全文获取类型
收费全文 | 65篇 |
免费 | 0篇 |
专业分类
化学 | 50篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 6篇 |
物理学 | 6篇 |
出版年
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 7篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 31 毫秒
1.
Structure and Stability of Quaternary Ammonium Interhalides: Experimental and Quantum-Chemical Study
Simonyan S. S. Kletskii M. E. Chernov'yants M. S. Gol'eva V. E. 《Russian Journal of General Chemistry》2003,73(4):575-582
The electronic structure of a series of ammonium interhalides [R1R2R3R4N]XI2, where R1 = CH3, C2H5, C3H7, F, H; R2 = R3 = R4 = CH3, H; X = Cl, Br, I, was studied by ab initio calculations (RHF/3-21G, RHF/HW, MP2/HW). The thermodynamic stability of these compounds correlates with the strength of the hydrogen bond N-H···X and three-center interhalide bond X-I-I. Calculations confirmed that, in polar solvents, these compounds preferably decompose to [R1R2R3R4N]+ and XI2
- (with subsequent decomposition of the anion), and in nonpolar solvents, to the neutral species [R1R2R3R4N]X and I2. The calculation results were compared to the experimental data obtained by single crystal X-ray diffraction, 1H NMR spectroscopy, and spectrophotometry. 相似文献
2.
Simonyan G. S. Beileryan N. M. Arutyunyan R. S. Roque J.-P. Pavia A. 《Kinetics and Catalysis》2002,43(4):453-458
The kinetics of reactions of acrylamide derivatives (acrylamidotrihydroxymethylmethane (TA), sodium 4-acrylamidobutanoate (AA3), sodium 6-acrylamidohexanoate (AA5), and sodium 11-acrylamido-undecanoate (AA10)) with piperidine and morpholine in water (for TA, also in DMF, DMSO, and formamide) is studied at 293 K. These compounds are weak surfactant monomers. The critical concentrations of micelle formation (CCM) for them are determined. The self-association of AA3, AA5, and AA10 producing micelles results in a decrease in their reactivity compared to the monomeric forms. The rates of the reactions of surfactant monomers (SM) with morpholine and piperidine are described by the second-order rate law w
0 = k[SM]0[Amine]0. An empirical equation is derived that relates the CCM values to the rate constant for the reaction of a surfactant monomer with a secondary amine with charges on the -carbon and oxygen atoms of the amide group of a surfactant monomer. The rates of the reactions of TA with piperidine and morpholine are determined by the electrophilicity (acidity) of the medium, which is favorable for the Michael reaction. 相似文献
3.
Simonyan G. S. Beileryan N. M. Pirumyan E. G. Roque J.-P. Boyer B. 《Kinetics and Catalysis》2001,42(4):474-478
The kinetics of reactions between ,-unsaturated compounds (UCs) (acrylonitrile (AN), acryl-amide (AA), and methacrylamide (MAA)) and secondary amines (As) (piperidine, morpholine, diethanolamine, diethylamine, and dipropylamine) in water, as well as in DMF, DMSO, formamide, and 1,4-dioxane for acrylonitrile, was studied. It was found that w= k[HC]0[A]0for all of the test pairs. Viscosity, permittivity, and solvation characteristics, such as solvent polarity, nucleophilicity, and electrophilicity, were taken into account in considering the solvent effect on the overall reaction rate. The electrophilicity (acidity) of a medium was found to exert the greatest effect on the reaction rate. It is believed that an increase in the electrophilicity is favorable for the rapid protonation of the UC–amine intermediate complex. The effects of amine basicity, ionization potential, and dipole moment and the steric parameters of substituents in amine molecules on the rates of reactions between the unsaturated compounds and secondary amines were considered. 相似文献
4.
Conclusions The reaction of perfluoroketones with alkylvinyl ethers leads to 2-alkoxy-4,4-bis(perfluoroalkyl) oxethanes, subsequent isomerization of which yielded-alkoxyvinyl-bis(perfluoroalkyl)carbinols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 918–921, April, 1967. 相似文献
5.
Kazheva O. N. Aleksandrov G. G. D'yachenko O. A. Chernov'yants M. S. Simonyan S. S. Lykova E. O. 《Russian Journal of Coordination Chemistry》2004,30(10):739-746
Complex formation in systems containing 3-carboxypropyltriphenylphosphonium or tetraphenylphosphonium bromide, molecular iodine, and chloroform solution was compared. The maximum number of iodine molecules coordinated by bromides in the solution was established by spectrophotometric method using a function of average iodine number and the stability constants of the complexes were determined. The diiodobromide [(C6H5)4P]BrI2 was studied by X-ray diffraction analysis. The ab initio calculations were performed for [Y(R)4]I3 (Y = N, P, As; R = CH3, C6H5). The obtained experimental data and the correlations with the results of quantum-chemical calculations revealed that the tetraphenylphosphonium cation binds diiodobromide anions through the terminal halogen atoms with equal probability. 相似文献
6.
In the oxidation of propylene a sharp change in the concentration of radicals, observed when passing from the slow reaction region to cool flames, indicates the chain character of the cool flame. Unlike propane and butane, the temperature dependence of the radical concentration and the maximum self-heating are practically unchanged within 603–663 K.
. , . , 603–663 , .相似文献
7.
8.
9.
10.