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41.
Himeda Y Onozawa-Komatsuzaki N Sugihara H Kasuga K 《Journal of the American Chemical Society》2005,127(38):13118-13119
The catalyst recycling in the conversion of CO2 into formate using the iridium complex with 4,7-dihydroxy-1,10-phenanthroline as a catalyst precursor is described. The catalyst precursor was dissolved in an aqueous KOH solution under CO2 pressure prior to the reaction, but was precipitated spontaneously at the end of the reaction. The acidification by the generation of formate caused the transformation from the water-soluble deprotonated form into the water-insoluble protonated form. When the reaction was carried out at 60 degrees C for 20 h using 0.1 M KOH solution under 6 MPa of H2:CO2 (1:1), the catalyst precursor was precipitated spontaneously and the added KOH was consumed completely. The catalyst was recovered by filtration, and the product was obtained by the evaporation of the filtrate. Iridium leaching into the filtrate was found to be 0.11 ppm (<2% of the loaded Ir). The recovered catalyst retained high catalytic activity for four cycles. Consequently, the CO2 conversion using the complex is an environmentally benign process, whose significant features are as follows: (i) catalyst recycling by self-precipitation/filtration, (ii) waste-free process, (iii) the easy isolation of the product, (iv) high efficiency under relatively mild conditions, and (v) aqueous catalysis without the use of organic materials. Furthermore, we have demonstrated the significant roles of the oxyanion generated from the acidic phenolic hydroxyl on the catalyst ligand, which are the catalyst recovery by acid-base equilibrium, as well as the water-solubility by its polarity and the catalyst activation by its electron-donating ability. 相似文献
42.
Catalytic effect of nanoparticle 3d-transition metals on hydrogen storage properties in magnesium hydride MgH2 prepared by mechanical milling 总被引:1,自引:0,他引:1
We examined the catalytic effect of nanoparticle 3d-transition metals on hydrogen desorption (HD) properties of MgH(2) prepared by mechanical ball milling method. All the MgH(2) composites prepared by adding a small amount of nanoparticle Fe(nano), Co(nano), Ni(nano), and Cu(nano) metals and by ball milling for 2 h showed much better HD properties than the pure ball-milled MgH(2) itself. In particular, the 2 mol % Ni(nano)-doped MgH(2) composite prepared by soft milling for a short milling time of 15 min under a slow milling revolution speed of 200 rpm shows the most superior hydrogen storage properties: A large amount of hydrogen ( approximately 6.5 wt %) is desorbed in the temperature range from 150 to 250 degrees C at a heating rate of 5 degrees C/min under He gas flow with no partial pressure of hydrogen. The EDX micrographs corresponding to Mg and Ni elemental profiles indicated that nanoparticle Ni metals as catalyst homogeneously dispersed on the surface of MgH(2). In addition, it was confirmed that the product revealed good reversible hydriding/dehydriding cycles even at 150 degrees C. The hydrogen desorption kinetics of catalyzed and noncatalyzed MgH(2) could be understood by a modified first-order reaction model, in which the surface condition was taken into account. 相似文献
43.
π-Cyclopentadienylbis(tri-n-butylphosphine)nickel chloride reacts with sodium benzenesulfinate and sodium p-toluenesulfinate in aqueous solution at room temperature to give π-cyclopentadienyl-S-(benzenesulfinato) (tri-n-butylphosphine)nickel, π-C5H5Ni(PBu3)SO2Ph and π-cyclopentadienyl-S-(p-toluenesulfinato)(tri-n-butylphosphine)nickel, π-C5H5Ni(PBu3)SO2C6H4CH3-p,-respectively. It reacts similarly with sodium benzenethiolate and sodium α-toluenethiolate in aqueous solution at room temperature to give π-cyclopentadienyl(benzenethiolato)(tri-n-butylphosphine) nickel, π-C5H5Ni(PBu3)SPh and π-cyclopentadienyl(α-toluenethiolate)(tri-n-butylphosphine)nickel, π-C5H5Ni(PBu3)SCH2Ph, respectively. 相似文献
44.
Zhou M Tsumori N Xu Q Kushto GP Andrews L 《Journal of the American Chemical Society》2003,125(37):11371-11378
Reactions of boron atoms and clusters with NO molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. The reaction products were identified by isotopic substitution ((10)B, (11)B, (15)N(16)O, (14)N(18)O, and mixtures) and comparison with density functional calculations of isotopic frequencies. In solid argon, boron atoms spontaneously reacted with NO to form the insertion molecule NBO. The BNBO and OBNNO molecules were formed by the B and NO addition reactions to NBO. The linear BBNO and BBBNO nitrosyls also were formed spontaneously on annealing. These molecules photochemically rearranged to the more stable BNBO and BNBBO isomers, which have linear polyyne-like structures. The photosensitive OBNNO molecule decomposed to form the NNBO(2) van der Waals complex. In addition, the novel OBON diradical was also formed on photolysis in high-concentration NO experiments. 相似文献
45.
A novel neutral glycosphingolipid found in Microcosmus sulcatus containing a β-d-Galp(1→4)[α-d-Fucp-(1→3)]β-d-Glcp-(1→)Cer motif was synthesized. Trisaccharide derivatives were synthesized using trimethylsilyltrifluoromethanesulfanate (TMSOTf) and N-iodosuccimide (NIS)/trifluoromethane sulfonic acid (TfOH) as the promoters. Synthesis was achieved with an efficient one-pot glycosylation strategy. This is the first report of a one-pot glycosylation strategy using the procedure of Boons et al. for the synthesis of a natural product. Coupling of trisaccharide derivative 19 and ceramide derivative 20 by TMSOTf afforded the glycosphingolipid derivative 21. The fully protected glycoside was deprotected to give the target glycosphingolipid 2. 相似文献
46.
47.
Nobuko Yoshimoto Osamu Shimamura Takuya Nishimura Minato Egashira Maiko Nishioka Masayuki Morita 《Electrochemistry communications》2009,11(2):481-483
A novel polymeric electrolyte based on a self-assembled copolymer moiety has been prepared by a simple method of photo-induced radical polymerization of a mixture consisting of stearylmethacrylate (SMA) and poly(ethylene glycol)-monomethacrylate (PEM) that dissolves LiBF4 as the electrolytic salt. The SMA moiety work as mechanically stable backbone and the PEM unit dissolving the salts serves as ion-conducting path in the polymeric composite. Solid-state NMR measurements indicated that the resulting polymer composite consists of PEM-rich and SMA-rich phases, each of which exists within several nanometers apart. The ionic conductivity of the polymer electrolyte with the composition of PEM/SMA = 7/3 (by mass ratio) was 2.8 × 10?5 S cm?1 at 50 °C, which was significantly higher than that of the polymer electrolyte based on cross-linked PEM copolymer without SMA. 相似文献
48.
Okuda M Suzumoto Y Iwahori K Kang S Uchida M Douglas T Yamashita I 《Chemical communications (Cambridge, England)》2010,46(46):8797-8799
We report here, for the first time, a biotemplated synthesis of uniform CdSe nanoparticle (4.1 ± 0.5 nm) and a fabrication of two-dimensional CdSe nanoparticles (over one micrometre) with nanometric gaps by cage-like protein, Listeria-Dps. 相似文献
49.
A series of "organic chemical hydrides" such as cyclohexane, methylcyclohexane, cyclohexene, 2-propanol, and cyclohexanol were applied to the direct PEM fuel cell. High performances of the PEM fuel cell were achieved by using cyclohexane (OCV = 920 mV, PD(max) = 15 mW cm(-2)) and 2-propanol (OCV = 790 mV, PD(max) = 78 mW cm(-2)) as fuels without CO(2) emissions. The rates of fuel crossover for cyclohexane, 2-propanol, and methanol were estimated, and the rates of fuel permeation of cyclohexane and 2-propanol were lower than that of methanol. Water electrolysis and electro-reductive hydrogenation of acetone mediated by PEM were carried out and formation of 2-propanol in cathode side was observed. This system is the first example of a "rechargeable" direct fuel cell. 相似文献
50.
Masayoshi Okubo Toyoko Suzuki Reiko Shinohara Nobuko Fukami 《Colloid and polymer science》2002,280(11):1053-1056
The adsorption behavior of poly(oxyethylene) nonyl phenyl ether nonionic emulsifier molecules onto polystyrene (PS) and styrene-methacrylic acid copolymer [P(S-MAA)] particles dispersed in D2O was evaluated by in situ 1H NMR measurements at room temperature. The resonance due to the protons of the emulsifier molecules was only observed. Normalized NMR integrals of the resonance due to the protons of hydrophobic groups (nonyl and phenyl groups) and the hydrophilic group, poly(oxyethylene) chain, at a certain concentration of the emulsifier decreased with an increase in the total surface area of the PS particles dispersed in the system. The decrease for the hydrophobic groups was much larger than that for the hydrophilic groups. In the dispersion system of P(S-MAA) particles, ionized carboxyl groups at the particle surface decreased the amount of the emulsifier adsorbed. 相似文献