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排序方式: 共有349条查询结果,搜索用时 31 毫秒
61.
G. V. Yukhnevich E. G. Tarakanova A. V. Kepman I. V. Bykovc 《Russian Chemical Bulletin》2008,57(9):1867-1873
IR spectra and densities of solutions in a binary liquid system (BLS) HF-Et2O were measured for the first time for the molar ratios of the components ranging from 1: 12 to 14: 1 and 31: 1, respectively.
An analysis of the concentration dependences of the normalized (to the total number of moles of the BLS components in 1 L)
absorbance and excess density of the studied solutions revealed that they contained heteroassociates with stoichiometric ratios
of the molecules of 1: 2, 2: 1, 4: 1, and 11–12: 1. The concentration range in which each associate is formed in the binary
mixture HF-Et2O was estimated for all the associates. The results obtained were compared with the data on the HF: Solv ratios (Solv is solvent)
in molecular complexes that prevail in the seven BLS HF-organic solvent studied earlier.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1833–1839, September, 2008. 相似文献
62.
V. A. Mamedov S. V. Vdovina E. I. Vorkunova L. V. Mustakimova A. F. Saifina A. T. Gubaidullin I. Kh. Rizvanov Ya. A. Levin I. A. Litvinov 《Russian Chemical Bulletin》2008,57(6):1257-1263
Condensation of diethyl isophthaloyldiacetate, aromatic aldehyde, and urea in the presence of Me3SiCl proceeds efficiently and faster than in the absence of the latter to form 1,3-bis(2-oxo-1,2,3,4-tetrahydropyrimidin-6-yl)benzene
derivatives capable to give inclusion complexes with DMF.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1233–1239, June, 2008. 相似文献
63.
研究了三氟化硼乙醚(BF3·OEt2)催化2-(N-取代氨基甲酰基甲基氨基)苯甲醇与醛的反应,发展了合成取代3,1-苯并噁嗪类化合物的方法,通过该方法合成了一系列新型结构的1-(氨基甲酰基甲基)-2-烃基-3,1-苯并噁嗪类化合物。 对于这类反应BF3·OEt2比三甲基氯硅烷(TMSCl)和四氯化锡(SnCl4)的普适性更广,它能有效催化这类反应,而后二者却不能。 探讨了TMSCl和SnCl4不能催化2-(N-取代氨基甲酰甲基氨基)苯甲醇与醛反应的原因。 相似文献
64.
用5ns,1064nm的脉冲Nd:YAG激光,研究了乙醚团簇与纳秒激光的相互作用.在1011 W/cm2量级光强下,观察到价电子完全剥离的O6+,C4+,且这些高价离子的强度比值基本不随激光能量而变化.用阻滞电压方法测量了电离过程中溢出电子能量分布,在最大激光能量4.0×1011 W/cm2,溢出电子的平均能量为56eV,最大能量为102eV.实验结果支持了高价离子产生的“多
关键词:
高价离子
电子能量
纳秒激光
乙醚团簇 相似文献
65.
一氧化碳偶联制草酸二乙酯用Pd-Fe/α-Al2O3催化剂的表面结构 总被引:3,自引:0,他引:3
应用XPS,XRD,TEM和TPR等表征技术研究了CO常压气相偶联合成草酸酯反应体系中Pd-Fe/α-Al2O3催化剂的表面结构. 结果表明,催化剂表面的活性组分钯以高度分散的Pd0形式存在,分散的钯微晶平均粒径约为8 nm; 助剂铁以Fe2+形式存在,其分散度极高. 根据表征实验结果,讨论了活性组分、助剂和载体三者之间的相互作用. 助剂可以优先高度分散在载体表面,而活性组分会自动落位在助剂层上达到均匀分散,即催化剂表面形成了类似于金属-金属氧化物-载体相间的结构. 相似文献
66.
Direct anodic oxidation of 1,5-dihydroxynaphthalene (DHN), an important derivative of naphthalene, led to the formation of high-quality semiconducting poly(1,5-dihydroxynaphthalene) (PDHN) on stainless steel sheets in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of DHN in this medium was measured to be only 0.78 V vs. SCE, which was lower than that determined in traditional acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (0.98 V vs. SCE). As-formed PDHN films showed good redox activity and stability, together with interesting electrochromic property from brown (doped) to yellow-green (dedoped). Structural characterization, including FTIR, 1H NMR, and quantum chemistry calculations, indicated that the polymerization of DHN probably occurred at C4 and C8 positions. Moreover, thermal analysis revealed that PDHN displayed better thermal stability than that synthesized by chemical method. The fluorescence spectral studies, together with the electrical tests, showed that PDHN was a good blue light-emitter (fluorescence quantum yield higher than 0.1) with an electrical conductivity of as high as 0.46 S/cm. 相似文献
67.
High-quality poly(fluorene-9-acetic acid) (PFAA), a new soluble polyfluorene derivative, was synthesized electrochemically by direct anodic oxidation of fluorene-9-acetic acid (FAA) in boron trifluoride diethyl etherate (BFEE) containing a certain amount of trifluoroacetic acid (TFA). This electrolyte enables facile anodic oxidation of FAA monomer at lower potential (1.05 V vs. SCE). PFAA films with conductivity of 0.53 S cm−1 obtained from this medium showed better redox activity and thermal stability in relation to unsoluble poly(fluorene-9-carboxylic acid). Fluorescent spectral studies indicate that PFAA film with high fluorescence quantum yields and photochemical stability is a good blue-light emitter. The structure and morphology of the polymer were studied by UV–vis, FT-IR, 1H NMR spectra and scanning electron microscopy, respectively. 相似文献
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