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1.
1.  The surface of a SnO2-Sb2O4 catalyst is uniformly homogeneous with respect to the heats of adsorption of isobutylene. The heats vary from 50 to 20 kcal/mole as the degree of coverage is increased to 18% of a monolayer.
2.  Isobutylene is adsorbed on SnO2-Sb2O4 in two forms: reversible (desorbed in the range 79–100° with Edes=21 kcal/mole) and irreversible.
3.  Irreversibly chemisorbed isobutylene exists on the surface primarily in the form of the-methallyl complex.
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2.
1.  Stilbite and heulandite begin to undergo sintering upon heating in vacuum at 200 ± 5°C and undergo about 80% dehydration.
2.  The rehydration energy (heat of immersion in water) of stilbite and heulandite reach maximal values of 350 ± 15 and 215 ± 15 J/g after pumping at 230 ± 20 and 200 ± 20°C, respectively. Maximum half-width values are reached at 250 and 300°C, respectively.
3.  The maximal integral mean-molar heats of adsorption of water vapor on stilbite and heulandite after pumping at 230 and 200°C, respectively, are 76 ± 3 and 69 ± 3 kJ/mole.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2855–2857, December, 1988.  相似文献   

3.
1.  The adsorption properties with respect to benzene vapors and the pore structure of carbon adsorbents with almost maximum development of the microporosity were studied.
2.  The position of the micropore volume distribution curves whose maxima correspond to a size (halfwidth) of 1.2–1.4 nm and micropore volumes 1.5 cm3/g is a characteristic feature of the adsorbents studied. The difference between ordinary active carbons and the active carbons investigated is only quantitative in the values of the parameters of the Dubinin-Stockley adsorption equation.
3.  The adsorption isotherms are described by the adsorption equation from the theory of volume filling of micropores in a wide range of equilibrium relative pressures and temperatures of 293–353 K with totally satisfactory precision.
4.  The question of the upper limit of the micropores of carbon adsorbents is discussed.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 977–983, May, 1988.  相似文献   

4.
1.  In NaA zeolite a homocharge is formed by charges deposited on the surface of the zeolite from the gas gap between the electrode and the specimen.
2.  The existence of thermoelectret effects has been found in the systems NaA-zeolite -air, NaA-helium, NaA-nitrogen, and NaA-oxygen.
3.  The thermoelectret effects are caused by both the accumulation of charges in the specimen and the adsorption of molecules in the electric field.
4.  A low mobility has been noted for adsorbed molecules in the electret state of the system.
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5.
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:
(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.
This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

6.
1.  The relation of the adsorption values of standard benzene vapor at 293 K to the parameters of the Dubinin-Stokley adsorption equation was considered for the case of model microporous carbon adsorbents.
2.  Active carbons with low characteristic standard-vapor adsorption energies and a wide micropore-volume size distribution are characterized by higher filling of the micropore volume at low equilibrium pressures in comparison with active carbons with homogeneous microporous structure.
3.  Fillings were calculated for micropores under various adsorption conditions for estimation of the adsorption properties of active carbons and selection of adsorbents with parameters most suitable for practical use.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 506–509, March, 1989.  相似文献   

7.
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.
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8.
1.  The absorption of electromagnetic radiation ( 1.05 mm) by solutions of DMSO in water and DMSO and water in dioxane has been measured in the whole interval of relative concentrations.
2.  The additivity of the absorption in systems containing dioxane, and its absence in the system H2O-DMSO, have been demonstrated.
3.  The possibility of using the absorption of radiation in the millimeter range for the study of solvation in solutions has been shown.
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9.
1.  N-Ethyl and N-isopropyl-3-piperidones were synthesized and the stereochemistry of their reduction was studied.
2.  The dependenceof stereochemistryof a series of reactions at the carbonyl center on bulk of the substituent on nitrogen was established.
3.  Pure a- and e-epimers of N-ethyl- and N-isopropyl-3-piperidols were separated.
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10.
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.
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11.
1.  Nitroxyl biradicals of the triazine, N,N-bis(triazinyl)ethylenediamine, N,N-bis(triazinyl)piperazine, and s-nitropyrimidine series have been prepared.
2.  The ESR spectra of liquid and frozen solutions of these biradicals have been obtained and N. - O group separations calculated.
3.  Toluene solutions of (II), (V), (VI), and (X) biradicals contain at least four different conformations, each with its own value of the exchange integral.
4.  In one of the biradical (V) conformations, spin interaction exchange is through the chain of atoms linking the N.-O fragments.
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12.
The energy metabolism of a mammalian cell line grown in vitro was analyzed by substrate consumption rates and metabolic flux measurements. The data allowed the determination of the relative importance of the pathways of glucose and glutamine metabolism to the energy requirements of the cell. Changes in the substrate concentrations during culture contributed to the changing catalytic activities of key enzymes, which were determined.
1.  A murine B-lymphocyte hybridoma (PQXB1/2) was grown in batch culture to a maximum cell density of 1–2×106 cells/mL in 3–4 d. The intracellular protein content showed a maximum value during the exponential growth phase of 0.55 mg/106 cells. Glutamine was completely depleted, but glucose only partially depleted to 50% of its original concentration when the cells reached a stationary phase following exponential growth.
2.  The specific rates of glutamine and glucose utilization varied during culture and showed maximal values at the midexponential phase of 2.4-nmol/min/106 cells and 4.3 nmol/min/106 cells, respectively.
3.  A high proportion of glucose (96%) was metabolized by glycolysis, but only limited amounts by the pentose phosphate pathway (3.3%) and TCA cycle (0.21%).
4.  The maximum catalytic activity of hexolinase approximates to the measured flux of glycolysis and is suggested as a rate-limiting step. In the stationary phase, the hexokinase activity reduced to 11% of its original value and may explain the reduced glucose utilization at this stage.
5.  The maximal activities of two TCA cycle enzymes were well above the measured metabolic flux and are unlikely to pose regulatory barriers. However, the activity of pyruvate dehydrogenase was undetectable by spectrophotometric assay and explains the low level of flux of glycolytic metabolites into the TCA cycle.
6.  A significant proportion of the glutamine (36%) utilized by the cells was completely oxidized to CO2.
7.  The measured rate of glutamine transport into the cells approximated to the metabolic flux and is suggested as a rate-limiting step.
8.  Glutamine metabolism is likely to occur via glutaminase and amino transaminase, which have significantly higher activities than glutamate dehydrogenase.
9.  The calculated potential ATP production suggests that, overall, glutamine is the major contributor of cellular energy. However, at the midexponential phase, the energy contribution from the catabolism of the two substrates was finely balanced—glutamine (55%) and glucose (45%).
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13.
1.  Upon interaction of OH with Ni(100)m Ni(111), and Ni(110), stable, many-center forms of OH adsorption are produced. One-center and bridge forms of OH adsorption on nickel are kinetically unstable for the lowest surface coverages.
2.  On Ni(100) and Ni(111), a linear form of adsorption of OH is realized; on Ni(110), an angular form is realized, with a polar angle 0 = 20°.
3.  In the course of adsorption, there is a significant transfer of electron density from the metal to the OH, leading to an increase in the work function of the electrons and a decrease in the frequency of the (O–H) vibration. For the angular forms of adsorption, bending vibrations (O–H–Ni) are active.
4.  Upon adsorption of OH, a strong -bond Ni(110)–OH is formed, as manifested in the UV photoelectron spectra by absorption in the 9.2 eV energy region.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Institute of Kinetics and Catalysis, Bulgarian Academy of Sciences, Sofia. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 29–34, March–April, 1992.  相似文献   

14.
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.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 297–301, February, 1989.  相似文献   

15.
1.  The dipole moments of the two kinds of C-O bonds in acetals and their analogs are not identical.
2.  In formal molecules and the dimethylketal of acetone the C-O-C-O -C chains have gauche-gauche conformation, with the methyl groups lying on different sides of the O-C-O plane.
3.  The dimethylketal of tetrachlorocyclopentadienone is represented by a mixture of trans-gauche and gauche-gauche conformers.
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16.
1.  The condensation of 1,2-hydroxylamino oximes with biacetyl leads to 1-hydroxy-2-acetyl-2,4,5,5-tetrasubstituted 3-imidazoline 3-oxides.
2.  When 1-hydroxy-2-acetyl-2,5,5-trimethyl-4-phenyl-3-imidazoline 3-oxide is oxidized the CH3CO group is cleaved to give the 5H-imidazole 1,3-dioxide.
3.  Stable nitroxyl radicals were obtained when the 1-hydroxy-2-oximiaoethyl-2,4,5,5-tetrasubstituted 3-imidazoline 3-oxides are oxidized.
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17.
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.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2566–2575, November, 1988.  相似文献   

18.
1.  The molecular-sieve properties of a number of synthetic and natural chabazites have been investigated.
2.  Characteristic differences have been revealed in the molecular-sieve properties, thermal stability, and x-ray characteristics between the two groups of the zeolites studied.
3.  A reversal of the molecular-sieve effect on passing from the calcium to the sodium-calcium forms of certain synthetic and natural chabazites has been observed.
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19.
1.  It has been shown that 2-bromo-l,3,2-dioxaarsenanes exist in chair conformation with axially oriented As-Br bonds.
2.  Polarity and polarizability parameters have been found for the As-O and As-Br bonds in 2-bromo-l,3,2-dioxaarsenanes.
3.  The so-called -effect is stronger in the O2AsBr group than in the O2AsCl group.
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20.
1.  Following the CNDO/2 approximation to the SCF MO LCAO method, electronic parameters have been calculated for the molecules and ions of various nitro compounds.
2.  Calculated values of the dipole moment and enthalpy of atomization proved to be in satisfactory agreement with the experimentally determined values, the maximum deviation between them amounting to 1.4% for the aromatic systems.
3.  The nitro compound parameters most sensitive to change in the intramolecular interaction are the C-N bond energy and the charges on the carbon and halide atoms.
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