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1.
Thermal decomposition of model alkylcyclohexane mixtures with different ratios of components has been investigated. The possibility to estimate the yield of reaction products by calculating the relative activities of a group of hydrocarbons is shown.
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2.
M.P. Saksena 《Chemical physics letters》1974,27(3):448-450
A semi-empirical method is developed for the prediction of the thermal conductivity of binary liquid mixtures. The proposed method is tested by calculating the thermal conductivity of twelve binary liquid mixtures and an excellent agreement between the observed and calculated values is obtained. 相似文献
3.
L. Sulacsik 《Journal of Thermal Analysis and Calorimetry》1974,6(1-2):215-220
A two-component pyrotechnical mixture containing MnO2 and Pb3O4 has been investigated by TG, DTG and DTA. It was found that under 48 % MnO2 content the oxygen release exceeds the value calculated on the basis of the reactions MnO2 → Mn3O4 and Pb3O4 → PbO. Above a MnO2 content of 7.5 % the decomposition is partly delayed and shifted to higher temperatures. With under 60% of MnO2, at about 700? the components react exothermally with an increase in weight. The combined heats of the reactions MnO2 → Mn2O3 and Pb3O4 → PbO give the highest value at 83 % of MnO2. 相似文献
4.
The thermal behaviours of barium ortho-, meta- and para-nitrobenzoates were studied by DTA, TG and Emanation Thermal Analysis (ETA) in the temperature range 20 – 300°. The application of ETA as a supplement to the classical thermoanalytical methods (DTA and TG) for the study of organic compounds in the solid state is demonstrated.Absolute values of emanating power, measured at room temperature for samples quenched from temperatures before and after the effects in the thermoanalytical curves, provide valuable characteristics of the intermediate products of thermal treatment, especially with regard to the degree of disorder of the molecular structure. The evolution of the molecular structure of each isomer during heating is discussed, and new X-ray patterns of the different compounds are given.
The authors are obliged to Dr. M. V. Mathieu and Ing. C. Quet, Institute for Catalysis Researches, Villeurbanne, France, for valuable discussion of the I.R. spectra and for assistance in the experimental work, respectively. 相似文献
Zusammenfassung Das thermische Verhalten von Ortho-, Meta- und Para-Isomerem des Bariumnitrobenzoats wurde durch DTA, TG und Emanations-Thermoanalyse (ETA) im Temperaturbereich von 20–300°C untersucht. Die Anwendung der ETA als Ergänzung klassischer thermoanalytischer Verfahren (DTA und TG) zum Studium organischer Verbindungen wird beschrieben.Die absoluten Werte der Emanationskraft, gemessen an Mustern, welche von Temperaturen vor und nach den Effekten abgekühlt worden waren, werden an Hand thermoanalytischer Kurven gezeigt. Sie stellen wertvolle Charakteristika von Zwischenprodukten der thermischen Behandlung dar, besonders hinsichtlich des zerstörten Ordnungsgrades der Molekularstruktur. Die Entwicklung der Molekularstruktur jedes Isomers während der Aufheizung wird erörtert und neue Röntgenspektra der verschiedenen Verbindungen werden angeführt.
Résumé Par TG, ATD et ATE on a étudié, dans le domaine compris entre 20 et 300°C, le comportement thermique des nitrobenzoates de baryum (isomères ortho, méta et para) et on a montré l'intérêt de l'ATE utilisée comme technique complémentaire de la TG et de l'ATD pour l'étude de composés organiques à l'état solide.En mesurant, pour chaque composé, les valeurs absolues du pouvoir émanateur avant et après chaque effet endothermique ou exothermique, on a pu mettre en évidence les caractéristiques des produits intermédiaires qui apparaissent au cours du traitement thermique, notamment en ce qui concerne le degré de désordre de la structure moléculaire. On a discuté l'évolution de cette structure pour chaque isomère au cours du chauffage. Les diagrammes de diffraction X présentés sont tous nouveaux.
-, - - 20–300° , (). . , , . , . .
The authors are obliged to Dr. M. V. Mathieu and Ing. C. Quet, Institute for Catalysis Researches, Villeurbanne, France, for valuable discussion of the I.R. spectra and for assistance in the experimental work, respectively. 相似文献
5.
The characteristics of the evolution of the flame inhibitors HCl and metal chlorides from thermally degrading mixtures of a chloroparaffin and antimony trioxide or Bi compounds are compared with reference to the behaviour of these mixtures as fire retardant additives for polymers. 相似文献
6.
L. Sulacsik 《Journal of Thermal Analysis and Calorimetry》1973,5(1):33-42
The author investigated a two-component pyrotechnical mixture used in the manufacture of delay detonators. Comparing the thermogravimetric, derivative thermogravimetric and differential thermal analysis curves of components with that of mixtures containing the components in different ratios, a relation has been found between the reaction rate and ratio. Initial temperature of reaction can be defined as well. Release of oxygen and oxidation takes place separately at certain temperatures and ratios. Mixture of highest rate of reaction generates the lowest heat of reaction. 相似文献
7.
Adriana Fuliaş Titus Vlase Gabriela Vlase Nicolae Doca 《Journal of Thermal Analysis and Calorimetry》2010,99(3):987-992
The thermoanalytical curves (TA), i.e. TG, DTG and DTA for pure cephalexin and its mixtures with talc, magnesium stearate,
starch and microcrystalline cellulose, respectively, were drawn up in air and nitrogen at a heating rate of 10 °C min−1. The thermal degradation was discussed on the basis of EGA data obtained for a heating rate of 20 °C min−1. Until 250 °C, the TA curves are similar for all mixtures, up this some peculiarities depending on the additive appears.
These certify that between the pure cephalosporin and the excipients do not exists any interaction until 250 °C. A kinetic
analysis was performed using the TG/DTG data in air for the first step of cephalexin decomposition at four heating rates:
5, 7, 10 and 12 °C min−1. The data processing strategy was based on a differential method (Friedman), an integral method (Flynn–Wall–Ozawa) and a
nonparametric kinetic method (NPK). This last one allowed an intrinsic separation of the temperature, respective conversion
dependence on the reaction rate and less speculative discussions on the kinetic model. All there methods had furnished very
near values of the activation energy, this being an argument for a single thermooxidative degradation at the beginning (192–200 °C). 相似文献
8.
A. Bubnov Věra Hamplová M. Kašpar Anikó Vajda Maja Stojanović Dusanka Ž. Obadović N. Éber Katalin Fodor-Csorba 《Journal of Thermal Analysis and Calorimetry》2007,90(2):431-441
Two series of binary mixtures composed of bent shaped and rod like molecules are reported. The first star shaped bent core
molecules were synthesized and used as a component of binary mixtures. The chiral rod like compounds having commensurable
length with the arms of the bent core compounds have been chosen for these mixtures. The resulted compositions show various
thermotropic liquid crystalline phases that are characteristic to both types of liquid crystalline materials. In case of mixing
the rod like molecules to the bent core compound the B2, B7 and induced B1 phases have been observed. While using the star-shaped
bent core and chiral rod like compounds in mixture, the paraelectric smectic A, ferroelectric smectic C* and orthogonal hexatic
smectic B phases were preferred. The appearing mesophases were investigated by differential scanning calorimetry, polarizing
optical microscopy and X-ray diffraction methods. 相似文献
9.
Differential scanning calorimetry (DSC) has been employed to study the thermal denaturation processes of the main protein
fractions of blood serum. These processes have been compared for albumins (nondefatted (HSA) and fatty acid free (HSAf)),
α,β-globulins, γ-globulins, and their mixtures in aqueous (pH 6.5) and buffer (pH 7.2) solutions. The results have indicated
that α,β-globulins inhibit γ-globulins’ aggregation in buffer solutions. The decrease of stability of HSA and HSAf aqueous
solutions has been observed in the presence of γ-globulins. The mixtures of albumins and γ-globulins have revealed the tendency
to ready aggregation in water. Moreover, the results have suggested that neither γ-globulins nor albumins severely change
the stability of α,β-globulins. 相似文献
10.
Fátima Duarte Freire Cícero Flávio Soares Aragão Túlio Flávio Accioly de Lima e Moura Fernanda Nervo Raffin 《Journal of Thermal Analysis and Calorimetry》2009,97(1):333-336
Rifampicin–Isoniazid mixture is a frequently used product in the treatment of tuberculosis. Rifampicin exhibits polymorphism
and exists in two polymorphic forms: the stable form I and the metastable form II. The aim of this work was to evaluate the
thermal behavior of the binary mixtures of polymorphs I and II of rifampicin and isoniazid by using DSC. Mixtures of different
forms (rifampicin form I and II) showed interaction with isoniazid indicating that the mixtures are less stable compared to
the drug alone. Interaction was observed in case of both polymorphs of rifampicin. 相似文献
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12.
J. Lu X. -J. Wang Y. -X. Liu C. -B. Ching 《Journal of Thermal Analysis and Calorimetry》2007,89(3):913-919
The effect of excipients on the secondary structure of lyophilized proteins was studied through second-derivative Fourier
transform infrared (FTIR) spectroscopic analysis. The glass transition temperature (T
g), denaturation temperature (T
d) and moisture content were determined by differential scanning calorimetry (DSC) and thermogravimetry (TG). T
g, T
d and the preservation of protein secondary structure were found to be dependent upon the type and amount of the excipient
included in the formulation. Meanwhile, the lyophilized proteins easily adsorbed amounts of moisture during storage to reduce
their T
gs and stability. 相似文献
13.
A. Miyake A. Kimura T. Ogawa Y. Satoh M. Inano 《Journal of Thermal Analysis and Calorimetry》2005,80(2):515-518
Summary In order to obtain a better understanding of the thermal hazard of hydrazine and nitric acid mixtures which are used in PUREX (Plutonium and Uranium Recovery by Extraction) process during recycling of spent fuel in nuclear plant, DSC and small scale reaction calorimetry super-CRC were carried out for the mixtures in various conditions. From the DSC analysis the apparent activation energy of hydrazine monohydrate in SUS 303 crucible was determined to be 96 kJ mol-1. The mixing hazard of hydrazine monohydrate with nitric acid was measured with super-CRC and the results suggested that the concentration and the mass of nitric acid had a strong influence on the mixing heat of reaction of the system. 相似文献
14.
Rotich M. K. Brown M. E. Glass B. D. 《Journal of Thermal Analysis and Calorimetry》2003,73(2):687-706
The thermal behaviour of the aminosalicylic acids is compared with the behaviour of their 1:1 molar ratio physical and kneaded
mixtures with each of three different cyclodextrins (b-, hydroxypropyl-b-, and g-cyclodextrin), using differential scanning
calorimetry and thermogravimetry coupled with evolved gas analysis by Fourier transform infrared spectroscopy. X-ray powder
diffraction and infrared spectroscopy provided complementary information. Comparison of the effects of the different cyclodextrins
on the behaviour of the individual aminosalicylic acid isomers shows that hydroxypropyl-b-cyclodextrin has the greatest interaction
with 3-aminosalicylic acid and 5-aminosalicylic acid, followed by g-cyclodextrin, while b-cyclodextrin generally shows the
least interaction. For 4-aminosalicylic acid, the effect of g-cyclodextrin seems to be more marked than for 3-aminosalicylic
acid and 5-aminosalicylic acid.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Matsunaga Hiroki Katoh Katsumi Habu Hiroto Noda Masaru Miyake Atsumi 《Journal of Thermal Analysis and Calorimetry》2019,135(5):2677-2685
Journal of Thermal Analysis and Calorimetry - This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate... 相似文献
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17.
When polypropylene is thermally degraded in mixtures with a highly chlorinated fire retardant chloroparaffin, a smaller amount of the lighter hydrocarbon fraction, which is also modified in composition, is evolved compared with that evolved from pure polypropylene. A corresponding increase in the amount of high boiling chain fragments is obtained from the mixtures. This effect can be explained in terms of the interactions which occur between degrading polymer and additive. 相似文献
18.
In mixtures of polystyrene with a fire retardant chloroparaffin, the rate of volatilisation of the polymer is initially increased during the thermal dehydrochlorination of the additive. In the residue which results, the volatilisation of polystyrene occurs at a lower rate than when it is heated alone. The mechanisms of the reactions which occur in the mixture are discussed and related to the fire retardant action of the chloroparaffin. 相似文献
19.
The thermal characteristics of mixtures of cyclonite (RDX) and nitroglycerine (NG) and of RDX and diazidonitrazapentane (DIANP) were studied. The thermal decomposition processes of NG and RDX are not synchronous with those of RDX/NG mixtures. The DSC curves show two obviously exothermic peaks, one at 203°C for NG and other at 240°C for RDX. However, there is only a single exothermic peak in the DSC curves of RDX/DIANP mixtures within certain ratio limits, due to the coincidence of the exothermic decomposition peaks for both RDX and DIANP and their mutual dissolution. The effects of the different thermal characteristics of different explosives on the combustion performance are also discussed. 相似文献
20.
Lorenzo Abate Ignazio Blanco Gianluca Cicala Antonino Recca Carmelo Luca Restuccia 《Polymer Degradation and Stability》2006,91(12):3230-3236
The thermal and rheological characterizations of seven random, low molecular weight (Mn ≅ 9500 g mol−1), H2N-ended polyethersulfone/polyetherethersulfone (PES/PEES) copolymers, at various PES/PEES ratios, were performed. The glass transition temperatures (Tg) were determined by DSC. Degradations were carried out in a thermobalance, under flowing nitrogen, in dynamic heating conditions from 35 °C to 650 °C. The initial decomposition temperatures (Ti) and the half decomposition temperatures (T1/2) were directly determined by TG curves, while the apparent activation energies of degradation (Ea) were obtained by the Kissinger method. In addition, the complex viscosities (η∗) of the molten polymers were determined in experimental conditions of linear viscoelasticity. Tg, Ea and η∗ values increased linearly with PES% content, while Ti and T1/2 values showed opposite behaviour. In every case both PES and PEES homopolymers felt outside linearity. The results obtained are discussed and interpreted, and compared with those of corresponding Cl-ended copolymers previously studied. 相似文献