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161.
Condensation of fluorine-containing anilines with paraldehyde gave quinaldine derivatives with CF3, CF3S, and CF3SO2 groups in the 6 position, from which carbocyanine, merocyanine, and styryl dyes were synthesized. Fluorine-containing groups lower the basicity of quinaldine by 0.7–2.0 pKa units and lead to deepening of the color of the dyes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 76–78, January, 1978. 相似文献
162.
T. F. Sysoeva Z. A. Starikova S. D. Ershova N. M. Dyatlova 《Journal of Structural Chemistry》1991,32(2):293-296
All-Union Scientific-Research Institute of Chemical Reagents and Ultrapure Chemical Substances. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 2, pp. 163–166, March–April, 1991. 相似文献
163.
164.
165.
R. Kh. Dadashev Kh. B. Khokonov D. Z. Elimkhanov Z. I. Bichueva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(7):1181-1183
A surface tension isotherm equation for ternary systems was derived based on general thermodynamic expressions with consideration for the concentration dependence of the molar surface area. Within the experimental errors, the equation describes the properties of ternary systems with smooth surface tension isotherms. 相似文献
166.
The thermal stabilities of two series of segmented polyurethane fibres have been compared with their chemical structure. The polyurethanes were synthesized from trimethylene diamine; 4, 4′ diphenylmethane di-isocyanate and two polyether based macrodi-isocyanates. Thermal stability was measured by thermogravimetric analysis and differential thermal analysis. By comparing the changes in weight loss and DTA peaks with chemical structure it has been found possible to separate soft segment from hard segment degradation.In the initial stages stability increases as soft segment concentration increases while the reverse is true in the later stages of degradation. The 100% soft segment polymer (polytetrahydrofuran) and the 100% hard segment polymer appear to behave anomalously. It is suggested that the hard segment has a stabilizing influence on the degradation of the soft segment. The results are discussed in the light of various theories of polyurethane degradation. 相似文献
167.
S. D. Fazylov A. M. Gazaliev M. Zh. Zhurinov R. Z. Kasenov A. B. Tateeva M. Z. Kokzhalova 《Chemistry of Natural Compounds》1994,30(3):371-372
The results are given of the synthesis and a comparative study of the toxicities of some phosphorylated derivatives of the
alkaloids l-ephedrine and d-pseudoephedrine. It has been shown that the introduction of phosphorus- and sulfur-containing
fragments considerably lowers the toxicity of the alkaloids.
Institute of Organic Synthesis and Coal Chemistry, National Academy of Sciences of the Republic of Kazakhstan, Karaganda.
Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 406–408, May–June, 1994. 相似文献
168.
O. G. Yarosh Z. G. Ivanova T. D. Burnashova M. G. Voronkov 《Russian Chemical Bulletin》1984,33(11):2394-2396
Conclusions The reaction of magnesium bromide derivatives of di- and triethynylsilanes with dimethylethynylfluorosilane gave 1,2-disubstituted silylacetylenes containing ethynyl and vinyl groups at the silicon atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2614–2616, November, 1984. 相似文献
169.
Z. G. Aliev L. O. Atovmyan A. M. Sipyagin V. G. Kartsev O. V. Dobrokhotova 《Chemistry of Heterocyclic Compounds》1987,23(4):390-395
A one-step synthesis of azetidin-3-ones by intramolecular cyclization of 1-diazo-3-arenesulfamoylalkan-2-ones was developed. The yield of cyclic product increases to 70% in the presence of an alkyl or benzyl substituent in the hydrocarbon chain of the diazoketone. The structure of N-tosyl-2-ethylazetidin-3-one was studied by x-ray diffraction analysis and it was shown that the four-membered ring has 15 inflection.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–473, April, 1987. 相似文献
170.
A model describing the wetting of structural elements in polycrystals such as grain boundaries (faces), triple lines (edges), and quaternary nodes (vertices) is proposed. It is assumed that the only driving force during wetting is the tendency of a system to the energy minimization due to the substitution of low-energy liquid–solid interfaces for high-energy grain boundaries. In this case, the anisotropy of grain boundary energy caused by the differences in misorientation of adjacent grains is taken into account, whereas the liquid–solid interface energy is assumed to be independent of the orientation. The well-known condition of grain boundary wetting (the Gibbs–Smith condition) is extended to the triple lines and quaternary nodes by introducing parameters determined as characteristic free energy of these elements. 相似文献