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81.
82.
Double Salts Formation in the Systems MX–MeX 2–H2O (M=K,NH4, Rb,Cs; Me=Mg,Mn, Fe,Co, Ni,Cu; X=Cl,Br)
Balarew Christo Tepavitcharova Stefka 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):721-734
Monatshefte für Chemie - Chemical Monthly - ?The data available on the solubility phase diagrams and on the crystallization of chloride and bromide double salts in the systems... 相似文献
83.
The solubility diagram of the system NaAl(SO4)2–CsAl(SO4)2–H2O was investigated at 25°C. This is a system in which -and -alums participate. The fields of cristallization are outlined. There is one wide field of cesium aluminium alum and one, very narrow, of sodium aluminium alum. The eutonic point of the system lies at the composition of the liquid phase corresponding to 27.90 wt.% NaAl(SO4)2 and 0.008 wt.% CsAl(SO4)2. It was found that mixed crystals are not formed in the system. The solid phases were investigated by X-ray diffraction andDTA. 相似文献
84.
A block copolymer of propylene oxide (PO) and ethoxyethyl glycidyl ether (EEGE), (PO)(2)(EEGE)(6)(PO)(2), that has been found to possess lower critical solution temperature properties in water in the temperature range below 20 degrees C was mixed at 1:0.1, 1:1, and 1:10 weight ratios with commercially available Pluronic (L64 or P85) block copolymers. The cooperative association of the copolymers in aqueous solution was studied by dynamic light scattering over a wide temperature range (5-60 degrees C). At lower temperatures, the systems containing either L64 or P85 behave similarly irrespective of the composition: three species corresponding to (PO)(2)(EEGE)(6)(PO)(2) unimers, Pluronic-dominated mixed micelles, and large (50-60 nm in radius) composite (PO)(2)(EEGE)(6)(PO)(2)/Pluronic aggregates were identified. At a certain temperature, which is composition-dependent, the systems phase-separate [(PO)(2)(EEGE)(6)(PO)(2)/L64 1:0.1], enter an interval of instability [(PO)(2)(EEGE)(6)(PO)(2)/L64 1:1 and 1:10], or rearrange by dissociation of the large composite particles [(PO)(2)(EEGE)(6)(PO)(2)/P85]. The presence of a Pluronic micellar peak in the relaxation time distribution at lower temperatures, the dimensions of the composite particles, and the different behavior of the systems at elevated temperatures are discussed. A possible application of the thermosensitive mixtures in delivery/release of active substances is suggested. 相似文献
85.
Kirby AJ Dutta-Roy N da Silva D Goodman JM Lima MF Roussev CD Nome F 《Journal of the American Chemical Society》2005,127(19):7033-7040
Phosphate transfer from the 8-dimethylammonium-naphthyl-1-phosphate monoanion 4m to water and to a range of nucleophiles shows general acid catalysis by the neighboring NH(+) group, through the strong intramolecular hydrogen bond. Reactivity is insensitive to the charge on the nucleophile, so that fluoride and oxyanions displace dimethylaminonaphthol from the PO3(2-) group as effectively as do amines of the same basicity. Reactivity is (predictably) relatively insensitive to the basicity of the nucleophile and to the alpha-effect. A strong intramolecular hydrogen bond is present in the product, but also in the reactant, as evidenced by major perturbations in the pK(a)'s of the phosphate and dimethylamino groups, to 3.94 and 9.31, respectively, and by ab initio calculations. Rate accelerations are of the order of 10(6)-fold despite this stabilization: the strength of the hydrogen bond is evidently significantly enhanced in the transition state. The evidence suggests that it also depends remarkably strongly on the degree of ionization of the reacting phosphate group and will be significantly reduced for the neutral PO(OH)2 group. Thus, the hydrolysis of the substrate cation 4+ shows a correspondingly greater, >10(8)-fold acceleration. 相似文献
86.
Kostadinka Popandova-Yambolieva Christo Ivanov 《Monatshefte für Chemie / Chemical Monthly》1979,110(6):1467-1470
Reaction of the nitrile of 3,3-diphenyl-2-propenic acid with -branched nitriles in the presence of lithium amide in liquid ammonia does not give the correspondingMichael adducts but the ,-unsaturated nitriles6. Conc. sulfuric acid transforms these nitriles into the -lactones7.
Reaktion von 3,3-Diphenyl-2-propensäurenitril mit den Carbanionen einiger -verzweigter Nitrile (Kurze Mitteilung)
Zusammenfassung Die Reaktion von 3,3-Diphenyl-2-propensäurenitril mit -verzweigten Nitrilen in Gegenwart von Lithiumamid in flüssigem Ammoniak führt nicht zu den entsprechendenMichael-Addukten, sondern zu den ,-ungesättigten Nitrilen6. Durch Einwirkung von konz. Schwefelsäure entstehen aus diesen Nitrilen die -Lactone7.相似文献
87.
Dicyclopentadienyl- and diindenyl-calcium and their complexes with twofold coordinated ammonia and tetrahydrofuran are obtained by metalation of cyclopentadiene or indene with calcium or calcium amide in liquid ammonia and subsequent treatment with tetrahydrofuran and heat. IR and 1H NMR spectroscopy are used for structure elucidation. The reactivity of the complexes both in alkylation and in interaction with carbonyl compounds is studied. In this manner alkyl, hydroxyalkyl and alkylidene derivatives of cyclopentadiene and indene axe obtained. 相似文献
88.
The Chemical Transport of Sb2S3 With I2 The chemical transport of Sb2S3 with iodine is discussed on thermodynamical basis under consideration of the gaseous molecules I2, I1, SbI3, S2, S3, S4, S5, S6, S7 and S8. The experiments are in a satisfying agreement with the calculations. 相似文献
89.
Tanya Tsoncheva Daniela Paneva Ivan Mitov Holger Huwe Michael Fr?ba Momtchil Dimitrov Christo Minchev 《Reaction Kinetics and Catalysis Letters》2004,83(2):299-305
Iron modified silica and carbon mesoporous materials with similar textural characteristics are compared in methanol decomposition
to H2, CO and CH4. The influence of the support on the phase composition and reductive properties of the catalysts is studied by M?ssbauer
spectroscopy and TPR with hydrogen.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献