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1.
A deNOx catalyst was prepared by wash-coating a cobalt ion exchanged ZSM-5 zeolite together with an alumina binder on a cordierite
honeycomb structure. A few types of the Co-ZSM-5 based catalysts were tested for NOx reduction with C2H4 under oxidizing conditions in the temperature range between 250–600°C. Preliminary tests of the catalytic activity of the
systems showed NOx reduction up to 95% at temperatures between 400–550°C using a mixture of a synthetic gas and air as reactant. 相似文献
2.
A. M. Aliev U. A. Mamedova Kh. R. Samedov A. A. Sarydzhanov R. Yu. Agaeva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(2):288-292
ZSM-5 high-silica zeolite was obtained from metakaolinite, Dzhenranchel’sk volcanic ash, and silica gel at T = 150–220°C, pH 9–13, and τ = 48–240 h with the use of an organic structure-forming additive, butanediol-1,4, in an alkaline
solution. Optimum conditions for the synthesis of ZSM-5 zeolite were found (T = 200°C, pH 10, τ = 144 h). The catalytic properties of its H-form in vapor-phase esterification of acetic acid (I) with ethanol (II) were studied at 140–180°C and a I: II molar ratio from 1 to 2. Synthesized HZSM-5 showed high activity and selectivity in this reaction. 相似文献
3.
A. Atbir L. Aneflous A. Marrouche M. El Hadek R. Cohen-Adad M.-Th. Cohen-Adad 《Journal of Thermal Analysis and Calorimetry》2000,59(3):893-900
Polytherm diagram of the ternary system KCl–FeCl2 –H2 O between 0 and 70°C. Phase equilibria in the KCl–FeCl2 –H2 O system were studied over the temperature range 0–70°C by conductimetric and analytical methods.
A solubility polytherm of the system was constructed. We have observed the crystallization fields of the KCl and FeCl2 6H2 O (at 0°C), KCl and FeCl2 4H2 O (at 15, 30 and 40°C) and KCl, FeCl2 4H2 O and of a double salt KClFeCl2 2H2 O are obtained at 70°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
D. I. Mirzai T. M. Guliev V. N. Akhmedov A. A. Isirikyan 《Russian Chemical Bulletin》1998,47(2):352-354
The ammonium form of natural zeolite, natrolite, obtained by vapor phase ion exchange is similar to calcium-containing zeolites
of the natrolite group in its de- and rehydration characteristics and the heats of immersion in water. The adsorption capacity
and the heat of immersion in water are maximum after evacuation of the zeolite at 200 °C. The irreversible sintering of NH4 natrolite occurs above 200 °C (up to 45% at 500 °C), accompanied by the formation of hydroxyl groups.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 359–361, February, 1998. 相似文献
5.
Elżbieta Godlewska M. Mitoraj F. Devred B. E. Nieuwenhuys 《Journal of Thermal Analysis and Calorimetry》2007,88(1):225-230
A Ti–45.9Al–8Nb
(at%) alloy with a lamellar structure (γ+α2)
was oxidised in air at 700, 800, 850 and 900°C in isothermal and thermal
cycling conditions. The reaction progress was followed by thermogravimetric
measurements. In isothermal conditions the oxidation kinetics followed approximately
a parabolic rate law and the rate constants ranged from about 10–12
kg2 m–4 s–1
at 700°C to 10–10 kg2
m–4 s–1
at 900°C. The oxide scales were built of Al2O3
and TiO2, the former being the main component of the
outermost layer. The oxidation behaviour of Ti–45.9Al–8Nb was
referred to a commercial titanium alloy, WT4 (Ti–6Al–1Mn), and
selected oxidation-resistant alloys. 相似文献
6.
K. De Buysser I. Van Driessche J. Schaubroeck S. Hoste 《Journal of Sol-Gel Science and Technology》2008,46(2):133-136
A novel sol–gel synthetic route using water-soluble precursor salts is presented as a synthetic path for a high-purity negative
thermal expansion material, ZrW2O8. This synthetic route involves a sol–gel method with the use of EDTA as complexing agent. The aqueous solution is transformed
into a ceramic material after a two-step heat treatment: gelation at 60 °C and reactive sintering at 1,180 °C. The decomposition
of the gel is monitored with infrared spectroscopy and TGA. The high-temperature heat treatment results in ZrW2O8 with its characteristic negative thermal expansion behaviour α[75–130 °C]: −9.8 ± 1.6 μm/m °C and α[175–300 °C]: −1.2 ± 0.2 μm/m °C. 相似文献
7.
S. Yamaguchi 《Colloid and polymer science》1998,276(12):1151-1158
The change of three-phase behavior of a water/hexaethylene-glycol dodecyl ether (C12EO6)/propanol/heptane system was studied with increasing temperature (30.0–48.9 °C). A cone-like three-phase body consisting
of aqueous (W), surfactant (Dp), and oil (O) phases is formed in the composition tetrahedron at lower temperatures. The body is expanded with increasing
temperature, and touches the water–C12EO6–heptane triangle (the base) at 44.8 °C. At about 45.6 °C the loci of the Dp and O phases meet and cut off at a critical double end point and the three-phase body separates into two bodies: one has
a chiral shape and the other is unclosed. The unclosed body is transformed with the change of shape of the tie triangle on
the base as temperature increases and leaves from the base at 48.9 °C. A closed-loop miscibility gap between middle surfactant
(D′
p) and O phases or a cone-like three-phase body is formed inside the composition tetrahedron at higher temperatures. The roles
of C12EO6 and propanol are also discussed.
Received: 14 April 1998 Accepted: 15 July 1998 相似文献
8.
A. I. Boltalin E. E. Knyazeva E. A. Zhilinskaya D. Courcot A. Aboukais B. V. Romanovsky 《Russian Chemical Bulletin》2000,49(8):1365-1368
Thermal destruction of the binuclear monofluoroacetate complex Cu2(CH2FCOO)4 deposited on zeolite Y was studied by the TG-DTA and ESR methods. Large particles of copper oxide are not formed and fine
dispersion of CuO in the matrix is observed due to low temperatures of the destruction of the supported complex (240–250°C)
and restriction of the process mainly to large cavities of the zeolite.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1371–1374, August, 2000. 相似文献
9.
Wu Yan Jia Qingzhu Wang Bingwen Zheng Wei Yi Shouzhi 《Russian Chemical Bulletin》2010,59(9):1686-1691
The influence of a thin spreading solvent film (ethanol, diethyl ether, and three fractions of petroleum ether boiling at
30–60 °C, 60–90 °C, and 90–120 °C) on the properties of hexadecan-1-ol (C16H33OH) monolayers at the air—water interface was studied. The specific evaporation resistance and the surface pressure were determined
to describe the spreading behavior of the C16H33OH monolayers. The physical properties of the solvents and the images obtained in an atomic force microscope were examined.
The time of establishing the equilibrium spreading surface pressure of monolayers can be reduced using a more volatile solvent
with a lower boiling point and a lower relative density. The influence of the monolayer nature on water evaporation corresponds
to the order of changing the solvent spreading rate: petroleum ether (30–60 °C) > diethyl ether > ethanol > petroleum ether
(60–90 °C) > petroleum ether (90–120 °C). The monolayers formed upon petroleum ether (30–60 °C) spreading form a film with
a less deficient and relatively planar surface. When ethanol is used as a spreading solvent, water evaporation is accelerated
rather than retarded, while petroleum ether (30–60 °C) is more appropriate for this purpose. 相似文献
10.
Electrical conductivity in the monoclinic Li2TiO3, cubic Li1.33Ti1.67O4, and in their mixture has been studied by impedance spectroscopy in the temperature range 20–730 °C. Li2TiO3 shows low lithium ion conductivity, σ300≈10–6 S/cm at 300 °C, whereas Li1.33Ti1.67O4 has 3×10–8 at 20 °C and 3×10–4 S/cm at 300 °C. Structural properties are used to discuss the observed conductivity features. The conductivity dependences
on temperature in the coordinates of 1000/T versus loge(σT) are not linear, as the conductivity mechanism changes. Extrinsic and intrinsic conductivity regions are observed. The change
in the conductivity mechanism in Li2TiO3 at around 500–600 °C is observed and considered as an effect of the first-order phase transition, not reported before. Formation
of solid solutions of Li2–
x
Ti1+
x
O3 above 900 °C significantly increases the conductivity. Irradiation by high-energy (5 MeV) electrons causes defects and the
conductivity in Li2TiO3 increases exponentially. A dose of 144 MGy yields an increase in conductivity of about 100 times at room temperature.
Electronic Publication 相似文献
11.
Maria Luisa A. Gon?alves Joyce R. C. Barreto Wildson V. Cerqueira Ana Maria R. F. Teixeira 《Journal of Thermal Analysis and Calorimetry》2009,97(2):515-519
This work evaluates the effect of the FCC catalyst components—Y zeolite, kaolin and alumina—on the formation of coke during
the cracking of heavy residue (HR) of petroleum. The Y zeolite, kaolin and alumina were mixed with a HR at a ratio of approximately
1:4. The effect was studied using dynamic thermogravimetry at a heating rate of 50 K min−1, with N2 (between 35 and 700 °C) and air (in the 700–1,000 °C temperature range). The HR analyzed in these conditions formed 8.1%
of coke. All the mixtures presented larger coke formation than that observed in pure HR. The Y zeolite presented fourfold
larger coke formation, while kaolin and alumina showed twofold higher formation than pure HR. The major focus of this study
was to verify the sensitivity of the TG technique in providing information about coke formation in the fluid catalytic process
of refineries. 相似文献
12.
T. Kaljuvee M. Radin D. Astahhov Y. Pelovski 《Journal of Thermal Analysis and Calorimetry》2006,84(1):59-66
Coupled
TG-FTIR technique was used for identification of gaseous compounds evolved
at thermal treatment of six coal samples from different deposits (Bulgaria,
Russia, Ukraine). The experiments were carried out under dynamic heating conditions
up to 900°C at heating rates of 5, 10 or 50 K min–1
in a stream of dry air. The emission of CO2, H2O,
CO, SO2, COS, methane, methanol, formic acid, formaldehyde,
acetaldehyde, chlorobenzene was clearly identified in FTIR spectra of the
samples studied. The formation of ethanol, ethane, ethylene and p-xylene, at least on the level of traces, was also
identified. At the heating rate of 5°C min–1
the temperature of maximum intensities of the characteristic peaks of COS
was 270°C, of formaldehyde, formic acid, ethane and methanol 330°C,
of SO2, CO, acetic acid, ethylene and p-xylene
400°C and of chlorobenzene 500°C. At 10°C min–1
and 50°C min–1 these temperatures were
shifted, respectively, by 70–300°C and 150–450°C towards
higher temperatures and the respective absorption bands in FTIR spectra were,
as a rule, more intensive. 相似文献
13.
Masuda Y. Seto Y. Wang X. Tuchiya Y. 《Journal of Thermal Analysis and Calorimetry》2001,64(3):1045-1051
The thermal dehydration of La[Co(CN)6]⋅5H2O proceeded through at least three stages from the temperature range of30~230°C, and an abrupt mass loss occurred around 350°C
and the perovskite type oxide,LaCoO3 was obtained at 1000°C.
After dehydration, the color of the anhydride changed from white to pale blue around 230°C and furthermore, the color changed
to blue around 290°C. These color changes were discussed on the basis of the changes of coordination structures around Co
ions.
In La[Co(CN)6]⋅5H2O, Co3+ ions lie at the center of the Oh crystal field consisted of six CN– ions. However, in the pale blue specimen, Co3+ ions were situated in the center of D4h crystal field which was distorted the Oh one by lengthening of the trans CN– ions along z-axis. In the blue specimen, Co3+ ions were reduced to Co2+ ions which were situated in the Td crystal field formed by four CN–ions as [Co(CN)4]2–.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
1. Results of thermodynamic and kinetic investigations for the different crystalline calcium carbonate phases and their phase
transition data are reported and summarized (vaterite: V; aragonite: A; calcite: C). A→C: T
tr=455±10°C, Δtr
H=403±8 J mol–1 at T
tr, V→C: T
tr=320–460°C, depending on the way of preparation,Δtr
H=–3.2±0.1 kJ mol–1 at T
tr,Δtr
H=–3.4±0.9 kJ mol–1 at 40°C, S
V
Θ= 93.6±0.5 J (K mol)–1, A→C: E
A=370±10 kJ mol–1; XRD only, V→C: E
A=250±10 kJ mol–1; thermally activated, iso- and non-isothermal, XRD
2. Preliminary results on the preparation and investigation of inhibitor-free non-crystalline calcium carbonate (NCC) are
presented. NCC→C: T
tr=276±10°C,Δtr
H=–15.0±3 kJ mol–1 at T
tr, T
tr – transition temperature, Δtr
H – transition enthalpy, S
Θ – standard entropy, E
A – activation energy.
3. Biologically formed internal shell of Sepia officinalis seems to be composed of ca 96% aragonite and 4% non-crystalline calcium carbonate.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
H-ZSM-5 (Si/Al = 10.6 and 20) efficiently catalyzes the transformation of ethanol into C5-C12 gasoline hydrocarbons in 27–33 mass % yield at 320°C and feed rate 20 mmol C2H5OH/(gcat·h). Only ethylene is produced on the mesoporous zeolite H-ZSM-5/Al-MCM-41 with 100% ethanol conversion. This discrepancy
may be attributed to blockage of the ZSM-5 micropores in the mesoporous zeolite structure. 相似文献
16.
A. V. Davidov S. S. Travnikov B. F. Myasoedov 《Journal of Radioanalytical and Nuclear Chemistry》1973,14(2):285-293
The possibility has been investigated of separating rare-earth fission fragment elements from106Ru and137Cs by high-temperature sublimation (950°C) of chlorides, with their subsequent gas adsorption separation in a quartz tube
under a temperature gradient in a flow of the carrier-gas Ar+SOCl2. The temperature corresponding to the maxima of the element precipitation zones are: 630–660°C (144Ce), 770–780°C (0.7–6 μg140La+La), 920°C (1.5 mg Ce or La), 420–450°C (106Ru), 280–300°C (137Cs). The coefficients of element separation have been calculated. For the separation of indicator amounts of rare-earth elements
and106Ru and137Cs, fractional sublimation of the chlorides of the latter at 650°C has been used. Rate constants and effective activation
energies of the overall processes of chlorination-sublimation of the elements have been determined. 相似文献
17.
Klaartje De Buysser Philippe F. Smet Bart Schoofs Els Bruneel Dirk Poelman Serge Hoste Isabel Van Driessche 《Journal of Sol-Gel Science and Technology》2007,43(3):347-353
This paper describes the synthesis of ZrW2O8 by the use of an aqueous citrate-gel method in order to prepare a fine, pure and homogeneous oxide mixture suitable for ceramic
processing. The thermal expansion coefficient thus obtained for α-ZrW2O8 is −10.6 × 10−6 °C−1 (50–125 °C) whereas for the β-ZrW2O8 a value of −3.2 × 10−6 °C−1 (200–300 °C) is obtained. The advantages of the use of a sol–gel method is expressed in the very homogeneous end-products.
The paper describes crystallographic data, morphological structure and the thermal expansion properties of the ZrW2O8 material. Moreover, photoluminescence and photochromic properties specific to the precursor gel are described and analyzed.
These effects support our views that the precursors show homogeneity up to nanometer level. 相似文献
18.
A. S. Rozenberg E. I. Aleksandrova G. I. Dzhardimalieva A. N. Titkov A. D. Pomogailo 《Russian Chemical Bulletin》1993,42(10):1666-1672
The thermal decomposition of iron (III) acrylate, [Fe3O(CH2=CHCOO)6 · 3H2O]OH (FeAcr), a monomer with a complex cluster cation, has been studied at 200–370 °C. Thermal transformations of FeAcr occur
in two temperature regions. The rates of gas evolution in the low temperature region (200–300 °C) and the high temperature
region (300–370 °C) are described by first-order equations withk=4.2 · 1021exp[−59000/(RT)] s−1 andk=1.3 · 106exp[−30500/(RT)] s−1, respectively. A study of the qualitative and quantitative composition of the products of FeAcr thermolysis was carried out.
The thermal transformation of FeAcr is a complex process of dehydration, degradation, and polymerization in the solid phase
followed by decarboxylation of the metal-carboxyl groups of the polymer.
for part 33 see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1743–1750, October, 1993. 相似文献
19.
A novel surfactant peptide consisting of an arginine cation with laurate anion has been synthesized, purified and characterized.
The critical micellar concentration (cmc) of peptide in aqueous solutions has been determined using spectroscopic techniques
and is found to increase from 0.06 to 0.11 mM with increasing temperature (15–45 °C). Cmc is also determined in the presence
of salts like NaCl, KCl and sodium acetate and it is found that these electrolytes hinder aggregation with a significant increase
in the case of sodium acetate. The aggregation number of the surfactant peptide has been determined using fluorescence quenching
measurements and is observed to decrease from 14 to 6 with increasing temperature (15–45 °C). The standard free energy change
(ΔG
0
m) and standard enthalpy change (ΔH
0
m) of the peptide aggregate are found to be negative with a small positive value for standard entropy change (ΔS
0
m). The peptide aggregate seems to undergo phase transition above 50 °C as observed from UV–vis and fluorescence spectroscopy.
From pyrene binding studies, it is shown that the interior dielectric constant increases from 5.08 at 34 °C to 8.77 at 50 °C
and further decreases with increase in temperature indicating a phase change at 50 °C. Also, the ratio of excimer intensity
to monomer intensity, which is a measure of microviscosity of the aggregate, decreases with increase in temperature with a
change at 50 °C indicating a phase change.
Received: 14 February 1997 Accepted: 13 August 1997 相似文献
20.
E. Matteoli L. Lepori T. R. Usacheva V. A. Sharnin 《Journal of Thermal Analysis and Calorimetry》2009,97(3):811-816
The influence of H2O–EtOH and H2O–Acetone mixed solvents at various compositions on the thermodynamics of complex formation reaction between crown ether 18-crown-6
(18C6) and glycine (Gly) was studied. The standard thermodynamic parameters of the complex [Gly18C6] (log K°, Δr
H°, Δr
S°) were calculated from thermochemical data at 298.15 K obtained by titration calorimetry. The complex stability and its formation
enthalpy increase with increasing the non aqueous component concentration in both mixed solvents. The thermodynamic data were
discussed on the basis of the solvation thermodynamic approach and the solvation contributions of the reagents and of the
complex to the complex stability were analyzed. 相似文献