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71.
The fundamental properties and extraction capability of an ionic liquid (IL), trioctylammonium nitrate ([HTOA][NO3]), for PdII and PtIV, are investigated. At room temperature, [HTOA][NO3] is a solid (melting point: 30.7 °C), but it becomes a liquid (melting point: 16.7 °C) when saturated with water. Water-saturated [HTOA][NO3] exhibits a viscosity of 267.1 mPa·s and an aqueous solubility of 2.821?×?10?4 mol·dm?3 at 25 °C, and can be used as an extraction solvent without dilution. [HTOA][NO3] exhibits an extremely high extraction capability for PdII and PtIV in dilute hydrochloric acid (0.1–2 mol·dm?3 HCl); the distribution ratio reaches 3 × 104 for both the metals. From electrospray ionization mass spectrometry analysis, the species extracted in the IL phase are [PdCl3]? and [PdCl2(NO3)]? for PdII and [PtCl6]2? and [PtCl5]? for PtIV. A majority of the other transition metals are considerably less or marginally extracted into [HTOA][NO3] from a 0.1 mol·dm?3 hydrochloric acid solution. The extraction capacity of [HTOA][NO3] is greater than that of other hydrophobic ILs such as [HTOA]Cl and bis(trifluoromethanesulfonyl)imide-based ILs. The metals extracted into the IL phase are quantitatively back-extracted using an aqueous solution containing thiourea and nitric acid. By controlling the thiourea concentration and shaking time, PdII and PtIV are mutually separated to some extent in the back extraction process. The IL phase used for the back extraction can be reused for the forward extraction of these metals after scrubbing it with an aqueous nitric acid solution. 相似文献
72.
Katsuhiro Mizoguchi Shoichi Tsuji Eishun Tsuchida Isao Shinohara 《Journal of polymer science. Part A, Polymer chemistry》1978,16(12):3259-3274
The chemical and electrical stabilities of 7,7,8,8-tetracyanoquinodimethane (TCNQ) salts composed of neutral TCNQ (TCNQ?), anion radicals of TCNQ(TCNQ?·), and polycation polymers were studied by measuring their electronic spectra and resistivities (ρ). The results of spectral and chemical analyses confirmed that TCNQ?· in TCNQ salts was decomposed to α,α-dicyano-p-toluoylcyanide (DTC?) as the final product by the intermediate formation of TCNQ? and p-phenylenediamalononitrile (H2TCNQ) and that H2O played an important part in the reaction. From these results it was concluded that TCNQ salts are decomposed by two reaction processes: The resistivity of TCNQ salts increases with the decomposition of TCNQ?·. Studies on electroconductivity of TCNQ salts assume that the change in resistivity arises from the loss of unpaired electrons which become conduction carriers and also from the disintegration of the TCNQ? and TCNQ?· complex which forms the conduction path. 相似文献
73.
Masahiro Imoto Hiroyuki Yoshimura Nobuki Sakaguchi Shoichi Kusumoto Tetsuo Shiba 《Tetrahedron letters》1985,26(12):1545-1548
The first total synthesis of E. coli lipid A () is described. The synthetic compound was identical with a natural specimen and exhibited the full endotoxic activity. It was thus conclusively proved by this chemical synthesis that lipid A is the active principle of bacterial endotoxin. 相似文献
74.
75.
Stereospecific reversible deactivation radical polymerization of biomass‐based acrylates for precise control of tacticity and molecular weight 下载免费PDF全文
Hitoshi Tanaka Tatsuya Kibayashi Kazuya Okuda Shoichi Kashihara 《Journal of polymer science. Part A, Polymer chemistry》2017,55(3):445-456
Reversible deactivation radical polymerization (RDRP) of biomass‐based acrylates, (S )‐ and (R )‐2‐isopropyl‐5‐methylene‐1,3‐dioxolan‐4‐ones (S‐MiPDO and R‐MiPDO), was successfully performed to produce a well‐defined polymer with simultaneously controlled tacticity and molecular weight, and low dispersity (? < 1.3). In particular, meso triad (mm ) of the polymer was continuously controlled as designed from 28.1% to about 100% by changing the molar ratio of S‐MiPDO/R‐MiPDO in feed. In kinetic studies, the rate of RDRP was strongly influenced by the stereostructures of the propagating radical, and it was much lower in isospecific RDRP than atactic one in reversible chain transfer catalyzed polymerization (RTCP) in contrast to atom transfer radical polymerization (ATRP) where the rate would not change regardless of the tacticity. Increase of molecular weight and low ? of the polymer were also observed in reversible addition‐fragmentation chain transfer (RAFT) polymerization of MiPDO. In addition, block copolymers including stereoblock copolymers were feasibly synthesized by RTCP of styrene and methyl methacrylate using poly(MiPDO) prepolymer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 445–456 相似文献
76.
Tetsuya Nanba Shoichi Masukawa Junko Uchisawa Akira Obuchi 《Journal of Thermal Analysis and Calorimetry》2013,113(2):793-802
We studied the temperature-programmed reduction by NH3 (NH3-TPR) as a supplement to the temperature-programmed reduction by H2 (H2-TPR) for the characterization of supported Cu species. The NH3-TPR profile of Cu/SiO2, which contained only bulk CuO, exhibited two peaks for N2 formation in equal amounts, suggesting stepwise reduction of the bulk CuO. In contrast, the H2-TPR profile exhibited only one H2 consumption peak. We also studied Cu-NaZSM-5 samples with various Cu and Na loadings. The Cu ions on ZSM-5 were reduced to Cu+ but no further. Kinetic analysis revealed that the NH3-TPR profile exhibited peaks for separate reductions of isolated and binuclear Cu2+ ions. Thus, we found NH3-TPR to be useful for detailed analysis of the reducibility of Cu2+ to Cu+ in zeolite pores. 相似文献
77.
The formation of the liquid crystal phase of a surface-active dye, p-octylphenol yellow amine poly(ethylene oxide), in aqueous methanol solutions has been examined by optical microscopy. Rodlike swarms appear at relatively low dye concentrations only slightly higher than the second critical micelle concentration. They develop into liquid crystal phase when the dye concentration is further increased. It takes some hours for the formation of a stripe-like texture characteristic of nematic liquid crystals, depending on the methanol content and dye concentration. The combination of the surface active-part and the azobenzene moiety would be responsible for the formation of the liquid crystal. 相似文献
78.
Abstract Mesomorphic phase transitions of 4′-n-alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC) with numbers of carbons (n) in the alkoxy group ranging from 11 to 22 have been studied by differential scanning calorimetry (DSC) and polarizing optical microscopy. The D phase, a mesophase of particular interest through its being optically isotropic, was observed for the n = 17, 19, 20, 21, and 22 members of the ANBCs, as well as for the n = 16 and 18 members, as reported previously. The Sc-D phase transition temperature decreased with increasing n, so that the temperature range of the D phase extended over 64° at n = 22. In the n = 15 member, the D phase was certainly observed on first heating, but was not seen on subsequent cooling and second heating processes. 相似文献
79.
The phase behaviour of a thermotropic cubic mesogen of 1,2-bis(4′-n-tetradecyloxybenzoyl)hydrazine BABH-14 was studied under hydrostatic pressure using a polarising optical microscope equipped with a high-pressure optical cell, and the P–T phase diagram was constructed. BABH-14 shows the Cr–Cub–I transition sequence under atmospheric and lower pressures, but the Cub phase is replaced completely by the high-pressure SmC, SmC(hp), phase under higher pressures. There is a narrow intermediate-pressure region between the low- and high-pressure regions, in which the Cr–SmC(hp)–Cub–I phase sequence is recognised. The SmC(hp)–Cub transition line has a positive slope with pressure and there are two triple points: one is for the Cr, Cub and SmC(hp) phases and the other is for the I, Cub and SmC(hp) phases. Comparing the phase sequence of BABH-14 with those for BABH-8 and -10, the pressure-induced inversion of the phase sequence between the cubic and SmC phases occurs in the BABH-n homologous compounds. Another new phenomenon is the formation of the monotropic cubic phase on cooling in the intermediate- and high-pressure regions, and an intriguing phenomenon of the cubic phase appearing twice, i.e. I–Cub–SmC(hp)– Cub–Cr phase transition, occurs in the intermediate-pressure region. 相似文献
80.