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971.
Kang‐Ying Li Zheng‐Hong Zhou Li‐Xin Wang Guo‐Feng Zhao Michael C. K. Choi Qi‐Lin Zhou Chu‐Chi Tang 《Heteroatom Chemistry》2003,14(3):288-291
Synthesis of several new chiral phosphinamide catalysts with a proximal hydroxyl group from L ‐serine was described. These compounds have been successfully used in the asymmetric catalytic borane reduction of prochiral ketones. The optically active secondary alcohols were obtained with an enantiomeric excess (ee) up to 81% and excellent yields. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:288–291, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10145 相似文献
972.
Young Gun Ko Ung Su Choi Tai Young Kim Dong June Ahn Yong Jin Chun 《Macromolecular rapid communications》2002,23(9):535-539
A new chelating fiber, poly(acrylo‐amidino diethylenediamine), was synthesized based on polyacrylonitrile fibers in diethylenetriamine with the aid of AlCl3. Complex formation with CrO42– was strongly pH‐dependent, as complexes formed only in the presence of NH3+ and NH2+. In the medium pH region, both ionic and hydrogen bonds were formed between poly(acrylo‐amidino diethylenediamine) and the chromate ion, as was confirmed by means of FT‐IR spectroscopy. 相似文献
973.
974.
Fumio Sanda Tsuyoshi Shinjo Wonmun Choi Takeshi Endo 《Macromolecular rapid communications》2001,22(5):363-366
This article deals with the cationic and anionic depolymerization of polydithiocarbonate, which was synthesized by cationic polymerization of 5‐phenoxymethyl‐1,3‐oxathiolane‐2‐thione ( 1 ) using methyl triflate as the initiator. The cationic depolymerization of the obtained polymer was carried out in the presence of 5–20 mol‐% of methyl triflate or triflic acid catalyst in chlorobenzene at 60 °C for 96 h to afford 4‐phenoxymethyl‐1,3‐dithiolan‐2‐one ( 2 ) in 35–83% yield. The anionic depolymerization of the polymer was carried out in the presence of 5 mol‐% of triethylamine or potassium tert‐butoxide at 20 °C for 24 h to afford 2 in 85–100% yield. 相似文献
975.
The synthesis of the first lactose main‐chain copolymer was achieved by means of solution polyreaction of ethylenediaminetetraacetic acid dianhydride with D ‐lactose. The water‐soluble carboxy‐functional material based on EDTA with a high molar mass is shown to be biodegradable. The metal complexing properties of the polymer based on the liquid‐phase polymer‐based retention (LPR) method showed a strong interaction with Cr(III), Fe(III), and Sr(II) ions. 相似文献
976.
Rupasree R. Das Shashadhar Samal Seok‐Ju Choi Kurt E. Geckeler 《Macromolecular rapid communications》2001,22(11):850-854
The synthesis of a novel highly swelling, macroporous hydrogel from poly(allylamine) using 3‐chloropentan‐2,4‐dione as a crosslinker is reported. The swelling of the hydrogel was sensitive to changes in pH, temperature, and the extent of crosslinking. The dry gel exhibited a regular honeycomb network with smooth macropores. The hydrogel was inherently luminescent, and so was a metal polychelate. 相似文献
977.
978.
Alexander Steblyanko Wonmun Choi Fumio Sanda Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2000,38(13):2375-2380
A bifunctional five‐membered cyclic carbonate was synthesized from carbon dioxide and diglycidyl terephthalate, and its polyaddition with alkyl diamines were carried out in DMF at room temperature to obtain the corresponding poly(hydroxyurethane)s with Mn s in the range of 6300–13200 in good yields. The structures of the obtained polymers were confirmed by IR and NMR spectroscopy and their glass‐transition and decomposition temperatures were observed at 3–29 °C and 182–277 °C, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2375–2380, 2000 相似文献
979.
Young Gun Ko Ung Su Choi Byeng Gil Ahn Dong June Ahn 《Journal of polymer science. Part A, Polymer chemistry》2000,38(15):2815-2823
High‐performance materials for flameproofing, phosphates (polyphosphate and ammonium phosphate) were synthesized on viscose rayon felt. This surface reaction has the advantage of a nonblooming effect and an application in thermosetting plastics. Metal complexes have the effect of reducing the amount of smoke. Therefore, in the second step, transition‐metal complexes were synthesized on the viscose rayon ammonium phosphate felt. This article focuses on the surface modification of phosphates and metal complexes on viscose rayon. All reactions were confirmed by attenuated total reflectance Fourier transform infrared and time‐of‐flight secondary ion mass spectrometry. As the concentrations of phosphoric acid and urea increased, the peak intensities of ammonium ion groups and phosphate groups greatly increased. The thermal properties of the synthesized materials were studied with thermogravimetric analysis and oxygen index testing. On the basis of the experimental results, the synthesized flame‐retardancy materials showed excellent physicochemical and thermal effects and flame retardancy. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2815–2823, 2000 相似文献
980.