °C whereas in 4T•Me and 4T•MeO they were lower than −80 °C. These results consistently support the view that the porphyrin ring rotation rates in lanthanum(III)-based porphyrins are much faster than those in cerium(IV)-based porphyrins. The difference is reasonably explained by the difference in the ion size between these two metal ions. Since these sandwich-type porphyrins can act as novel scaffolds for designing positive allosteric recognition systems, La(III) complexes which feature the faster porphyrin ring rotation should be useful to develop more efficient positive allosteric systems.
  • Tomoaki Nakamura, Hideki Yorimitsu, Hiroshi Shinokubo, Koichiro Oshima
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 4 Pages 747-752
    Published: 2001
    Released: September 01, 2002
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    Tri-2-furylgermane proved to be an effective reagent for the radical reduction of organic halides. Treatment of 1-bromododecane with tri-2-furylgermane in THF at 25 °C in the presence of a catalytic amount of triethylborane afforded dodecane almost quantitatively. Radical cyclization of 2-iodoethanal allyl acetal afforded five-membered products under the same reaction conditions. These reactions proceeded with NaBH4 in the presence of a catalytic amount of germanium hydride. The reaction took place in water as well as in THF to give the corresponding reduced compounds in good yields.
  • Kiitiro Utimoto, Yasuyuki Otake, Hideaki Yoshino, Eiko Kuwahara, Koich ...
    Type: Introduction
    Subject area: OB
    2001 Volume 74 Issue 4 Pages 753-754
    Published: 2001
    Released: September 01, 2002
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    Protodesilylation of the aryl moiety in (p-methoxyphenyl)dimethylsilyl and (2,6-dimethoxyphenyl)dimethylsilyl groups proceeds much faster than that in a phenyldimethylsilyl group under acidic conditions; these aryl groups can be substituted with an F atom to give organosilyl fluoride even in the presence of an acid-sensitive group such as an alkenyl group.
  • Naoki Kise, Nasuo Ueda
    Type: Introduction
    Subject area: OB
    2001 Volume 74 Issue 4 Pages 755-756
    Published: 2001
    Released: September 01, 2002
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    The direct electroreduction of aromatic acyl bromides gave aromatic 1,2-diketones. The best result was obtained using a Pb cathode in acetonitrile containing Bu4NClO4 as a supporting electrolyte. Aromatic acyl bromides substituted by an electron-donating group afforded 1,2-diketones in moderate-to-good yields, whereas acylated endiols were formed exclusively from aromatic acyl bromides substituted by an electron-withdrawing group.
  • Tadahiro Kurosaka, Masatoshi Sugioka, Hiromi Matsuhashi
    Type: Others
    Subject area: AM
    2001 Volume 74 Issue 4 Pages 757-763
    Published: 2001
    Released: September 01, 2002
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    The effects of the proton content of ZSM-5 and the amount of Pt on the hydrodesulfurization (HDS) activity of Pt/ZSM-5 were studied. The extent of proton exchange was shown to affect the reaction selectivity, the formation of aromatics, the cracking of hydrocarbons, and the dispersion of Pt. The HDS activity depended on the surface area of loaded Pt. A catalyst consisting of 5 wt% Pt supported on a 50% cation exchanged ZSM-5 gave a higher HDS activity than other tested catalysts and a small amount of cracking products.
  • Tisato Kajiyama, Ryota Tominaga, Ken Kojio, Keiji Tanaka
    Type: Others
    Subject area: AM
    2001 Volume 74 Issue 4 Pages 765-771
    Published: 2001
    Released: September 01, 2002
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    Crystal transition behavior of lignoceric acid (LA) monolayer was structurally investigated by electron diffraction (ED) in conjunction with scanning force microscopy (SFM). LA molecules form two-dimensional hexagonal crystallites right after one spreads a solution at the air/water interface. The hexagonal-rectangular transition of the LA monolayer was attained by two different experimental procedures: monolayer compression under an isothermal condition and monolayer cooling under an isobaric condition. In the compression process, the hexagonal and rectangular phases coexisted in the monolayer at the surface pressure, π, of 10 mN m−1, which was slightly lower than the plateau pressure, and the subphase temperature of 293 K. When the π exceeded the plateau pressure, the hexagonal phase in the LA monolayer was entirely transformed to the rectangular one. High-resolution SFM showed that the crystal transition from the hexagonal to rectangular phase proceeded via a quasi-disordered phase upon compression. A similar hexagonal-rectangular transition was also observed during the monolayer cooling process at the π of 15 mN m−1. Based on SFM observation, we claimed that the molecular ordering or packing state in the rectangular lattice induced by cooling was better than that by the monolayer compression. Finally, the crystal transition mechanisms for these two procedures were proposed.
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