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1.
B. A. Nabiev L. I. Lafer V. I. Yakerson A. M. Rubinshtein 《Russian Chemical Bulletin》1976,25(7):1398-1402
| 1. | CO2 interacts with the hydrogen forms of type Y zeolites, erionite, and mordenite without experiencing any loss in symmetry. |
| 2. | The adsorption of CO2 at 20°C on zeolites containing monovalent cations involves ion-dipole cation interaction in the case of A, X, and Y zeolites, erionite, and mordenite, and the formation of more stable carbonate structures in the case of the A, X, and Y zeolites. Transition between the bidentate coordinated carbonate structure and the carbonate ion proceeds through adsorbed forms of CO2 resulting from ion-dipole interactions. |
| 3. | The symmetry of stable carbonate structures established on the Ca forms of zeolites A, X, and Y can alter under the action of various adsorbates. |
2.
| 1. | Using seven independent methods it was found that the concentration of the active centers on the surface of-Al2O3, which are responsible for the dehydration, is (9±1)×1017 centers/m2. The catalytically active centers are identical with adsorption centers. |
| 2. | A method of calculating the stochiometry, concentration, and thermodynamics of the surface association reactions has been developed. |
| 3. | The first reaction step proceeds according to the associative bimolecular substitution mechanism, with the formation of an associative intermediate compound. The association enthalpy and entropy have been calculated. |
3.
| 1. | The crystal conformation and geometrical parameters have been determined for 7-oxa-[10]--cyclothiene-1,6-dione. |
| 2. | The atoms of the thiophene ring and the adjacent group are not coplanar. The conformation of the theonyl fragment is O,s-cisoidal; the C=O dipoles are essentially antiparallel, one with respect to the other. |
4.
Ethylene-olefin copolymers differ from other polyethylenes in that:
With the help of a cross-fractionation method we interpreted the differences of the experimental data, according to the molecular mass fractionation and the branching received. 相似文献
| - | there is no long chain branching; |
| - | short chain branching is determined by the comonomer unit; |
| - | the molecular mass distribution is sharp; |
| - | the side chain distribution on different molecules is broad; |
| - | the sequential distribution of branching is very broad along the molecular chains, which becauses a multi-peak lamella distribution, and a multi-peak melting heat. |
5.
| 1. | An increase in the SiO2/Al2O3 ratio (x) in type Y zeolites through dealuminization with ethylenediaminetetraacetic acid leads to an increase in their catalytic activity during the alkylation of benzene with ethylene. |
| 2. | The properties of CaNaY zeolites of the same composition prepared from NaY obtained by hydrothermal synthesis and by dealuminization of samples with a small value of x are identical. |
| 3. | Carbon dioxide exerts an accelerating effect on the Ca forms of dealuminized type Y zeolites of various compositions and has no effect on the properties of NaY'. |
6.
L. A. Rozov Yu. V. Zeifman N. P. Gambaryan Yu. A. Cheburkov I. L. Knunyants 《Russian Chemical Bulletin》1976,25(12):2560-2566
| 1. | Depending on the nature of the substituent in the 2 position, l-fluoro-l-(-hydrohexafluoroisopropyl)ethylenes are dehydrofluorinated to either allenes or 1,3-dienes. |
| 2. | It was shown that allylic substitution is possible in the reactions of perfluoroisobutylene with carbanions; the mutual transformations of the allyl and vinyl isomers were studied. |
| 3. | The perfluoroalkenylation product was obtained when perfluoroisobutylene is reacted with ketene acetal. |
7.
É. D. Filippova N. D. Mitrofanova L. I. Martynenko V. I. Spitsyn 《Russian Chemical Bulletin》1976,25(1):4-7
| 1. | Complexes of the REE, Y, and Sc with hydroxyethylethylenediaminetriacetic acid have been isolated in solid form. The hydrate compositions of the complexes have been determined. |
| 2. | The La and Pr complexes form hydrates of different compositions. The LnL hydrates form slightly nonisostructural groups in the series La-Lu. |
| 3. | According to thermographic analysis data, the hydrate water in the LnL·nH2O complexes of different hydrate compositions is not bonded with the same firmness. |
8.
| 1. | The N-chloro-N-nitroamides of arylsulfonic acids react with olefins to give a mixture of the N- and O--chloroalkylation products of the nitroamides. |
| 2. | When arylsulfonic acid N-chloro-N-nitroamides react with monosubstituted ethylene derivatives the nitroamide group adds to the least hydrogenated carbon atom of the multiple bond. |
9.
| 1. | We synthesized some new iminoxyl biradicals that contain bis(azamethine), bis(azamethine)-octatriene, bis(azamethine)phenylene, bis(azamethine)thiophene, and bis(azamethine)dithienyl sulfide bridges. |
| 2. | Intramolecular spin -spin exchange in iminoxyl biradicals can be accomplished via the bis(azamethine)octatriene, bis(azamethine)-1,4-phenylene, and bis(azamethine)-2,5-thiophene systems. |
| 3. | The degree of overlapping of the orbitals of the unpaired electrons in the new biradicals was estimated. |
10.
L. F. Chertanova G. A. Marchenko A. A. Gazikasheva Yu. T. Struchkov V. F. Sopin L. N. Punegova A. S. Mukhametzyanov 《Russian Chemical Bulletin》1989,38(2):250-253
| 1. | The planar alkoxydiazinoxide fragments are shown to have the Z-configuration and be orthogonal to each other by an x-ray structure study of a series of alkoxydiazinoxides. |
| 2. | In the oxydiazinoxide fragments, p- conjugation occurs. |
| 3. | The molecules of the compounds in the crystals studied are joined by hydrogen bonds. |
11.
A. M. Moiseenkov V. A. Dragan A. V. Lozanova V. V. Veselovskii 《Russian Chemical Bulletin》1988,37(8):1603-1609
| 1. | Dimethyl, diphenyl, and tetramethylene sulfoxide hydrochlorides react with methylheptenyl, citronellyl, and geranyl acetates to give predominantly the allylic chlorination products. |
| 2. | These findings are preferably to be regarded as involving AdE reactions between the weakly electrophlic hydroxy and (or) chlorosulfonium cation and the trisubstituted C=C bond in these olefins at the key stage. |
| 3. | The addition of lithium perchlorate has been found to accelerate this reaction. |
| 4. | Sulfoxide hydrobromides are highly selective brominating agents for the terminal grouping in isopropenoid oligoolefins. |
12.
F. M. Stoyanovich G. B. Chermanova Ya. L. Gol'dfarb R. G. Karpenko 《Russian Chemical Bulletin》1976,25(7):1503-1508
| 1. | p-Bis(tert-butylsulfonyl)benzene (I) and 2,5-bis(tert-butylsulfonyl)thiophene (II) when treated with n-BuLi are capable of replacing one of the sulfonyl groups by the n-butyl group. |
| 2. | The conditions were found where sulfone (II) is metalated in the position of the thiophene ring. |
| 3. | Lithium 2-thienyimercaptide is metalated in the free position. |
13.
| 1. | A series of C-functional derivatives of (3)-1,2-dicarbaundecaborate was synthesized and some of their properties were studied. |
| 2. | Apparent ionization constants of acids of the (3)-1,2-dicarbaundecaborate series were measured and it was found that they are very weak carboxylic acids. |
| 3. | Upon reaction with excess LiA1H4, under mild conditions the carbonyl, *20c \CH(OH) / \begin{array}{*{20}c} \backslash \\ {CH(OH)} \\ / \\ \end{array} , and CH2OH groups of dicarbaundecaborate ketones and alcohols are reduced to CH2 and CH3 groups, respectively. |
| 4. | The effect of Grignard reagent on ketones and esters of the dicarbaundecarbprate series was studied and it was established that the composition of reaction products depends both on the steric hindrance of the carbonyl group and on the electron-donating effect of the (3)-1,2-dicarbaundecaborate substituent. |
14.
The reactivity of partially purified alkaline protease fromBacillus subtilis, to keratin and collagen containing substances has been investigated. The experimentally obtained apparent values of the
Michaelis-Menten constant (Km), the maximum reaction rate (Kmax, and the energy of activation (Ea), lead to the conclusion that:
The relationship of Kmax was a function of temperature, aiming at the industrial application of this reaction, has been obtained. 相似文献
| 1. | The keratin containing substrates are not so easily digested as those containing collagen. |
| 2. | The kinetics of the reaction with time has been investigated. |
15.
T. E. Kron V. S. Lopatina L. N. Morozova S. A. Lebedev L. S. Isaeva D. N. Kravtsov é. S. Petrov 《Russian Chemical Bulletin》1989,38(4):703-707
| 1. | The complexes ArNiXL2 and HNiXL2 (X is halide, L is tertiary phosphine) in the presence of zinc catalyze the condensation of bromobenzene with styrene (stilbene formation). |
| 2. | The yield of stilbene and 1,3-diphenylbutene, the dimerization product of styrene, in the presence of pyridine is lowered according to the substitution of phenyl groups on the phosphorus ligand L by alkyl (ethyl, cyclohexyl) groups. |
| 3. | Change of triphenylphosphine to phenylethylphosphines and tricyclohexylphosphine in the hydride complex HNi(X)(PR3)2, the catalytic activity of which falls in the order X=Cl–Br–>I–, favors the dimerization of styrene in the absence of pyridine. |
16.
Jacques Satgé 《Chemistry of Heterocyclic Compounds》1999,35(9):1013-1032
Germylenes, divalent germanium species, and germanium derivatives with Ge=Y double bonds (Y=C=, O, S, N-, P-) are powerful synthetic reagents in organometallic chemistry. The germylenes exhibit properties analogous to those of carbenes and have been shown to insert into various -bonds such as carbon-heteroelement, metal-carbon, and metal-heteroelement of heterocyclic derivatives with ring expansion. The addition of germylenes to various unsaturated compounds (dienes, orthoquinones, carbonyl compounds, imines, nitrosobenzene) leads, as a rule, to cycloadducts with low stability except for dienes and quinones. The doubly bonded germanium species are highly reactive and widely used in organometallic synthesis in various types of reactions such as:
The mechanism and stereochemistry of some reactions are discussed.In commemoriation of 100 years of Academician A. N. Nesmeyanov birth.Université Paul Sabatier Toulouse, France. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1155–1175, September, 1999. 相似文献
| – | - addition (or insertion reactions) to various -bonds of organometallic compounds; |
| – | - insertion reactions with ring expansion of small organic rings; |
| – | - cycloaddition reactions with 1–2, 1–3, and 1–4 dipolar reagents. |
17.
| 1. | Study has been made of the kinetics of the-elimination of alcohol from 3-carbethoxy-4-ethoxy-2-pentanone in benzene and under the catalytic action of acetic acid. |
| 2. | This reaction involves formation of a complex between substrate and acetic acid. |
| 3. | The equilibrium constant for the reaction of forming the complex between substrate and acetic acid, and the rate constant for complex formation, have both been determined. |
18.
Lagerge S. Kamyshny A. Magdassi S. Partyka S. 《Journal of Thermal Analysis and Calorimetry》2003,71(1):291-310
A new batch titration microcalorimeter has been used for estimation of thermodynamic properties in various investigated colloidal systems. As examples, we present enthalpic and kinetic data obtained from this calorimetric device for four different processes widely encountered in colloid science:
This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
| (i) | The dilution/micellization process of cationic gemini surfactants in aqueous solution. |
| (ii) | The hydration process of non ionic surfactants in organic solution, i.e. the mechanism of micellar solubilization of water in the aggregates. |
| (iii) | The complexation of calcium ions by polyacrylates sodium salts (PaNa). |
| (iv) | The adsorption phenomenon of PaNa molecules on the calcium carbonate surface. |
19.
Vol'pin M. E. Savitskii A. V. Novodarova G. N. Kolosova E. M. 《Russian Chemical Bulletin》1976,25(7):1430-1434
| 1. | The chelate cobalt complex Co(II)N, N-bis(salicylidene)ethylenediamine [Co(Salen)] is an effective catalyst for NAD-H oxidation in methanol at room temperature. |
| 2. | The rate of oxidation is closely dependent on the structure of the complex catalyst and the composition of the solvent. |
| 3. | The mechanism of Co(Salen) complex catalytic activity in NAD-H autooxidation is discussed in terms of three proposed reaction schemes. |
20.
V. I. Sokol V. V. Davidov M. A. Porai-Koshits B. E. Zaitsev M. V. Palishkin G. V. Sheban V. I. Pakhomov S. S. Kukalenko 《Russian Chemical Bulletin》1988,37(6):1148-1153
| 1. | The crystal and molecular structures of N-(2-benzimidazolyl)-O-methyl carbamate and N-(2-benzimidazolyl)-O-ethyl carbamate have been determined. It was found that these compounds exist in the form of their tautomers (Ic) and (IIc). The spectroscopic characteristics (IR, EAS, and x-ray electronic spectrum) of N-(2-benzimidazolyl)-O-methyl carbamate were refined; these should prove beneficial in establishing the structures of metal complexes and salts of the indicated compounds. |
| 2. | It was also established that upon heating a solution of N-(2-benzimidazolyl)-O-methyl carbamate in ethanol in the presence of MnCl2-4H2O transesterification takes place to form N-(2-benzimidazolyl)-O-ethyl carbamate. |