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Tetsuo KUSUMOTO, Tamejiro HIYAMA, Sadao TAKEHARA
1992 Volume 1992 Issue 12 Pages
1401-1411
Published: December 10, 1992
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New chiral dopants having a chiral ring structure were designed and synthesized. The materials investigated here are three-membered ring compounds such as cyanocyclopropanes, fluorocyclopropanes, (trifluoromethyl)cyclopropanes, and difluorocyclopropanes, five-membered ring compounds such as γ-lactones, tetrahydrofurans, and 2-oxazolidinones, six-membered ring compounds such as 1, 3-dioxanes and 1, 3-dioxan-2-ones, and 1, 3-diols which form a sixmembered ring through intramolecular hydrogen bonding. The ferroelectric liquid crystal mixtures doped with one of these compounds exhibited high spontaneous polarization (Ps).
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Norio IWASHITA, Michio INAGAKI
1992 Volume 1992 Issue 12 Pages
1412-1422
Published: December 10, 1992
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Electric potential of graphite during intercalation of sulfuric acid by chemical oxidation was found to increase in stepwise to positive direction, and reflect the change in stage structure of graphite intercalation compounds with sulfuric acid (H
2SO
4-GICs). It was shown that the intercalation behavior of sulfuric acid into graphite by the chemical oxidation method could be followed by in-situ measurement of electric potential.
From the potential change, the intercalation p rocess of sulfuric acid by the chemical oxidation method was found to be fundamentally the same as that by electrochemical one. The intercalation reaction is divided into two processes; one is charging process of host carbon layers corresponding to the potential increase and another is transformation process of stage structure in GICs showing the plateau on the potential curve.
The potential increase of graphite in sulfuric acid soluti on by the chemical oxidation process was limited by the equilibrium potential of redox reaction of oxidant used, which is determined on the activities of each chemical species in the solution. Effects of dilution of sulfuric acid on the formation of H
2SO
4-GICs could be explained in term of the balance between the upper limit of saturated potential in the chemical oxidation and the onset potential for each stage structure.
The intercalation behavior of sulfuric acid by the chemical oxidation process depended strongly on the structure and the texture of host carbon materials. The effect of host carbon materials on the potential change during the chemical intercalation could be explained on the basis of competition of reaction rates between the charging of carbon layers and the stage transformationlin the gallery.
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Tsuyoshi HIRATA, Koichi MIYAGAWA, Yasumasa IHAYA, Hisao MURAI
1992 Volume 1992 Issue 12 Pages
1423-1428
Published: December 10, 1992
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The reactions between photoexcited benzophenone and several aromatic amines were studied by a time-resolved ESR technique in different kind of micellar solutions (SDS, CTAB and Brij 35) at room temperature. The systems of benzophenone(BP)/N, N-dimethylaniline and BP/N, N-diethylaniline showed the formation of an emissively spin-polarized benzophenone anion radical in all micellar solutions. The systems including N-methyl- and N-ethylanilines showed mainly the benzophenone ketyl radical with emissive spin-polarization in SDS and CTAB micellar solutions, and the benzophenone anion radical in Brij 35. The systems including aniline yielded an emissively spin-polarized aniline N-centered radical in all the micelles. All the emissive spin-polarization observed is explained by the triplet mechanism of CIDEP. These experimental results lead to the conclusion that such micellar environments and/or interfaces promote a function of charge separation and prohibit a back charge transfer of a transient charge transfer complex or a radical-ion pair formed immediately after photolysis, when amines have low ionization potentials.
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Isao MOCHIDA, Seiki KISAMORI, Sizuo KAWANO, Hiroshi FUJITSU
1992 Volume 1992 Issue 12 Pages
1429-1434
Published: December 10, 1992
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SO, removal activity of a commercially PAN-ACF, FE-300 was examined at 100 °C in its repeated use by regenerating it at a temperature range of 400-1000 °C, using model flue gas containing 1000 ppm SO, . The particular ACF showed an excellent removal activity after the heat treatment at 800 °C (FE-300-800) providing a breakthrough time of 5.1 h. However its activity was so much reduced in the second successive runs to be 50% of the first run, when its ACF was regenerated before the successive are at 500 °C, where adsorbed SO
2 was completely recovered.
High temp erature of 800 °C regenerated more the activity, although the breakthrough time was still 4.5 h in the second run, and decreased steadily in the successive runs. Such regeneration provoked a large carbon loss by evolving CO, and CO after the recovery of SO
2.
The activity was almost completely regenerated when the ACF was treated with NH 3 at 500 °C after the complete recovery of SO
2. NO was found reduced with NH
3 at 500 °C over the ACF after the recovery of SO
2, exhibiting a conversion of 60% recovery of SO
2 adsorption ability. Reduction with NH
3 for the recovery of SO, adsorption led to no carbon loss at the regeneration. The role of oxygen functional groups introduced by oxidative adsorption and desorption of SO
2 are discussed for the oxidative adsorption of SO2 in the successive runs.
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Tadashi NAKAMURA, Kiyonori SHINODA, Kensei YASUDA
1992 Volume 1992 Issue 12 Pages
1435-1439
Published: December 10, 1992
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Since thermal conversion of carbon tetrachloride into tetrachloroethylene is an endothermic reaction, it is necessary that the reaction is performed at high temperatures such as 750 °C. On the other hand, the reaction of carbon tetrachloride with 1, 2-dichloroethane in the presenc e of oxygen is an exothermic reaction and possibly proceeds at lower temperatures.
We examined the reaction of EDC or 1, 2-dichloropropane with CTC in the presence of oxygen with an oxychlorination catalyst and obtained the following results.
( 1 ) The reaction of EDC with CTC to PCE proceeded at about 400 °C over supported CuC12-KC1 catalyst.
( 2 ) DCP was also converted into PCE under the similar reaction conditions.
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Toshinko Hoshi, Yasunori YAMADA, Asami FUKUMORI, Jun OKUBO, Michio KOB ...
1992 Volume 1992 Issue 12 Pages
1440-1445
Published: December 10, 1992
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4, 4'-Dimethylbenzil shows four n→π* transitions at 381.0, 358.5, 338.0 and 330 nm in EPA (ether: isopentane: ethanol=5: 5: 2) at 101 K. From configuration analysis, it is found that 381.0 and 358.5 nm bands can be assigned to the n→π* transitions localized separately on the two benzoyl moieties, and the 338.0 and 330 nm bands to the n-, 27-* transitions, having intramolecular CT characters, from the n orbital of the oxygen atom to the 7r* orbital belonging to the different benzoyl moiety. The 232.5 nm band, observed in the PE(polyethylene)film at 101 K, has mixed natures of the n→π* transition with intramolecular CT character and the nearby intense π→π* one. The polarized absorption spectrum, measured in the stretched PE film at 101K, shows that the intense, π→π*band, appearing in the wavelength region 250-320 nm, is composed of the three electronic bands at 293, 278.5 and 272 nm, whic h can be assigned to the S
5←S
0, S
7←S
0 and S
8←S
0 transitions, respectively. Splitting features of the above mentioned n→π* transitions indicate that the two n orbitals interact significantly. The n orbital also interacts with the 7r orbital belonging to the different benzoyl moiety.
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Jun YATABE, Toshio SUGIZAKI, Osamu MORIYA, Toshifumi KAGEYAMA
1992 Volume 1992 Issue 12 Pages
1446-1449
Published: December 10, 1992
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Epoxidation of olefins with sodium bromite was st udied in the alkaline aqueous solution. The epoxidation proceeded effectively at room temperature in the presence of small amount of copper ion. No epoxidation occurred without copper ion. It is considered that copper ion is reacted with sodium bromite to give unstable copper(II)bromite. Reaction of epoxidation is proposed as follows.
_??_
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Takayuki SUYAMA, Yoshinori SHIMAMURA, Yuichiro MAKISHMA
1992 Volume 1992 Issue 12 Pages
1450-1454
Published: December 10, 1992
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4-Alkoxy-6-amino-2 H-1, 3, 5-thiadiazine-2-thiones 5 J were prepared by the reaction of N'-cyano-O-alkylisourea [4] with carbon disulfide in the presence of potas sium hydroxide, f ollowed by acidification. Thiadiazine [5 a] (R=Et) rearranged into 6-ethoxy-1, 3, 5-triazine-2, 4(1 H, 3 H)-dithione [9] in ethanolic sodium hydroxide, whereas yielded dimethyl N-a(cyanoimino)ethoxymethyljimidodithiocarbonate [3 ] by the reacti on of methyl iodide in the presence of potassium hydroxide. Heating of 5 in water resulted in the hydrolysis at 4-position of thiadiazine ring and N'-(alkoxycarbonyl)thioureas [10] were obtained.
6-Amino-4-(substituted amino)-1, 3, 5-2 H-thiadiazine-2-thione 1 could b e obtained by the reaction of [5 a] with amines, and the reactivity of [1] was also investigated.
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Takeo KONAKAHARA, Shin KUBOTA, Kazuya SANO, Takashi MURAYAMA
1992 Volume 1992 Issue 12 Pages
1455-1462
Published: December 10, 1992
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As an extension of our synthetic investigation on heterocycles using silicon reagents, preparation of perfluoroalkyl-1 H-benzo[ c ]quinolizin-1-onesw as studied. An addition-cyclization reaction of perfluoro(2-methyl-2-pentene) [ 2 ] with a 2-quinolylmethyl carbanion generated from 2-(trimethylsilylmethyl)quinoline [3 a] in the presence of a catalytic amount of tetrabutylammonium fluoride (TBAF) afforded 3-pentafluoroethyl-2-trifluoromethyl-1 Hbenzo[c ]quinolizin-1-one [6 a] in 36% yield, accompanied with the corresponding adduct [4 a] and E/Z alkenes [5 a] (1, 29 and 11% yields, respectively). These intermediate compounds [4 a] and E/Z-[5 a] were effectively transformed into the final product [6 a] on heating in wet xylene. An equilibrium constant K
E-Z for E-Z isomerization of [5 a] was 2.44 in refluxing dry tetrahydrofuran (THF) and the calculated ΔG
E→Z was 2.5 x 10
3 J⋅ K
-1mol
-1. Under the optimized conditions ([3]:[2]: [KF] =1: 3: 1; at -5°C for 3 h in THF, then refluxed for 6 h in xylene after quenching with water and replacement of the solvent), the reaction of [3a] or the methyl- or chloro-substituted analogs gave the corresponding 1 Hbenzo[c ]quinolizin-1-one derivatives [6a]-[6e] in 93 (substituent R =H), 92 (R =6-CH
, ), 83(R = 8 -CH
3), 90(R =8-Cl), 86%, (R =10-Cl) yields, respectively, and 5-methyl-3-pen tafluoroethyl2-trifluoromethyl-1 H-benzo[ c ]quinoxalizin-1-one [6 f] in 35% yield.
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Hidetake SAKURABA
1992 Volume 1992 Issue 12 Pages
1463-1469
Published: December 10, 1992
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Modified β-cyclodextrin-epichlorohydrin cross-linked polymer having hydrophobic cavities was prepared by the esterification of primary hydroxyl groups of B-cyclodextrin with 3, 4, 5trihydroxybenzoic acid (gallic acid) or 3, 4-dihydroxybenzoic acid (protocatechuic acid) activated by KF in DMF.
By compl exation with iron(III) ion, the polymers became a highly active catalyst for the hydroxylation of benzene with hydrogen peroxide in the range of pH 2-4 at room tempera ture under nitrogen atmosphere (conversion of 85-95%). At the optimum pH of 2.5, both catalysts gave catechol, hydroquinone, and phenol in the yields of 68-73, 7-8, and 10-14%, respectively. No resorcinol was detected in the products. The immobilized catalyst was easily separated from the reaction mixture, and was reused without decrease in catalytic activ ity.
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Shin'ichi TAKAO, Toshihiko SAKURAI, Matayoshi NAKAMURA
1992 Volume 1992 Issue 12 Pages
1470-1478
Published: December 10, 1992
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X-Ray absorption effects were studied to carry out the quantitative analysis of various asbestos fibers by using transmission electron microscope (TEM) equipped with energy dispersive spectrometry.
X-R ay intensities ratioed to Si for various standards appeared to have much variation in a diameter 0.1μm than in diameters from 0.5 to 1.0μm under the fixed operating conditions of impinging electron beam. It was possible to calculate absorption correction intensities by the linear regression line on fiber diameter vs. intensity ratio basis when the thickness can not be measured or intensity ratios are not much variable. In the linear regression line of absorption correction factor calculated on the basis of chemical compositions, the slope of Na that has a large mass absorption coefficient increased markedly in the presence of much amounts of Fe such as in crocidolite fiber.
The thickness of each fibe r was found to be smaller than its diameter observed by the TEM.
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Hidehiko MORI, Yoshikazu FUJIMURA, Makoto WATANABE, Makoto SAKURA, Hid ...
1992 Volume 1992 Issue 12 Pages
1479-1483
Published: December 10, 1992
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New chelate resins were prepared by the reaction of a diphenyl phosphonate-formaldehyde resin with polyamine. The adsorption and desorption of gold(III) with the present chelate resin were examined.
The prepa red resin modified with triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine have the high adsorption capacity (2.3 mmol Au/g-resin). Gold(M) is readily adsorbed on the resins as anionic chloro-complexes from hydrochloric acid solution. Adsorption rate of gold(11) is high and the gold(M) was adsorbed effectively by passing gold (III) solution (100 mgdm
-3) through the resin column at SV 600.1-cl. The presence of 0.5moldm-8 KH
2PO
4 at pH 4.2 or 0.2 moldm
-3 HNO
3 and the five-times amount of Cu(10, and Al(III) to gold(III) at pH O.5 do not affect the adsorption efficiency of gold(III). The gold(III) loaded on a column can be eluted with 0.5 moldm
-3 HCl-50 v/v% acetone aqueous solution.
The DPP-PEH resin loading gold(ll) which was treated with NaBH
4 in ethanol can be utilized as a catalyst for hydrogenation of acetylene.
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Yasuo SAITOH, Shinichi AKIMOTO, Kumiko EBINE
1992 Volume 1992 Issue 12 Pages
1484-1491
Published: December 10, 1992
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Selective conversion to useful syngas or methane of fuel soots impregnated with KOH was investigated in respect of air pollution or lowering engine efficiency. Reactant soot was prepared from propane gas and light oil fuel by flame incomplete combustion, and gasification, of these soots was performed using flow type reactor (U tube) under atmospheric pressure. Water gas reaction or shift reaction of the KOH-impregnated soots exhibited much higher as well as more stable gas evolution rate on steam-helium mixture stream than that of active carbon granule as reference carbon (550-700 °C). Gasificated products from these soot/KOH by steam were largely H
2, CO, CO
, and small amount of CH
, (under 1%).
It was found that the light oil-soot interacted strongly with KOH gave higher carbon consumption rate (138 g⋅l
-1⋅h
-1at 650 °C) as compared with that of gasoline fuel-soot (70g⋅l
-1⋅h
-1at 650 °C). Impregnation with KOH caused soot to promote increase in the surfa ce area at elevated temperature and to catalyze water gas reaction. The results presented on the products distribution and the gasification rate suggest that reduction-oxidation cycle of potassium was caused by the contact of carbon with water molecules at the elevated temperature. From the results of water gas reaction on K
2CO
3-impregnated soot and XRD it was infered that the gradual deactivation of KOH in the gasification of soot was due to the formation of K
2CO
3.
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Hidekazu NAGAI, Youkichi URANO, Kazuaki TOKUHASHI, Sadashige HORIGUCHI ...
1992 Volume 1992 Issue 12 Pages
1492-1500
Published: December 10, 1992
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The flammability limits of hydrogen are known to follow characteristic pressure dependence. The relationship between the limit flame temperature and pressure is determined according to the mechanism of flame quenching. In the present study, by using rather small sized vessels (20 mm and 35 mm in diameter), the flammability limits of hydrogen hae been measured at pressures of 1-50 kgf⋅cm
-2. The measurements have also been made to examine the effect of direction of flame propagation; upward, downward and horizontal propagations (Table 1). Pressure dependences of the limit flame temperature were analyzed, using equations which were derived from competitive reaction model and conductive heat loss model, f or upward propagation, and convection model for downward and horizontal propagations, respectively (Tables 2 and 3).
It has been found that the vessel size does not change much the pressure dependence of the lower flammability limits. On the other hand, the direction of flame propagation does change the lower limits, though the way is very similar for the two vessels (Figs.2 and 3). It seems that the mechanism which determines the lower limits of hydrogen is the competition between the chain branching and chain breaking reactions of hydrogen combustion.
As for the upper limits (Figs.4 and 5), the pressure dependence has been found to vary drastically according to the experimental conditions. The mechanism of the propagation limit seems to change for different propagation directions and for different pressure regions. For the lower pressure region, the pressure dependence of the limit flame temperature is well explained by the competitive reaction model. And for the higher pressure region, the heat l oss mechanism seems to be effective for upward propagation, and the convective mechanism seems responsible for both downward and horizontal propagations.
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Isao SANEMASA, Yuuki KOIDE, Toshio DEGUCHI
1992 Volume 1992 Issue 12 Pages
1501-1503
Published: December 10, 1992
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The complex formation of elemental mercury with α-, β-, and r-cyclodextrins (CDs) has b een studied in the excess of CD in aqueous medium at 25 °C. Solubility and volatilization methods were used to determine formation constants. The former method gave 4.5 dm
3⋅mol
-1and the latter 6 dm
3mol
-1 for the 1: 1 (α-CD: Hg) complex formati on. Both methods did not show any complex formation of Hg with β- and γ-CDs.
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Satoshi FUJII, Yosohiro SUGIE, Masafumi KOBUNE, Atuhiko Touno, Junichi ...
1992 Volume 1992 Issue 12 Pages
1504-1507
Published: December 10, 1992
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Uptakes of Cu
2+, Pb
2+ and Zn
2+ on various synthetic hydrotalcite (HT-0O
3, HT-SO
4, HTCl and HT-NO
, ) were investigated in Cu(NO
3)
2, Pb(NO
3)
2, Pb(NO
3)
2 and Zn(NO
3)
2 aqueous solution (each conc.: 2000 mgdm-3). Hudrotalcite has a pronounced activity for the uptakes of Cu
2+, Pb
2+ and Zn
2+. Amounts of Cu
2+, Pb
2+ and Zn
2+ removed by HT-0O
3 are about 1.7 mmol Cu/g, 1.0 mmol Pbfg -and 1.2 mmol Zn/g. In a mixed solution of Cu
2+, Pb
2+ and Zn
2+ (the concentration of each ions: 20 mmoldm
-3), the order of activity for the uptak es of each ions on HT-0O
3, HT-SO
4, HT-Cl and HT-NO, are Pb>Cu>Zn, Cu>Pb>Zn, Pb>Cu>Zn and Cu>Pb>Zn. When the HT-0O
3 was immersed into the Pb(NO
3)
2 solution, a part of the Me-, OH- and CO
3- of HT-CO
3 (Mg
6Al
2(0F1)
16CO
34 H
20) dissolve into the solution. The dissolved OH- and CO
32- causes the Pb
2+ to precipitate as Pb
3(OH)
2 (CO
3)
2 on the surface of the HT-CO
3.
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Jiro YAMAMOTO, Riyoen YAMAWAKIY, Yasunori Sumi, Riyuji OKAMOTO, Makoto ...
1992 Volume 1992 Issue 12 Pages
1508-1510
Published: December 10, 1992
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When the oxidation of 3-substituted 4'-methylazobenzene and 4'-substituted 4-methyl azobenzenes was carried out with hydrogen peroxide in acetic acid, two kind of isomers which differ the relative position of oxygen atom on nitrogen atoms were obtained in almost equimolar amounts.
_??_
β, α-Isomeric conversion of these 4-methylazoxybenzene deriva tives took place in the reaction of β-isomers with chromium(VI) chloride in acetic acid.
_??_
When Y is hydrogen, X are Cl, NO
2 and I and also X is hydrogen, X are NO
2, I and Br, respectively.
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Akira HASEGAWA
1992 Volume 1992 Issue 12 Pages
1511-1514
Published: December 10, 1992
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The alumina thin films with sponze-like surface structure were prepared by the sol-gel method using a 1, 3-butanediol solution of aluminium nitrate. The film usually produced by the spin-coating method and calcined at 500 °C (100 nm thick) has the homogeneous flat surface. However, the additional hot-water treatment at 100 °C for 2 h and calcination at 500 °C changed the surface texture to the sponze-like surface (Fig.3). The film was found to be covered with fibrillay particles of 50-100 nm in length and ca.5 nm in width which were composed of fine -Al
2O
3r particles with the mean size of ca.5 nm (Fig.4). The pores constructed by the aggregate of the fibrillay particles were observed in the range of 100-, 200 nm in diameter by SEM.
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Ichizo KOBAYASHI
1992 Volume 1992 Issue 12 Pages
1515-1517
Published: December 10, 1992
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Synthesis of highly pure dipivaloylmethane (Hdpm) chelates of Tantalum(V) was investigated. The chelates were synthesized by the reaction of the ligands with Tantalum pentachlcride using anhydrous solvents under high purity argon gas atmosphere.
[Ta(dpm)
4]Cl was syntesized as a new source material for p reparation of Ta
2O
5 thin films by MOCVD. [Ta(dpm)
4]Cl was in good agreement with the calculated value in the results of ICP and elemental analysis, and was confirmed by FT-IR,
1H-NMR,
13C-NMR, and TGDTA. Vaporization of impurities was not found in TG measurement. The tantalum complex vaporized in the range of 220 to 360 °C without residue.
[Ta(dpm)
4]Cl proved to be superior in volatility and purity for the MOCVD source material.
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