NIPPON KAGAKU KAISHI
Online ISSN : 2185-0925
Print ISSN : 0369-4577
Volume 1994, Issue 6
Displaying 1-15 of 15 articles from this issue
  • Hidemoto NOJIMA
    1994 Volume 1994 Issue 6 Pages 499-504
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    The low-temperature zone melting method was applied to the separation of iodine from benzene in order to investigate the similarity between multipass zone melting and fractional distillation. The experimental conditions were as follows: the initial concentration of the iodine was 0.5 mass%; zone travel rate was 0.91 cm/h; the number of zone passes were 1, 5, and 40 and the temperatures of the molten zone and the ambient air were 13°C and -10°C, respectively.
    The respective values of the effective distribution coefficients of iodine obtained from the results after 1 and 40 zone passes were 0.53 and 0.55. On the other hand, the equilibrium distribution coefficient determined from the freezing points of dilute solutions of iodine in benzene was found to be 0.25.
    After 40 zone passes the concentration of iodine near the top of the specimen was reduced to 1.11 × 10-4 mass%. The iodine distribution in the column after 40 zone passes was found to correspond to tha t after the fractional distillation of 14 stages, which was in agreement with the value estimated by the Pfann's theory. Moreover, the concept of the number of theoretical stages in the zone melting was represented by the xs(solid) -y1(liquid) diagram which resembles the xi (liquid) -yv( v apor) diagram in the fractional distillation. From these results the analogy between multipass zone melting and fractional distillation was explained in view of the phase equilibrium.
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  • Satoshi WATAUCHI, Akira UEDONO, Osamu YODA, Yusuke UJIHIRA
    1994 Volume 1994 Issue 6 Pages 505-511
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Defects in quartz glasses introduce absorption bands and as a result, the transmission efficiency of light decreases in long-path-length optical systems. Defects in amorphous SiO2 (a-SiO2) films, formed on MOS (metal/oxide/semiconductor) devices as gates, perturb its operation. The positron annihilation techniques, which has developed as a powerful method for detecting vacancy-type defects in materials, were applied to the study of the annealing behavior of the defects, introduced in the high purity synthetic quartz glass by the irradiation of 3-MeV electrons up to the 1 × 1018 e- /cm2 dosage. It was proved that the positron annihilation techniques were sufficiently sensitive to detect the defects in the electronirradiated silica glasses (Figs.3, 4, 5). Three types of open-space defects were detected by the positron lifetime measurements. These can be attributed to monovacancy or divacancy type defects, vacancy clusters, and open-volume defects (∼0.07 nm3). A high formation probability (∼90%) of positroniums (Ps) was found in unirradiated specimens. These Ps were considered to be formed in openvolume defects. The formation probability of Ps was drastically decreased by the electron irradiation. But the size of open-volume defects was kept unchanged by the irradiation. These facts suggest that vacancy-type defects such as monovacancies or divacancies were introduced by the electron irradiation and that positrons were trapped in these defects. By the isochronal annealing in nitrogen atmosphere, the lifetime component (τ2) and its relative intensity (I2), attributed to positrons trapped in monovacancy or divacancy type defects and annihilated there, changed remarkably (Figs.9, 10). τ2 was constant in the temperature range up to 300°C, getting slightly shorter between 300°C and 700°C, and constant above 700°C.I2 decreased gradually up to 300°C, constant between 300°C and 550°C, decreased above 550°C, and constant above 700°C. This revealed that the behavior of the defects, in which positrons were trapped, change by the elevation of the annealing temperature.
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  • Kiyoshi HORITA, Ken-ichi NAKATSU, Yasushi NISHIBORI, Satoshi KUBOTA
    1994 Volume 1994 Issue 6 Pages 512-517
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
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    The authors have investigated the surface properties which are electric conductivity, wettability, surface functional groups, and rate constant of H2O2 decomposition of surface modified acetylene black (AB) by low temperature oxygen plasma of dc glow discharge. This work also describes the relations between the surface properties and the electrochemical behavior in an aqueous KOH solution of the gas diffusion electrodes with oxygen plasma processed AB. The results are as follows; i) the conductivity of AB decreasing with processing time. ii) the AB surface changing from hydrophobic to hydrophilic. iii)making it possible to get AB high H2O2 decomposition ability by the plasma processing. These facts would be illustrated by the increase of oxygen functionalities such as aromatic -OH, >C=-O, -COOH etc. of AB surface. The polarization and discharge behaviors of oxygen electrode with AB have been much improved by the plasma processing. These can be regarded as forming the stable three phase zone owing to adapt wettability, high H2O2 decomposition ability, and developed fine pore of the AB electrode.
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  • Takashi HIBINO, Hiroyasu IWAHARA
    1994 Volume 1994 Issue 6 Pages 518-523
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    The hydrogen isotope separation was carried out by the steam electrolysis using the high temperaturetype protonic conductor as a solid electrolyte at 900°C. The total current and the electrolytic amount were reduced by replacing gaseous H2O with D2O. This was based on the increase in resistances of the bulk, anodic and cathodic reactions. The TPD (Temperature Programmed Desorption) and complex impedance methods suggested that the increase in bulk resistance was attributed to the decrease in mobility of the charge carrier. H2 was preferentially produced at the cathode by electrolyzing the mixture of gaseous H2O and D2O. In this case, the H/D atomic ratio for the gas evolved at the cathode was 1.61, and the separation factor was 1.44.
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  • Masayuki NOMURA, Giichi SAITO, Shin-ichi NAKATA, Yasuo MORIMURA
    1994 Volume 1994 Issue 6 Pages 524-530
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    From the point of view of the effective utilization as high additional value of natural sedimentary zeolites, characterization and catalytic reaction tests have been made. The samples in this study was natural clinoptilolite (FZ) produced in Futatsui, Akita Prefecture, and its specimens (HFZ) chemically treated with hydrochloric acid in various concentrations.
    Identification of clinoptilolite and in vestigation of crystallinities were made by X-ray diffraction. Structural analysis of microenvironments of zeolitic framework was made by high-resolution solid-state MASNMR. The amount of solid acid of zeolite surface was determined by micro-calorimetry of NH3 adsorption at 473 K.
    As the concen tration of hydrochloric acid is increased, the Si/Al atomic ratio of zeolites increased. The reaction rates on dehydration of 2-propanol over HFZ was proportional to the acid amount. On the skeletal isomerization reaction of cyclohexene into methylcyclopentenes over HFZ, as the concentration of hydrochloric acid increased, the yields of methylcyclopentane and aromatic hydrocarbons increased, while the yield of methylcyclopentenes decreased. The reaction over HZSM 5 gave only aromatic hydrocarbons.
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  • Shigeo MURAMATSU, Chiharu KATO, Kazumi HUJITA, Keizo MATSUDA
    1994 Volume 1994 Issue 6 Pages 531-537
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Strontium hydroxyapatite (Sr-HAp) was prepared by homogeneous precipitation method using the mixed solutions of SrCl2, NaH2PO4 and urea (Sr/P mole ratio = 1.67).Sr5 (OH) (PO4)3 (Sr-HAp), α-SrHPO4, β-SrHPO4, Sr3 (PO4)2, and SrCO3 were obtained at 97 (± 1) °C depending on the concentrations of Sr2+ and urea and heating time. α-SrHPO4 was obtained as the initial product in any synthesis condition. SrCO3 once formed remained in the products even after aging in the solution. It is prefered, therefore, that the synthesis of Sr-HAp is carried out with low concentration of urea to prevent the formation of SrCO3.
    The following two processes were revealed for the formation of Sr-HAp: (i) Sr-HAp is formed via Sri (PO4) 2 from α-SrHPO4 and (ii) Sr-HAp is formed via β-SrHPO4 from α-SrHPO4. These process es were governed by the pH change of the solution or the concentrations of Sr2+ and urea. Sr-HAp could be obtained as single phase by prolonged heating with low concentration of urea.
    It was unavoidable to incorporate impurities such as Cl- or CO32- into crystal of Sr-HAp by homogeneous precipitation method utilizing the hydrolysis of urea. The amounts of these impurities, however, could be minimized by the selection of the starting materials and/or the control of the concentrations of Sr2+ and urea.
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  • Takayuki FUJITA, Kunio KITAJIMA, Seiichi TARUTA, Nobuo TAKUSAGAWA
    1994 Volume 1994 Issue 6 Pages 538-544
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Layer charge of expandable Na-fluorine micas can be controlled by utilizing Al3+- f ixation into the hexagonal silicate holes. This also results in controlling the cation exchange capacity of host fluorine mica crystals. The layer charge controlled fluorine micas were reacted with the hydroxoaluminum solution containing a polynuclear complex, which was obtained by the reaction with zeolite. The hydroxoaluminum ion-mica composite thus formed have controlled intercalated Al-content, i. e. the controlled pillar density, corresponding to the variation of layer charge of host crystals. Effect of pillar density on micropore volume and thermal durability has been clarified for the pillared fluorine micas formed by heating at 200∼700°C for 1 h; Thermal durability of the pillared micas increased with pillar density. High specific surface areas (Langmuir) of 366 m2/g at 600°C of heating temperature and 226 m2/g even at 700°C were preserved in the high pillar density mica (1.58 mol Al/Si4O10). The micropore volume ofthe pillared micas depended on pillar density and heating temperature, indicating that appropriate pillar density and thermal treatment were essential for high micropore volume (ca.0.1 ml/g). The micropore size distribution obtained by the micropore analysis (MP method) also showed the dependence of pillar density.
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  • Shin-ichi TAKEKUMA, Yoshiharu MATSUBARA, Takao OBATA, Zhengbin ZHOU, Y ...
    1994 Volume 1994 Issue 6 Pages 545-550
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Electrochemical oxidation of methyl abietate (1) was investigated under some conditions in detail. As the results, two kinds of new compounds methyl 7a-acetoxy-13 (βand α)-hydroxy-8 (14) -abieten-18oate[ (2) and (3) ] identified by the spectroscopic (UV, MS, IR, NMR) data were obtained selectively up to 86% yield by the electrochemical oxidation of 1 (2 mmol) with an AcOH (30 ml) -H2O (5ml) -Et3N ( 2 g) -carbon electrodes system (constant current density 4 mA/cm2, electricity 4 F/mol, temperat ure 18°C) in an undivided cell. Furthermore, new compounds methyl 7α, 13 (βand α) -dihydroxy-8 (14) abieten-18-oate [(2') and (3') ] obtained by the alkali hydrolysis of acetoxyl group of 2 and 3 were also identified.
    A possible reaction pathway for the formation of 2 and 3 is described, too.
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  • Yoshiharu YONEYAMA, Osamu KITA, Syuichi YOSHIMOTO, Naoyuki NISHIMURA, ...
    1994 Volume 1994 Issue 6 Pages 551-559
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Yubari and Taiheiyo coals were converted to hexane soluble products in high yields by the repetitive butylation using zinc and butyl iodide under mild conditions (130 °C, under atmospheric pressure). The hexane soluble products were fractionated into seven fractions by column chromatography (CC), and the CC fractions were further separated by gel permeation chromatography (GPC) to investigate the chemical structure of the solvent-soluble products and the mechanism of the coal solubilization.
    The GPC fractions of both coals had high σal (degree of aliphatic chain substitution ) and low fa (aromaticity), because of the introduction of many butyl groups to coal aromatic moieties. The size of aromatic rings of the GPC fractions seemed to be small, 2-3 rings for Yubari coal; these small aromatic ring size may be caused by reductive butylation. The lower aliphatic chain length (L=2.1-2.9) of the GPC fractions, than expected from the introduction of many butyl groups (L = 4), also indicated the occurrence of reductive butylation. In addition, the yields (based on original coals) of the GPC fractions with average molecular weight below 800 were small 7.7 wt% for Yubari coal and 17.8 wt% for Taiheiyo coal, indicating that the linkage connecting aromatic moieties of coal was not broken so much.
    These characteristics of GPC fractions indicate that the high extractabilities of the bu tylated coals with solvents are mainly caused by the reductive butylation of aromatic moieties of the colas.
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  • Hiroyasu OGAWA
    1994 Volume 1994 Issue 6 Pages 560-564
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Oxidation conditions of precursor polyacrylonitrile (PAN) fibers govern not only the performance but also productivity of PAN-based carbon fibers. The effect of the incorporation of 2 wt% of comonomers, such as Sodium acrylate (SA), methyl acrylate (MA), acrylamide (AAm) and 2-hydroxyethyl acrylate (HEA) to PAN on the productivity of carbon fibers was investigated. DSC, ch emically-bound oxygen and formation of skin-core structure in oxidized fibers, and also carbon yield and tensile strength of carbonized fibers were measured. In order to get the high performance carbon fibers with high productivity, in other words, in short oxidation time, it was found that the precursor PAN fibers containing SA had to be oxidized in 2 steps; oxidation at 243°C, the maximum temperature not giving skin-core structure in the fiber, up to the chemically-bound oxygen content of about 5 % and then oxidation at 275°C up to the DSC exothermic calorie of about 10 cal/g or the total oxygen content of about 12%.
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  • Kazuyo ISAGAI, Kiyoharu ISAGAI, Katuyo NAKAZOE
    1994 Volume 1994 Issue 6 Pages 565-570
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Upto 1989, the pH of the rainwater at Saga city was kept around 5.0. However, in 1990, Mt. Fugen on Unzen erupted and in 1991, some extraordinary strong typhoons visited Saga prefecture. In this work, every event rainwater was collected for 24 months from June, 1990 to May, 1992. Electric conductivity, pH, concentrations of Na+, K+, Ca2+, Mg2+, SO42-, NO3-, NHt and Zn2+ were determined.
    The results showed that the rainwater at Saga city has a tendency of getting a higher acidity. The lowest pH value was 3.8. The reason is considered to be the effect of volcanic eruption and a small amount of rainfall.
    The concentration of NO3-, SO42- and Cl- in the rainwaters of these two years (1990-1992) were found to be higher than those of 1989. The rainwaters collected under typhoons contained high concentrations of SO42- and Cl- which were considered to be originated from sea salt. The difference between [nss-SO42- +NO3-] and [Ca2 +NH4+] in rainwaters on some typhoons is lower than that in us ual rainwater. Onthe other hand, that in rainwater affected by Mt. Unzen eruption is higher than other rainwaters.
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  • Ken YUKI, Tetsuo MURAKAMI, Hiroshi NARUKAWA, Takuii OKAYA
    1994 Volume 1994 Issue 6 Pages 571-576
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    Polymer cement mortar composed of poly (ethylene-co-vinyl acetate) (EVA) emulsion containing various kinds of stabilizer was investigated. Emulsion containing anionic emulsifier showed poor miscibility with cement. Addition of nonionic emulsifier to the emulsion improved the miscibility. Emulsion containing poly (vinyl alcohol) s (PVAs) as protective colloids and emulsion containing both hydroxyethylcellulose and nonionic emulsifier revealed good miscibilities. Apparent viscosity for polymer cement mortar composed of both kinds of emulsion or poly (styrene-co-butadiene) latex as a reference were measured at various shear rates. The polymer cement mortar composed of the emulsion containing PVA showed lower viscosities at low shear rates and higher viscosities at high shear rates compared with the other polymer cement mortars as well as a plain mortar. Casson plots of the data obtained above gave almost straight lines. Compressive, flexural and adhesive strength of the polymer cement mortars were measured. Unit weights of the wet mortars affeted the strengths to a great extent. Neither the kind of stabilizer nor the type of the polymer used showed difference in the strengths of the mortars.
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  • Noriyuki KAMEDA, Reiko IGARASHI
    1994 Volume 1994 Issue 6 Pages 577-579
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    The homogeneous hydrogenation of sorbic acid catalyzed by dihydrido (1, 3-diphenyltriazenido)bis (triphenylphosphine) rhodium ( DI ) (dihydridorhodium complex) in several solvents was studied under a 1 atm pressure of hydrogen at 50°C. The catalytic hydrogenation activity was found to decrease in the following order:
    Dimethyl su lfoxide (DMS0) > N, N-Dimethylformamide > Acetone > Benzene = Toluene > Tetrahydrofuran.
    The hydrogenation of sorbic acid with dihydridorhodium complex in the range of 30 to 60°C has been studied in DMSO. Main product obtained was trans-2-hexenoic acid at 30 and 40°C, and trans-2-hexenoic acid was further hydrogenated to hexanoic acid at 50 and 60°C. The apparent overall activation energy for the hydrogenation of sorbic acid with dihydridorhodium complex was estimated to be 51.0kJ mol-1.
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  • Akio YONEDA, Tadao HAKUSHI
    1994 Volume 1994 Issue 6 Pages 580-581
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    As polyligand souce, 2-vinyl-8-quinolinol (VQ) was prepared and polymerized at 60°C with 2, 2'azobisisobutyronitrile (AIBN). Vapor pressure osmometric analysis indicated that the molecular weight of the resultant polymer was small. VQ was copolymerized with styrene, methyl methacrylate, and vinyl acetate. The copolymers formed complexes with copper (II) perchlorate. Similar polymer complexes were obtained in the copolymerization between bis (2-vinyl-8-quinolinolato) copper (II) and styrene.
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  • Hiroshi KOMINAMI, Kazuki SAWAI, Mitsunori HITOMI, Ikuo ABE, Yoshiya KE ...
    1994 Volume 1994 Issue 6 Pages 582-584
    Published: June 10, 1994
    Released on J-STAGE: May 30, 2011
    JOURNAL FREE ACCESS
    The reactivity of nitrogen monoxide (NO) with several kinds of commercial charcoals for the fuel use was examined at 300-500°C by using a pulse reaction technique (Table 1). Among the charcoals studied mitsumata (Edgeworthia) charcoal that contained the highest level of potassium exhibited the highest activity for reduction of NO into N2. The NO-C reaction was remarkably enhanced by Cu-Cr metal loaded on charcoals. Conversion of NO significantly increased in the presence of propene because, in addition to the NO-C reaction, the NO-propene reaction was promoted by potassium present in the charcoal (Table 2).
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