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151.
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153.
We have developed a three-dimensional passive micromixer based on new mixing principles, fluid twisting and flattening. This
micromixer is constructed by repeating two microchannel segments, a “main channel” and a “flattened channel”, which are very
different in size and are arranged perpendicularly. At the intersection of these segments the fluid inside the micromixer
is twisted and then, in the flattened channel, the diffusion length is greatly reduced, achieving high mixing efficiency.
Several types of micromixer were fabricated and the effect of microchannel geometry on mixing performance was evaluated. We
also integrated this micromixer with a miniaturized DNA purification device, in which the concentration of the buffer solution
could be rapidly changed, to perform DNA purification based on solid-phase extraction. 相似文献
154.
Masumi?Itazaki Yasushi?Nishihara Kohtaro?OsakadaEmail author 《Transition Metal Chemistry》2005,30(7):828-830
Reaction of PPh2H with Pd(PPh3)4 in a 4:1 molar ratio produced the Pd complex with two diphenylphosphine ligands, Pd(PPh2H)2(PPh3)2 (1). Complex (1) was characterized by n.m.r. (1H and 31P{1H}) spectra as well as by elemental analysis. Reaction of (1) with RhCl(PPh3)3 yielded a Pd–Rh heterobimetallic complex with bridging phosphide ligands, formulated as [(Ph3P)2Pd(μ-PPh2)2Rh(PPh3)2]Cl (2). 相似文献
155.
Takashi Matsuda Yoko Asoh Masumi Villeneuve Hiroki Matsubara Takanori Takiue Makoto Aratono 《Colloid and polymer science》2004,282(4):324-329
The ion–dipole interaction between dodecyltrimethylammonium cations and nonionic surfactant molecules in adsorbed films and micelles was investigated by concentrating on the difference in the degree of counterion binding by employing dodecyltrimethylammonium chloride (DTAC)–octyl methyl sulfoxide (OMS) and dodecyltrimethylammonium bromide (DTAB)–OMS mixtures. The phase diagrams of adsorption and micelle formation were constructed and then the nonideal mixing of different species of surfactants was demonstrated in terms of the excess Gibbs free energies of adsorption and micelle formation, and the surface excess areas. Furthermore the dependence of them on the counterion was clearly shown. All these results were found to support our previous view that the direct interaction between surfactant cation and the dipole of the hydrophilic part of a nonionic surfactant is essential in cationic-nonionic surfactant mixtures, i.e., the DTAC system with a lower counterion biding has more negative excess thermodynamic quantities than the DTAB system with a higher one. 相似文献
156.
The first example of the catalytic C? CN bond cleavage of acetonitrile as well as Si? CN bond formation have been achieved in the photoreaction of MeCN with Et3SiH promoted by [Cp(CO)2FeMe]. This catalytic system is applicable to other organonitriles. Several iron complexes [(η5‐C5R5)(CO)2FeR′] (R5=H5, H4Me, Me5, H4SiMe3, H4I, H4P(O)(OMe)2; R′=SiMe3, CH2Ph, Me, Cl, I) were examined as catalyst, and [Cp(CO)2FeMe] was found to be the best precursor. A catalytic reaction cycle was proposed, which involves oxidative addition of Et3SiH to [Cp(CO)FeMe], reductive elimination of CH4 from [Cp(CO)FeMe(H)(SiEt3)], coordination of RCN to [Cp(CO)Fe(SiEt3)], silyl migration from Fe to N in the coordinated RCN, and dissociation of Et3SiNC from Fe. The reaction with MeCN of [Cp(CO)Fe(py)(SiEt3)], which was newly prepared and determined by X‐ray analysis, and the reaction of Et3SiH with MeCN in the presence of a catalytic amount of [Cp(CO)Fe(py)(SiEt3)] showed that the 16‐electron species [Cp(CO)Fe(SiEt3)] is the active species in the catalytic cycle (TON up to 251). 相似文献
157.
Masao Morimoto Atsushi Yamakawa Hiroshi Katagiri Kenichi Sakai 《Tetrahedron: Asymmetry》2007,18(24):2869-2875
The resolution of racemic 1-benzyl-5-oxo-3-pyrrolidinecarboxylic acid 1, a potent chiral synthon with high pharmacological activity, was investigated with a variety of basic chiral resolving agents via diastereomeric salt formation. The findings in the optimization of resolution conditions aiming at an industrial-scale production revealed that (S)-phenylalanine benzylamide (S)-10 and 2-propanol containing ca. 4 mol % of water to (RS)-1 were the best conditions for obtaining enantiopure less-soluble diastereomeric salt, (S)-1/(S)-10/0.5H2O (81%, 98% de, E 79%). X-ray crystallographic analysis of the salt clearly revealed that water molecules play a key role in crystallizing the enantiopure salt crystals, while stabilizing the crystal structure via three types of hydrogen-bond network associated with water molecules in addition to usual acid–base hydrogen bond. 相似文献
158.
Enantioselective Cyanosilylation of Ketones with Lithium(I) Dicyanotrimethylsilicate(IV) Catalyzed by a Chiral Lithium(I) Phosphoryl Phenoxide
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Dr. Manabu Hatano Katsuya Yamakawa Tomoaki Kawai Dr. Takahiro Horibe Prof. Dr. Kazuaki Ishihara 《Angewandte Chemie (International ed. in English)》2016,55(12):4021-4025
A highly enantioselective cyanosilylation of ketones was developed by using a chiral lithium(I) phosphoryl phenoxide aqua complex as an acid/base cooperative catalyst. The pentacoordinate silicate generated in situ from Me3SiCN/LiCN acts as an extremely reactive cyano reagent. Described is a 30 gram scale reaction and the synthesis of the key precursor to (+)‐13‐hydroxyisocyclocelabenzine. 相似文献
159.
Miyake H Hikita M Itazaki M Nakazawa H Sugimoto H Tsukube H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(18):5393-5396
160.
Masumi Takamura Tomoyuki Nakamura Kiyohito Koyama 《Polymer Degradation and Stability》2008,93(10):1909-1916
Poly(l-lactide) (PLLA) was cross-linked with various types of peroxides under constant mole ratios of peroxide-derived radicals to PLLA during reactive extrusion. Peroxides were classified into three groups according to their decomposition rates (Group I: fast, Group II: moderate and Group III: slow) and comparisons were performed within each group. Cross-linking behavior was readily understood in terms of free radical efficiency and hydrogen abstraction ability of radicals. In the case of Groups II and III, the weight-average molecular weight (Mw) of cross-linked PLLA increased with overall hydrogen abstraction ability, because slow decomposition caused uniform cross-linking in molten PLLA. In Group I, Mw and gel fraction were higher than other groups despite Group I's lower hydrogen abstraction ability, leading to the conclusion that peroxide decomposition localized in solid PLLA caused partial cross-linking because of rapid decomposition. Furthermore, the efficiency of peroxide-induced cross-linking was investigated using the Charlesby-Pinner equation. 相似文献