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871.
A. B. Terentiev T. T. Vasilieva N. A. Kuz'mina S. A. Orlova N. S. Ikonnikov E. I. Mysov E. Kolehmainen K. Laihia Yu. N. Belokon 《Russian Chemical Bulletin》1996,45(3):676-679
The addition of methyl (S)-2-bromopropionate to trimethylvinylsilane initiated by systems based on iron pentacarbonyl affords a racemic adduct and is accompanied by racemization of the unreacted chiral ester. In the presence of benzoyl peroxide, the reaction proceeds similarly, but no racemization of the starting chiral ester occurs.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 715–718, March, 1996. 相似文献
872.
In view of the nonlinear variation of the temperature increments ofn-alkanes found previously, the accuracy of the calculations of the retention indices (I
pr) of substances in temperature-programmed capillary gas chromatography carried out in terms of six known equations was verified.
A new four-parameter equation was proposed, and a general method for the calculation of its coefficients, suitable for all
stationary phases, based on the adjusted retention times ofn-alkanes was suggested. The coefficients of the equation for 12 temperature variation programs were determined. Using the
homologous series of methyl esters of fatty acids as an example, it was shown that the proposed equation ensures the minimum
error of determination ofI
pr under various conditions. The equation also makes it possible to carry out interpolation and extrapolation calculations.
The coefficients of the equation are found using the least-squares method based on data for any 4–5 referencen-alkanes.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 323–327, February, 1997. 相似文献
873.
Toru Takagishi Young Joo Kim Toshitsugu Hosokawa Keiji Morimoto Kenji Kono 《Journal of polymer science. Part A, Polymer chemistry》1993,31(2):365-371
The copolymers of methyl quaternized 2-dimethylaminoethyl acrylate and styrene, 2-vinyl naphthalene, acrylic acid iso-octyl ester, or acrylic acid n-butyl ester have been prepared. Studies were made of the binding of a “binding probe,” methyl orange, by the copolymers in aqueous solution. The first binding constants and the thermodynamic parameters in the course of the binding were evaluated. Furthermore, the intensity of fluorescence of a hydrophobic fluorescent probe, 2-p-toluidinylnaphthalene-6-sulfonate, in the presence of these polymers was investigated. In addition, the fluorescence spectra of monomer and excimer emissions of the polymers with aromatic residues were measured. The excimer/monomer fluorescence intensity ratio was studied in the presence of various additives such as methyl orange, urea, methanol, and NaCl to gain an insight into the nature of microdomains in the polymer. The nature and phenomena of dye binding and hydrophobic fluorescent probe binding with the polymers are discussed. © 1993 John Wiley & Sons, Inc. 相似文献
874.
T. E. Kuzmenko A. L. Samusenko V. P. Uralets R. V. Golovnya 《Journal of separation science》1979,2(1):43-44
An injection splitter in front of a glass capillary column was used for the hydrogenation of fatty acid methyl esters (FAME) mixtures. Hydrogenation followed by gas chromatographic analysis on capillary columns permitted detection and identification in complicated natural mixtures of branched fatty acids, showing minor structural differences, in quantities down to 10?8g. The technique described, apart from its suitability for FAME analysis, shows promise for structure determination studies of other classes of compounds. 相似文献
875.
CHEN Wei-zhu GAO Yu-xing BAI Yong-gang HAN Da-xiong ZHAO Yu-fen 《高等学校化学研究》2006,22(6):732-737
Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation pathways were investigated, and it was observed that most fragment ions contained the phosphoryl group. It was interesting to observe that the fragmentation pathways of the protonated molecule show some differences when compared with those of the sodium ion adduct. The methoxy group of amino acid methyl ester can migrate from the carbonyl group to the phosphoryl group in the sodium ion adduct. 相似文献
876.
COMPATIBILITY IN POLYMER BLENDS OF POLY (VINYL ACETATE) AND POLY (METHYL METHACRYLATE)STUDIED BY NMR
Compatibility of poly (vinyl acetate) (PVAc) with poly (methyl methacrylate) (PMMA) mixtures has been studied by using nuclear magnetic relaxation, differential scanning calorimeter and small-angle X-ray scattering techniques. The nuclear magnetic relaxation time T_1's were measured as a function of composition in blends of PMMA and PVAc prepared from chloroform solution. The results show that the system is miscible for casting from chloroform solution. 相似文献
877.
STUDY ON SEGMENTED POLYURETHANE WITH MIXED SOFT SEGMENTS OF POLYCHLOROMETHYL METHYL SILOXANE AND POLYTETRAMETHYLENE OXIDE 总被引:2,自引:0,他引:2
Two series of polyurethanes based on mixed polychloromethyl methyl siloxane and poly-tetramethylene oxide in different weight fractions were synthesized. The phase separation ofsamples was studied using DSC and dynamic mechanical property analysis. The results showedthat the introduction of chloromethyl group into polysiloxane increased its polarity and henceimproved the miscibilities with polytetramethylene oxide and polyurethane hard segment.Particularly, in the case of N-methyldiethanolamine extended materials, the surface and tensileproperties of these samples can be adjusted by various ratios of two soft segments. 相似文献
878.
Sun?Y.?Park Min?S.?Cho Chul?A.?Kim Hyoung?J.?ChoiEmail author Myung?S.?Jhon 《Colloid and polymer science》2003,282(2):198-202
Microspheres consisting of a poly(methyl methacrylate) (PMMA) shell wrapping the conductive polyaniline (PANI) particle as a core were prepared by an in-situ suspension polymerization method and then adopted as an electrorheological (ER) material. The polymerization reaction and encapsulation were confirmed by Fourier transform infrared spectrum analysis. The rod-like PANI particles were synthesized via an emulsion polymerization protocol and observed by transmission electron microscopy. In addition, a spherical shape of encapsulated PANI/PMMA (core/shell) microspheres was observed by scanning electron microscopy. The thermal stability of PANI/PMMA particles was examined by use of thermogravimetric analysis. The PANI/PMMA particle-based suspension in silicone oil exhibited typical ER behavior. The conductivity of PANI/PMMA particles was much lower than that of the rod-like PANI. 相似文献
879.
4—取代苯基—6—甲基—5—硫代—1,2,4—三嗪—3—酮的合成 总被引:3,自引:0,他引:3
合成了一系列新的4,6-二取代-5-硫代-1,2,4-三嗪-3-酮类化合物,并用元素分析、IR、^1H NMR及MS对其结构进行了表征。 相似文献
880.
Wataru Sakai Akira Tsuchida Masahide Yamamoto Jun Yamauchi 《Journal of polymer science. Part A, Polymer chemistry》1995,33(12):1969-1978
The main chain scission reaction of poly(methyl methacrylate) (PMMA) doped with N,N,N,′,N′-tetramethyl-p-phenylenediamine (TMPD) was examined by ESR spectroscopy and GPC measurement, and the scission mechanism was analyzed. The two-photon ionization of TMPD with excimer laser excitation at 77 K produced an ester radical anion of PMMA (PMMA·m?), which becomes the main chain tertiary radical ? CH2? C˙(CH3)? CH2? after the detachment of the ester side group by annealing of the sample at room temperature. The main chain scission radical ˙C(CH3)(COOCH3)? (PMMA˙) which was produced by the β-scission from? CH2? ˙C(CH3)? CH2? showed the 13-line ESR spectrum instead of the ordinary 9-line, due to the fast quenching of the sample to 77 K. The change of the molecular weight distribution was measured by GPC after several irradiation-and-annealing operations. The simulation of the GPC curve confirmed that the scission re-action occurs at random in the PMMA chain in the solid and the main chain scission yield from the ester radical anion, [PMMA˙]/[PMMA·m?], is 0.30. © 1995 John Wiley & Sons, Inc. 相似文献