A stable precursor solution for SiO2 film formation was prepared from the reaction of tetraethoxysilane with glucose in ethanol, by the regulation of the hydrolysis of the alkoxide through the complex formation of the sugar toward Si. The resulting solution involving diethylamine could be spin-coated on a quartz glass with excellent coatability. By firing the precursor film at above 600 degreesC, transparent and crack-free film with ca. 500 nm thickness was obtained. The precursor solution has a long-term stability. By the XPS spectra of the films formed at 600 and 1000 degreesC, it was elucidated that the nitrogen atoms were completely removed from the precursor films. Thermal properties of the precursor powders obtained from the solution were also examined by TG-DTA. Au-dispersed SiO2 films with several An content ratios of Au/Si in the range from 0.01 to 0.1 were also prepared by the application of the precursor solution. Graft-polymer stabilized Au clusters in ethanol were well dispersed into the SiO2 precursor solution. The SiO2 precursor solution added with An clusters, could be spin-coated on a quartz glass with excellent coatability. Blue shifts of the maximal positions of the absorption band due to the surface plasmon resonance of Au clusters were observed, in the absorption spectra of the Au-dispersed SiO2 films. By the XRD spectra of the SiO2 film with dispersed An clusters, it was elucidated that the crystallite size of the Au clusters does not depend on the contents.
In order to catch the characteristic of the flow at saline wedge, the experiment for occurrence and flowing of saline wedge using a rectangular open channel was performed. Saline wedge is generally so stable that the visual observations are easy, and interfacial layers are measured with the aid of visualization method. As a result of the experiment, it was found that a saline wedge was reproduced well, and the form of tip of saline wedge changed by relative density and the amount of discharge on the upper reaches. It was also found that the thickness of the downstream freshwater depth was dependent upon the number of Richardson. The degrees of the dilution near the separation point could be displayed at the function with F-io in the density layer.
The electrolyte matrix of Molten Carbonate Fuel Cells (MCFC) is generally reinforced with a mixture of alumina fibers to provide strength within the cell. However, alumina fibers corrode and are changed into lithium aluminate by reaction with lithium carbonate in molten carbonate. Lithium aluminate have two crystal structures in molten carbonate, alpha-phase and gamma-phase. It is known that lithium aluminate undergo mutual crystal structure transformations between alpha- and gamma-phase in molten carbonate. Therefore, the stability of electrolyte matrix is lowered. It is reported recently that alpha-lithium aluminate is more stable than gamma-phase in molten carbonate. We have studied on a-lithium aluminate fiber instead of alumina fiber. We synthesized it at low temperature under CO2 atmosphere by the solid state reaction of gamma-alumina fiber with lithium carbonate. Further, it was found that a-lithium aluminate fiber was synthesized with keeping fiber structure. The evaluation of stability of this fiber in molten carbonate were performed by comparing with alumina fiber. The mixture of alpha-lithium aluminate fiber and alpha-lithium aluminate powder was stable and the crystal structure of this mixture remained alpha-lithium aluminate. It can be expected that application of alpha-lithium aluminate fiber instead of alumina fiber improve the stability of the electrolyte matrix for MCFC.
Antioxidative effects of Taheebo extract, obtained from the bulk of Tabebuia avellanedae Lorents and Griseb, were examined by two assay methods for radical scavenging activity on DPPH and inhibitory effect on linoleic acid peroxidation. In the case of the DPPH method, Taheebo showed the electron donating ability to DPPH and its ability corresponded to that of trolox in the present experimantal condition. On the other hand, in the autoxidation of liloleic acid, Taheebo extract showed the most inhibitory effect in teas tested (green tea and oolong tea.). These results suggested that Taheebo extract was a desirable antioxidant.
An effective synthesis of a series of fluorine-containing polyfunctional aromatic compounds, 4-halo-3-trifluoromethylbenzonitriles 1a-c was performed by the use of some tetrahedral copper-cyano complexes as Sandmeyer cyanating reagents and sublimation in the isolation and purification process. In the conversion of the corresponding diazonium salts to the target benzonitrile derivatives (1a-c), three tetrahedral tetracyanocopper complexes, K-3[Cu(CN)(4)], Na-3[Cu(CN)(4)], and K-2[Cu(CN)(4) . NH3], proved to be effective as Sandmeyer cyanating reagents though copper( I) cyanide gave the target compounds in moderate yields. Furthermore, the yields of nitriles la-c in the reaction with the copper (I) complexes were rather higher than that with the copper (II) complex, K-2[Cu(CN)(4) . NH3]. The conversion reactions to nitriles 1a-c are suggested to proceed through an SNAr mechanism.
The six modified beta-cyclodextrin (beta-CD) derivatives, which have neighboring phenolic oxygens (GA, PA, NH-PA and 2,3-HBA), one phenolic oxygen (SA) and no phenolic oxygen (BA), were synthesized, and the catalytic activity of their transition metal ion complexes in the asymmetric oxidation of aromatic sulfides having phenyl, naphthyl, and phenanthryl rings was examined in the pH range of 1-7. The hydroxy groups attached at the 3,4 and 5 positions of the phenyl ring in the polyphenol-appended beta-CD derivatives were found effective for the asymmetric oxidation of methyl 1-naphthyl sulfide in the presence of Mo(V) ion at pH of 6 to form the corresponding (R)-sulfoxide preferentially in the optical yields of 20-55%. Conversely use of the beta-CD derivatives with the phenolic hydroxy group at position of 2 resulted in the formation of (S)-sulfoxide in 19-35% ee. The optical yields also depend on the bridging group with which the 3,4-dihydroxybenzoyl group (PA) is bound to the primary C-6 position of beta-CD, that is, the Mo (V) complex of beta-CD-PA (ester bonding, optical yield 55%: the highest ee value obtained by the oxidation of methyl 1-naphthyl sulfide in a series of aromatic sulfides) shows higher stereoselectively than that of beta-CD-NH-PA (amide bonding, 41% ee). No chiral induction is observed in the presence of beta-CD-BA which has no phenolic hydroxy group. The complexes of beta-CD-PAA with Mo and W (4d- and 5d-blocks) metal ions accelerate the formation of (R)-sulfoxide with 36-55% ee, while those with 3d-block metal ions favor the (S)-sulfoxide production with 10-45% ee.
On D-lactose, C-6 and C-6' which have the primary hydroxy groups were selectively triphenylmethylated and the remaining secondary hydroxy groups were acetylated. During detriphenylmethylation, acyl migration occurred to give acetylated lactose having free hydroxy groups on C-6 and C-46'. Polycondensation of the obtained 1,2,3,2',3',6'-hexa-O-acetyl-D-lactose and terephthaloyl chloride gave the aromatic polyester having lactose in the main chain.
We analyzed UV absorption, fluorescence and circular dichroism spectra of the title compounds, as well as their fluorescence lifetimes, in the presence of beta-cyclodextrin (beta-CDx) or gamma-cyclodextrin (gamma-CDx). The beta-CDx cavity turned out to axially incorporate the naphthalene ring of the model 2-naphthylalanine derivative to exert its effect so as to significantly decrease the fluorescence quenching rate. This finding provides a strong piece of evidence for a "through space" mechanism by which the emission quenching occurs. On the other hand, the naphthalene ring of the 1-naphthylalanine derivative was suggested to be immersed into the gamma-CDx cavity in both axial and equatorial modes resulting in a less significant decrease of the fluorescence quenching rate.
Catalytic NO2 removal by activated carbon loading Ag, Pt, Cu and CuO has been studied. In this experiment, activated carbon from coconut shells was used after washing with 1 mol dm(-3) HCl and water. Activated carbon lording metals was prepared by adsorbing metal complexes (H2PtCl6, Cu-II-picolinate) or metal ion (Ag+), followed by heating the activated carbon at 700degreesC in N-2 atmosphere. Copper(II) oxide on activated carbon (CuO/AC) was prepared by heating the Cu/AC at 400degreesC in air. Nitrogen dioxide was generated by decomposition of Pb (NO3)(2) at 550degreesC and circulated in a catalyst column packed with activated carbon (Fig. 1). Nitrogen dioxide was highly removed by Pt/AC, Cu/AC and CuO/AC in air or nitrogen atmosphere but less by Ag/AC (Fig. 3, 4). After the removal of NO2, very small amounts of HNO3, HNO2, NO and NH3 existed in the gas phase and the increase in N-contents on activated carbon was small (Table 1). From the XRD patterns of activated carbon after removal of NO2, it was suggested that the oxidation state of Pt was not changed but the peak height decreased (Fig. 5). On the other hand, XRD patters of Cu/AC and CuO/AC indicated the presence of Cu, Cu2O and CuO in air and Cu and Cu2O in N-2 atmosphere (Fig. 6, 7). These results indicate that activated carbon loading Pt or Cu is a good catalyst for removal of NO2 and NO2 may be reduced to N2 by catalysis of Pt, Cu or Cu2O.
Smectite clays were examined as catalysts for the alkylation of diphenyl oxide with long-chain olefins in liquid phase. A clay treated with sulfuric acid was characterized to have a mesopore structure and found to act as an efficient catalyst especially in the alkylation of a hindered substrate. Thus the clay can be used as a substitute for AlCl(3). Saponite with a card-house structure showed the catalytic activity similar to that of a Y-type zeolite. On the other hand, a sheet type clay (Al-Mont) showed similar activity with the acid-treated one (H-Mont) when heated at around 120 degreesC but lost its activity when heated at higher temperature probably because of the sheet shrinking. The following relationship between the pore size of catalyst and product distribution was noted. The catalysts with a wider pore size tend to produce more polyalkylated products and ortho isomers. Isomer distribution of arylated alkanes spread wider in the p-isomer than those in the o-isomer, which can be explained in terms of steric hindrance and olefin isomerization during the reaction. Mordenite with one dimensional micropore channel structure showed a high selectivity toward straight shape molecules. From the viewpoint of products selectivity, smectite clays were situated between homogeneous and micropore-heterogeneous catalysts, and was found to be useful for alkylation of a bulky substrate.
alpha-Methoxycarboxylic acids 1 undergo decarbonylative alpha,alpha-diarylation reaction with arenes 2 in the presence of phosphorus pentoxide-methanesulfonic acid mixture (P2O5-MsOH). However, 2-methoxyacetic acid (1d) shows different reaction behavior from those of other alpha-carboxylic acids (1). Trifluoromethanesulfonic acid (TfOH)-mediated reaction of 2-methoxyacetic acid (1d) with arenes 2 yields anthracene derivatives 10 in addition to Friedel-Crafts acylation type products and diarylmethanes 4. The reaction behavior was elucidated by estimating the influence of the kind of acidic medium and the substrate structure. Furthermore, based on the results of the reaction of the model compounds for the corresponding suspected reaction pathways, the adequacy of the pathways was evaluated. TfOH-mediated reactions of 2-methoxyacetic acid (1d) with arenes except for that with benzene (2f) proved to proceed via alpha-hydroxyacetophenone homologues 7 and 11, 1,1-diarylethanediol derivatives 14, and 1,2,2-triarylethanol derivative 17.
The polymerization of cyclic ethers initiated by the reaction of cyclic ethers with hexafluoropropylene oxide (HFPO) were examined.When tetrahydropyrane (THP) was used as a monomer, the polymer could not be obtained. When oxetane was used as a monomer, both yield and molecular weight of the obtained polymer were higher than those obtained in the polymerization using the other cyclic ethers as monomers. This is probably due to the highest homopolymerization reactivity of oxetane of the comonomers used.The polymer obtained in the polymerization of PO had the different structure from that of the other polymers. The steric bulkiness and occurring of both alpha-and beta-ring cleavage of PO probably lead to specific structure of the resulting polymer.
In-flight carbonization was tried by introducing spherical phenolic resin powders of average particle size, approximate to 25 mum, into RF induction thermal plasma. The carbon powder was composed of highly porous particles and of the gradient structure with respect to porosity and crystal structure. The layered structure in the surface region was highly graphitized surface, while the core was amorphous. The structure was attributed to the unique nature of thermal plasma processing. Electrochemical measurements as the anode of lithium rechargeable battery also showed the insertion reaction of lithium into the graphitized and amorphous regions.
The molecular assemblies of photosynthetic reaction centers (RCs) driving the light-to-redox energy conversion have been studied by chemical analytical and various spectroscopic means. As a result, one molecule of chlorophyll (Chl) a', the C13(2)-epimer of the dominant pigment Chl a, was detected for the first time as an essential component of photosystem I RC of higher plants, algae, and cyanobacteria. Further, two molecules each of bacteriochlorophyll (BChl) g' and 8(1)-OH-Chl a in heliobacterial RCs, two molecules of BChl a' in the RC of a green sulfur bacterium Chlorobium tepidum, and one or two molecules of Chl d' in the RC of a cyanobacterium Acaryochloris marina were detected. In addition, the chemical structure of BChl 663, the primary acceptor in the RC of green sulfur bacteria, and that of Zn-BChl a found in Acidiphilium rubrum, were determined. Detection/identification of these novel minor but key pigments would contribute to the discussion on the molecular machinery of photosynthetic reaction centers.
examined the repetitive "KUROME" of raw urushi in a reaction vessel for the purpose of refining the polymerized urushi liquid that has a natural drying property in a low humidity environment. Namely, we evaluated the polymerization apparatus of the urushi liquid as a simple experiment. The raw urushi was polymerized by the repetitive "KUROME" process in a traditional method. We also examined the change in urushiol and the drying property in a low humidity environment (20-25 degreesC, 45-55%RH).Raw urushi undergoes enzymic oxidization by repetitive "KUROME" and decreases the urushiol monomer. Also, in this reaction, we developed a relation formula because there is a correlation in the area of the reaction vessel base, processing quantity and also processing time. Furthermore, with these changes, it was determined that the hydroxy value and anti-oxidization power decrease and the autoxidation of the side chain more easily occurs.
Callus cultures of Taxus cuspidata were induced from young stems in a modified Gamborg B5 medium with various known auxines. Taxol(R) (Paclitaxel) (1) (0.010% based on dry callus weight) and its relating compounds containing oxetane ring 7-10 were isolated from the fast-growing callus cultures (CR-5 cell strain) with NAA 0.5 mg/L in the medium, together with taxuyunnanine C (2) and its 14-acyloxy derivatives 3-6 in high yields (total 0.49%). The dry callus culture was extracted with hexane, ethyl acetate, and methyl alcohol successively. These extracts were separated by the combination of silica gel flash chromatography and HPLC. Taxol (1), 7-epitaxol (7), and taxol C (8) were isolated from the extracts of EtOAc and MeOH in 0.010%, 0.002%, and 0.001% yields, respectively. Taxuyunnanine C (2) and its 14-acyloxy derivatives 3, 4, 5 and 6 were obtained from these extracts in 0.135%, 0.014%, 0.009%, 0.275% and 0.053% yields respectively.
Partial reduction of highly reactive NiAl2O4 Spinel was investigated concerning with the raw spinel powder prepared by thermal decomposition of Al-2(SO4)(3)-NiSO4 solid solutions. Solid solution of Al-2(SO4)(3) with NiSO4 was prepared from mixed aqueous solutions by a rapid dry using micro wave heating. The Ni2+ ion is soluble in the anhydrous aluminum sulfate crystal lattice over a wide range up to 65 mol % of (NiSO4) / (NiSO4 + Al-2(SO4)(3)). The anhydrous sulfate thermally decomposed to form the crystalline phases of spinel, eta-Al2O3 and NiO at 900 degreesC. The lattice parameter of the spinel changed linearly with the Ni content ranging from about 20 mol% to 50 mol% of (NiO) / (NiO + Al2O3) without any other crystalline phases coexisted. The compacted NiAl2O4 spinel powder buried in a carbon powder was heated to partially reduce. On heating up to 700 degreesC the NiO segregated from the spinel leading to its enrichment in Al2O3. Metal Ni appeared above 800 degreesC, coexisting with the NiO and the spinel. The lattice parameter of the spinel decreased with decreasing the content of Ni in the spinel. The alpha-Al2O3/Ni composite was formed after heating at 1300 degreesC, while three phases of the NiO, the metal Ni and the spinel were coexisted until heating at 1200 degreesC.
Under nitrogen atmosphere diethyl maleate was hydrogenated to give diethyl succinate in a high yield with metallic nickel/Zn/H2O/EtOH catalyst system in the presence of a large amount of zinc powder and water. Metallic nickel was an active species for the hydrogenation and zinc powder and water were reagents to produce hydrogen. Benzylideneaniline was hydrogenated to give N-phenylbenzylamine in a moderate yield under the reaction conditions and it was appreciably hydrolyzed to afford aniline and benzaldehyde at the same time.
As a new method to measure ice packing factor (IPF) in ice-on-coil type statical ice storage tank, electric-conductivity sensing of aqueous solution coexisting with ice was investigated in view point of application to district cooling and heating systems. Ice forming and melting process was monitored by measurements of total volume and electric-conductivity of the aqueous solution-ice mixture inside the test apparatus.The correlations between two IPF values determined by changes in volume and the electric-conductivity were obtained by changing kind of electrolyte, initial concentration of electrolyte in the solution, and ice formation rate. When a low ice formation rate corresponding to the operation condition for actual ice storage tank systems was chosen, it was found that the electrolyte in the solution was concentrated almost ideally with growth of ice. The specific electric-conductivity and concentration ratio have a linear correlation. Good linear correlation of two determination methods for IPF demonstrates that this new determination method based on electric-conductivity has sufficient accuracy and utility on the condition that good mixing is performed and concentration of electrolyte is equal or higher than that in tap water.
Previously we reported regioselective formation of dianions derived from liner nitroalkanes in the presence of n-BuLi and HMPA. The formation of nitroalkane dianions either alpha, alpha- or alpha, beta-dianions depended on the order of addition of reagents.However, the usage of a carcinogen suspected compound like HMPA is undesirable. Therefore we reinvestigated the new combination of bases and aprotic dipolar solvents other than HMPA.After exploration of a variety of their combination, it was found that the combination of LDA and DMPU resulted in the formation of alpha, beta-dianion with the best regioselectivity; the ratio of alpha- to beta-adduct was 1 to 14 in the reaction of nitroethane with benzaldehyde.
