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81.
Jong‐Seong Kim Hyunchul Kim Jihwan Yoon Kyuyoung Heo Moonhor Ree 《Journal of polymer science. Part A, Polymer chemistry》2005,43(18):4079-4088
Various heterogeneous zinc glutarate (ZnGA) catalysts were synthesized in solvent systems of various polarities from zinc acetate dihydrate and glutaric acid with and without the aid of an amphiphilic block copolymer, poly(ethylene glycol‐b‐propylene glycol‐b‐ethylene glycol) (PE6400), as a template. The presence of the PE6400 template and the polarity of the solvent significantly affected the morphology, particle size, surface area, and crystallinity of the resulting catalyst. However, all the catalysts had the same crystal lattice unit cell structure and similar surface compositions. The surface compositions of the catalysts were quite different from those of conventionally prepared ZnGA catalysts, that is, those prepared from zinc oxide and glutaric acid in toluene. All these characteristics of the catalysts influenced the ZnGA‐catalyzed copolymerization of carbon dioxide and propylene oxide. The catalytic activities of the catalysts in this copolymerization depended primarily on their surface area and secondarily on their crystallinity; a larger surface area and a higher crystallinity resulted in higher catalytic activity. Of the catalysts that we prepared, the ZnGA catalyst that was prepared in ethanol containing 5.5 wt % water with the PE6400 template, ZnGA‐PE3, exhibited the highest catalytic activity in the copolymerization. The catalytic activity of ZnGA‐PE3 was attributed to its wrinkled petal bundle morphology, which provided a large surface area and high crystallinity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4079–4088, 2005 相似文献
82.
[reaction: see text] Syntheses of conduritols B-D and F and d-(+)-chiro- and neo-inositols from cyclohexenylsilane intermediates are described. The key cyclohexylsilane intermediates 5 and 14 were synthesized by stereoselective olefin dihydroxylation of the corresponding cyclohexenylsilanes. Selective Peterson elimination reactions and Fleming-Tamao oxidations of 5 and 14 then delivered the targeted cyclitol derivatives. 相似文献
83.
Organoindium reagents derived from indium and diethyl bromomalonates were added to a wide range of conjugated enones in a 1,4-fashion in the presence of TMSCl under mild conditions, and corresponding oxo-1,3-diesters were obtained in good to excellent yields. 相似文献
84.
Preparation of cholesteric liquid crystal microcapsules for application in colour image storage media 总被引:1,自引:0,他引:1
Cholesteric liquid crystal (CLC) microcapsules for application in image storage media can be obtained via a diffusion-controlled polymerization method (DPM). To improve the swelling of the CLC seed particle, in poly(methylmethacrylate) (PMMA), a polymerizable acrylate based on a cholesterol moiety was synthesized and copolymerized with MMA to prepare the seed particle. As a result, monodispersed and CLC core/shell-structured microcapsules may be obtained. The resulting CLC microcapsules selectively, absorbed visible light at around 660 nm, and so appeared blue in the mesophase. Polymer dispersed cholesteric liquid crystal (PDCLC) cells were prepared using the CLC microcapsules, and were used as an image storage medium in reversible writing/erasing experiments. 相似文献
85.
Single-stage anaerobic codigestion for mixture wastes of simulated Korean food waste and waste activated sludge 总被引:2,自引:0,他引:2
Nam Hyo Heo Soon Chul Park Jin Suk Lee Ho Kang Don Hee Park 《Applied biochemistry and biotechnology》2003,107(1-3):567-579
Korean food waste was treated with a single-stage anaerobic codigester (SSAD) using waste activated sludge (WAS) generated
from a municipal wastewater treatment plant. The stability and performance of the system was analyzed. The C/N ratio was improved
with increasing food waste fraction of feed mixture. The pH, alkalinity, and free ammonia nitrogen concentration were the
parameters used to evaluate the digester’s stability. The experimentally determined values of the parameters indicated that
there were no methane inhibitions in the digester. Digester performance was determined by measuring the total chemical oxygen
demand TCOD), volate solids (VS) removal, methane content in biogas, methane production rate (MPR), and specific methane productivity.
Methane content in biogas and MPR were significantly dependent on hydraulic retention time (HRT) and ratio of food waste to
WAS. The methane content in biogas decreased at shorter HRT or higher organic loading rate (OLR) with increased food waste
fraction. Concerning the performance of the codigester, the optimum operating condition of the SSAD was found to be at an
HRT of 10 d with a feed mixture ratio of 50% food waste and 50% WAS. A TCOD removal efficiency of 53.6% and a VS removal efficiency
of 53.7% were obtained at an OLR of 5.96 kg of TCOD/(m3·d) and 3.14 kg of VS/(m3·d), respectively. A maximum MPR of 1.15 m3 CH4/(m3·d) and an SMP of 0.37 m3 CH4/kg of VSfeed were obtained at an HRT of 10 d with a methane content of 63%. 相似文献
86.
Lee SK Heo S Lee JG Kang KT Kumazawa K Nishida K Shimbo Y Takanishi Y Watanabe J Doi T Takahashi T Takezoe H 《Journal of the American Chemical Society》2005,127(31):11085-11091
Two chiral bent-core mesogens Pn-O-PIMB(n - 2)* (n = 9 and 10) and their oxygen analogues Pn-O-PIMB(n - 2)*-(n - 4)O (n = 8, 9, and 10) with omega-[(S)-amyloxy]alkoxy terminal groups were prepared, and their phase structures were investigated by means of electro-optic, polarization reversal current and second harmonic generation measurements in order to clarify the effect of the interlayer steric interaction on the emergence of polar orderings. The odd-even behavior for the alternative appearance of ferroelectricity and antiferroelectricity was observed in two homologous series; the bent-core mesogens P10-O-PIMB8*, P8-O-PIMB6*-4O, and P10-O-PIMB8*-6O in addition to the previously reported P6-O-PIMB4* and P8-O-PIMB6*, where the length of chains n is even, exhibited ferroelectric phases. On the contrary, the mesogens P7-O-PIMB5*, P9-O-PIMB7*, and P9-O-PIMB7*-5O, where n is odd, showed antiferroelectric phases. It is obvious that the interlayer steric interaction plays a major role for the emergence of a variety of phase structures. 相似文献
87.
Ruthenium-promoted intramolecular S(N)Ar reaction has allowed the construction of the fully functionalized 16-membered DEF macrocycle 4 of ristocetin A that incorporates the required arylglycine and arylserine residues as the F and E ring, respectively. 相似文献
88.
Jungseok Heo Soo‐Young Kim Dongmok Whang Kimoon Kim 《Angewandte Chemie (International ed. in English)》1999,38(5):641-643
A honeycomb structure is shown by the one‐dimensional coordination polymer comprising D6h‐symmetric cucurbituril molecules and rubidium ions (see picture). The cucurbituril molecules stack atop one another and show coordination of their carbonyl groups to the rubidium ions in between. The shape and symmetry of the building blocks encourage the coordination polymer chains to be arranged in such a way as to produce an open‐framework structure with large, linear, hexagonal channels. 相似文献
89.
A range of neutral metal-organometallic coordination networks (MOMNs) containing both backbone and pendant metal sites have been synthesized and characterized. These materials consist of metal ions or metal ion clusters as nodes that are linked by the bifunctional “organometalloligand” (η4-benzoquinone)Mn(CO)3−, which binds through the quinone oxygen atoms. The resulting MOMNs can be rationally designed to a significant extent based upon a knowledge of the electronic and geometrical requirements of the metal ion nodes, the solvent, organometalloligand substituents, and the presence or absence of organic spacers. An impressive range of architectures have been accessed in this manner, suggesting that the use of π-organometallics in coordination directed self-assembly holds much promise. 相似文献
90.