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31.
Arata Aota Kazuma Mawatari Susumu Takahashi Teruki Matsumoto Kazuteru Kanda Ryo Anraku Akihide Hibara Manabu Tokeshi Takehiko Kitamori 《Mikrochimica acta》2009,164(3-4):249-255
Phase separation of gas–liquid and liquid–liquid microflows in microchannels were examined and characterized by interfacial pressure balance. We considered the conditions of the phase separation, where the phase separation requires a single phase flow in each output of the microchannel. As the interfacial pressure, we considered the pressure difference between the two phases due to pressure loss in each phase and the Laplace pressure generated by the interfacial tension at the interface between the separated phases. When the pressure difference between the two phases is balanced by the Laplace pressure, the contact line between the two phases is static. Since the contact angle characterizing the Laplace pressure is restricted to values between the advancing and receding contact angles, the Laplace pressure has a limit. When the pressure difference between the two phases exceeds the limiting Laplace pressure, one of the phases leaks into the output channel of the other phase, and the phase separation fails. In order to experimentally verify this physical picture, microchips were used having a width of 215 μm and a depth of 34 μm for the liquid–liquid microflows, a width of 100 μm and a depth of 45 μm for the gas–liquid microflows. The experimental results of the liquid–liquid microflows agreed well with the model whilst that of the gas–liquid microflows did not agree with the model because of the compressive properties of the gas phase and evaporation of the liquid phase. The model is useful for general liquid–liquid microflows in continuous flow chemical processing. 相似文献
32.
Arata Yajima Yuuma Kagohara Keisuke Shikai Ryo Katsuta Tomoo Nukada 《Tetrahedron》2012,68(6):1729-1735
The synthesis of two potent osteoclast-forming suppressing agents isolated from the Chinese mushroom Agrocybe chaxingu, demethylincisterol A3 and chaxine A, was accomplished using ergocalciferol as the starting material. Our methodology for the synthesis of demethylincisterol A3 and chaxine A featured the construction of a butenolide moiety by the intramolecular Horner–Wadsworth–Emmons reaction under Masamune–Roush conditions. This is the first reported synthesis of chaxine A. 相似文献
33.
A highly active catalyst for the skeletal isomerization of butane to isobutane was obtained by mechanically mixing SO4/ZrO2 and Ru/SnO2; Ru/SO2 was prepared by impregnating tin hydroxide with a solution of RuCl3 followed by calcining at 450°C (0.5 wt.% Ru). The catalyst was much more active than Ru-SO4/ZrO2 prepared by co-impregnation of zirconia with the Ru and sulfate materials the temperature difference to show the same conversion between both catalysts being 57°C. The effect of mixing of Ru was observed with other metal oxides as supports, Fe2O3, Al2O3, ZrO2, TiO2, and SiO2; the calcination temperature of the Ru-impregnated hydroxides was 250, 300, and 400°C for the latter three, respectively. 相似文献
34.
Teruaki Suzuki Minoru Suzuki Akio Furusaki Takaheshi Matsumoto Arata Kato Yoshihiko Imanaka Etsuro Kurosawa 《Tetrahedron letters》1985,26(10):1329-1332
Two new cyclic ethers consisting of squalene carbon skeleton have been isolated from the red alga L. obtusa. The absolute stereostructure of teurilene () was elucidated by x-ray crystallographic method, and the structure of thyrsiferyl 23-acetate () was established from the spectral and chemical evidence. 相似文献
35.
The spectroscopic constants of s-trans (E)-acrylaldehyde oxime of normal, CH2CHCHNOH, and deuterated, CH2CHCHNOD, species were refined by adding a-type R-branch transitions observed in the frequency range of 34-40 GHz in the ground vibrational state. For s-trans (Z) form, the spectroscopic constants of normal species were refined by refitting the reported frequencies with four b-type Q-branch transitions and those of deuterated species were determined by the least-squares fitting of the observed a-type R-branch transitions in the ground vibrational state. The spectroscopic constants of two isomers of normal species were also determined in the vibrationally excited states. The inertial defects (ΔI=Ic−Ia−Ib) of normal and deuterated species were determined to be −0.042(24) and −0.064(17) u Å2 for s-trans (E)-1 form, and −0.0536(8) and −0.063(11) u Å2 for s-trans (Z)-1 form, respectively. From the rs coordinates of the hydroxyl hydrogen atom determined for s-trans (Z)-1 form, its OH bond was concluded to be at the trans position with respect to the CN double bond. The dipole moments of deuterated species of s-trans (E)-1 form and those of normal and deuterated species of s-trans (Z)-1 form were determined. The structural parameters of r(C2C3), ∠C1C2C3, ∠C2C3N, and ∠C3NO for s-trans (E)-1 and s-trans (Z)-1 forms were adjusted separately using to their rotational constants observed. It was found that the bond angle of ∠C2C3N in s-trans (Z)-1 form are much wider than that in s-trans (E)-1 form by about 10°. The difference between the observed and calculated (using MP2/6-311++G (d,p) level) rotational constants of s-trans (Z)-1 form was larger than that of s-trans (E)-1 form. 相似文献
36.
Ryo Katsuta Hiroki Ichijo Ginka Oouchi Arata Yajima Ken Ishigami Tomoo Nukada 《Tetrahedron letters》2018,59(24):2352-2355
An efficient synthetic pathway to acylpyrrolidinones via a nitro-Mannich reaction, followed by the intramolecular 1,3-dipolar cycloaddition of a nitrile oxide to an alkyne was developed. The syntheses of a leucine-derived tetramic acid and natural tetramide (+)-laccarin were achieved in five steps using aldehydes, 2-alkynamides and nitromethane as the carbon sources. 相似文献
37.
38.
The α-alkyl β-oxoesters undergo type II photoreactions. The process of back hydrogen transfer in the 1,4-biradical intermediate to revert to the starting ester is suppressed because of the intramolecular hydrogen bonding between the hydroxyl and carboalkoxyl groups in the biradical intermediate. The hydrogen bonding determines the stereochemistry of 1,4-biradical cyclization. The cyclobutanols having the hydroxyl group cis to the carboalkoxyl group are formed exclusively from the α-alkyl β-oxoesters . The enol form of the type II elimination product, the benzoylacetate , acts as an effective internal filter for the photoreaction of the α-alkyl β-oxoester . 相似文献
39.
Rigid diol bearing 6‐6‐6 fused ring system derived from naturally occurring myo‐inositol and its polyaddition with diisocyanates
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Arata Yoshida Atsushi Sudo 《Journal of polymer science. Part A, Polymer chemistry》2017,55(22):3798-3803
Naturally occurring myo‐inositol was developed into a highly rigid diol by converting its 3,4‐ and 1,6‐vicinal diols in trans configuration into the corresponding butane‐2,3‐diacetals. The resulting diol bearing 6‐6‐6 fused ring system, in which conformational change is strictly suppressed, was combined with diisocyanates to perform polyadditions. The resulting polyurethanes were analyzed by differential scanning calorimetry, and it was found that their glass transition temperatures were much higher than those of the previously reported myo‐inositol‐derived polyurethanes, which were synthesized from a myo‐inositol‐derived diol bearing 5‐6‐5 fused ring system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3798–3803 相似文献
40.