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1.
A. I. Prokof'ev N. A. Malysheva N. N. Bubnov S. P. Solodovnikov M. I. Kabachnik 《Russian Chemical Bulletin》1976,25(3):494-497
| 1. | A method is proposed for investigating fast reactions of aroxyl radicals. The kinetic parameters obtained for the reaction of 2,4,6-tri-t-butylphenoxyl with phenol and with 4-bromophenol coincide with the data obtained by other methods. |
| 2. | From an analysis of the kinetic data, it is concluded that the OH bond energy in 4-methyl-2,6-di-t-butylphenol is close to that in 2,4,6-tri-t-butylphenol. |
2.
| 1. | The kinetics of the Cannizzaro reaction of benzaldehyde in aqueous KOH solution have been studied spectrophotometrically, working at 25°C and at concentrations ranging from 19.1 to 37.9%. |
| 2. | Reaction proceeds through the formation of an activated complex consisting of the doubly ionized and the un-ionized forms of benzaldehyde and the hydroxide cation. |
| 3. | The spectrophotometric data and the kinetic data have been combined to give an estimate of the benzaldehyde ionization constant in aqueous KOH solution at 25°C. |
| 4. | Analysis of the kinetic data for benzaldehyde reduction by formaldehyde has shown the activated complex for this reaction to be composed of an un-ionized benzaldehyde molecule and a doubly ionized formaldehyde molecule, with or without participation of the hydroxide cation. |
3.
| 1. | Potentiometric titration in nitromethane at 25°C has been used to determine dissociation constants for 16 mono-substituted benzoic acids. |
| 2. | Brönsted and Hammett equations have been set up for the compound series under study here. |
| 3. | The data of the literature have been used to evaluate the nitromethane autoprotolysis constant, pKS24. |
| 4. | The relative differentiating action of nitromethane with respect to other solvents has been evaluated from the slopes of the Brönsted and Hammett plots and the values of the autoprotolysis constant. The differentiating action of nitromethane with respect to acids is greater than that of acids with respect to alcohols and acetone, but less than that of DMSO, acetonitrile, and DMF. |
| 5. | Study has been made of the dissociation of the aminobenzoic acids in nitromethane. Solutions of p-aminobenzoic acid are free of zwitterions, while solutions of the m-aminobenzoic acid contain these ions to the extent of 50%. |
4.
N. V. Zakatova D. R. Minkhadzhidinova M. A. Nadzhafova R. F. D'yachkovskaya N. P. Koaovalova V. A. Sharpatyi 《Russian Chemical Bulletin》1976,25(2):434-436
| 1. | We determined the reactivity of some nitrogen bases, and of a number of amino acids and bis-(diazoacetyl)alkyl derivatives toward the electron at 77°K. |
| 2. | The effect of the pH at 77°K as established on the yield of the deamination process and the reactivity of the studied amino acids toward the electron. |
| 3. | It was found that the yield for the deamination of glutamic acid is increased in the presence of inositol (acceptor of OH radicals). |
5.
R. G. Kostyanovskii V. P. Leshchinskaya R. K. Alekperov G. K. Kadorkina L. L. Shustova Yu. I. Él'natanov G. L. Gromova A. É. Aliev I. I. Chervin 《Russian Chemical Bulletin》1988,37(11):2315-2323
| 1. | An efficient method of aziridine dimer synthesis is presented involving reaction of aziridine with esters of strong organic acids followed by alkaline hydrolysis of the resultant N-acyl derivatives. |
| 2. | New N-acyl and carbamoyl derivatives of aziridine dimer and trimer were synthesized. |
| 3. | Linear and branched isomers of aziridine tetramer and also diastereomers of 2-methylaziridine dimer were isolated and characterized. |
| 4. | An efficient regiospecific synthesis of 2,2-dimethylaziridine dimer and trimer was developed. |
6.
Presently, a large variety of layered materials are synthesized that are able to intercalate neutral guest molecules or to exchange inorganic and organic ions for interlayer ions. Several of these materials are also found as minerals.The intracrystalline reactivity of a few selected compounds will be described and compared to clay minerals:
相似文献
| – | - intercalation into crystalline silicic acids; |
| – | - reactions of phosphates, arsenates, and sulfates; |
| – | - reactions of titanates, niobates, and molybdates with long chain alkylammonium ions, and |
| – | - anion exchange properties of double hydroxides. |
7.
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. |
8.
A. D. Shebaldova V. I. Mar'in M. L. Khidekel' I. V. Kalechits S. N. Kurskov 《Russian Chemical Bulletin》1976,25(11):2335-2338
| 1. | By polymerizing various monomers in the presence of transition-metal salts (e.g., WCl6) and a Grignard reagent, disproportionation catalysts containing a carbochain polymeric support have been obtained. Lewis acids were used as cocatalysts for the disproportionation of the olefins. |
| 2. | The activity and selectivity in the action of the catalytic systems obtained have been studied as a function of the nature of the cocatalyst, the ratio of the components, and the nature of the solvent in the disproportionation of 2-pentene. |
9.
| 1. | The dependence of the rate of decomposition in aqueous solutions of dialkyl substituted nitrosoureas based on monoquaternary alkylammonium salts on pH conforms to the ElcB mechanism of decomposition. |
| 2. | A new compound of the chloroethylnitrosourea class has been discovered. Its rate of decomposition in neutral and weakly alkaline media is independent of pH. |
10.
| 1. | The strong bathochromic shift of the absorption bands of aminoazo compounds in acid medium is due to the formation of a cation of quinoid structure. |
| 2. | Aminoazo compounds are weak NH acids in aprotic polar solvents, and they form the corresponding mesomeric anions in the presence of alkalis. |
| 3. | The synthesized aminoazo compounds are very weak NH acids, and electron-donor substituents weaken the acid properties of the amino group, while electron-acceptor substituents intensify them. |
11.
| 1. | The existence of synergism is demonstrated; the activity of Pd-Tc/carrier catalysts in the dehydrogenation of hydrocarbons considerably exceeds that of monometallic catalysts. The most active catalysts are those with PdTc ratios from 11 to 23. |
| 2. | In terms of reactivity on Pd-Tc catalysts, the hydrocarbons are arranged as follows: cyclohexene > cyclohexane > methylcyclohexane > ethylcyclohexane > n-hexane. |
| 3. | Activity in the dehydrogenation of cyclohexane varies as follows: Pd-Tc/-Al2O3 > Pd-Tc/MgO > Pd-Tc/TiO2 > Pd-Tc/Y2O3 > Pd-Tc/SiO2. |
| 4. | A decrease in CO chemisorptive capacity on bimetallic catalysts compared to monometallic catalysts is established. |
12.
B. L. Korsunskii G. V. Sitonina B. S. Fedorov F. I. Dubovitskii L. T. Eremenko 《Russian Chemical Bulletin》1989,38(4):710-713
| 1. | The thermal decomposition of N,N-dinitroamines is homogeneous and unimolecular in the gas phase. The limiting step of the process is the rupture of the N-NO2 bond. |
| 2. | The activation parameters of the process imply that the dinitroamine group is more reactive than the mononitroamine group in thermal decomposition. The energy of dissociation of the N-NO2 bond in dinitroamines is 42 kJ/mole less than in mononitroamines. |
| 3. | Nitrogen dioxide and acetaldehyde do not influence the kinetics of thermal decomposition of dinitroamines due to their high reactivity. |
13.
A. S. Vzdykhan'ko V. V. Glushenko M. N. Mirzayanova A. Ya. Khorlin 《Russian Chemical Bulletin》1976,25(3):689-691
| 1. | 2-O-p-Nitrophenyl-N-acetyl--neuraminoside, a suitable substrate for the kinetic study of neuraminidases, was synthesized, and its stability was studied. |
| 2. | The sodium salt of this ketoside is stable during prolonged storage. |
14.
| 1. | Thermodesorption measurements have shown the surface of aluminum-nickel-tungsten sulfide catalysts to be nonuniform with respect to cyclohexane, the nonuniformity being characterized by an exponential distribution, a step adsorption isotherm, and a logarithmic fall off of the desorption activation energy with increasing surface coverage. |
| 2. | The degree of cyclohexane coverage of the catalyst surface is increased by the presence of hydrogen, and the energy of adsorptional bonding is reduced. |
| 3. | Cyclohexane bonds to the catalyst surface more weakly than does benzene, and can be completely displaced from the surface by the latter. |
15.
In conclusion, let us note the principal results of the calculation.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 35–41, March-April, 1992. 相似文献
| 1. | On a clean Ni(100) surface, only molecular adsorption of water is realized. Partial dissociation of H2O is thermodynamically allowed process; however, dissociation of water is impossible because of kinetic limitations. |
| 2. | Modification of the nickel surface by oxygen stabilizes the donor-acceptor pair (H2O/O) on the surface and removes the kinetic limitation in decomposition of water, through a substantial reduction of the activation energy of dissociation. |
| 3. | The promoting role of oxygen is manifested in an increase in the nonuniformity of electron density on the nickel surface in the vicinity of the [Ni]–OH2 bond, which makes it possible to open up a new channel of the reaction in which a high degree of energy compensation in the water dissociation reaction is possible. |
16.
Azatyan V. V. Borodulin R. R. Markevich E. A. Rubtsov N. M. Semenov N. N. 《Russian Chemical Bulletin》1976,25(7):1396-1397
| 1. | Flames resulting from chain NCl3 decomposition are propagated through NCl3 + He mixtures lying outside the autoignition region. |
| 2. | The fact that these are essentially isothermal flames is an indication of the important role of positive chain interaction in this process. |
17.
| 1. | A general method of synthesis of azomethine compounds of boron has been proposed from imines and esters of thioboric acids. The reaction between ketimines and diesters of thioboroorganic acids led to the formation of diiminoboranes. Triiminoboranes were obtained on interacting ketimines and thioborates. |
| 2. | Diiminoboranes and triiminoboranes obtained from alkylarylketimines exist as mixtures of imines and enamines. |
18.
K. K. Kalnin'sh 《Russian Chemical Bulletin》1988,37(9):1768-1773
| 1. | A new method of analysis of autocatalytic reactions was developed which permits determining the rate constants of noncatalytic and catalytic reaction pathways with the data from one kinetic curve. |
| 2. | The reverse reaction of acylation has an autocatalytic character. |
| 3. | In comparison to CHCl3, in CH3CN, all of the rate constants increase by 2–4 times, and the noncatalytic reaction pathways are more sensitive to the nature of the solvent. |
19.
| 1. | A practicable method for the synthesis of vicinal bis(difluoramino)-containing carboxylic acids by reacting tetrafluorohydrazine with unsaturated acids has been developed. |
| 2. | ,-Bis(difluoramino)carboxylic acids are unstable and undergo decarboxylation followed by dehydrofluorination. |
| 3. | ,-Bis(difluoramino)carboxylic acids are fairly stable and in some cases display the properties of ordinary carboxylic acids. |
20.
| 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. |