共查询到20条相似文献,搜索用时 31 毫秒
1.
Wei-Biao Ye Dong-Sheng Zhu Nan Wang 《Journal of Thermal Analysis and Calorimetry》2012,109(3):1487-1492
A free-base tetra sodium meso-tetra (p-sulphonatophenyl) porphyrin (TPPS4) and its corresponding metalloporphyrins (MTPPS4), where M?=?Co, Ni and Zn were synthesized and characterized by UV?Cvisible spectroscopy, infra red spectroscopy and 1H nmr spectroscopy. Thermal studies of these porphyrins were conducted in synthetic air from room temperature to 800?°C. The residues of MTPPS4 were qualitatively analyzed which showed the presence of corresponding metal oxides and Na2SO4. Further, the above porphyrins were subjected to TG-EGA-MS analysis in argon atmosphere to study the evolved gases/species during the thermal events. This information is useful to know the ring opening sequence of these porphyrins at corresponding temperatures. 相似文献
2.
Fabian Niedermair Roman Trattnig Kurt Mereiter Martin Schmuck Stefan Sax Emil J. W. List Christian Slugovc 《Monatshefte für Chemie / Chemical Monthly》2010,43(6):847-858
Abstract
Luminescent organoplatinum complexes featuring 8-quinolinolates as chelating ligands have been synthesized and characterized. Substitution of the quinolinolate ligand has been achieved in the 5 position, where benzoyl substituents were introduced by reacting 8-hydroxyquinoline and the corresponding benzoyl chloride in a Friedel–Crafts acylation. The resulting complexes, κ2(N,C2)-(2-(4-tert-butylphenyl)pyridine)-κ2(N,O)-(5-(4-tert-butylphenyl)(8-quinolinolato-5-yl)methanone)platinum(II) and κ2(N,C2)-(3-hexyloxy-2-phenylpyridine)-κ2(N,O)-((8-quinolinolato-5-yl)phenylmethanone)platinum(II), have been investigated by nuclear magnetic resonance and infrared spectroscopy, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, X-ray analysis, thermal analysis, cyclic voltammetry, UV–vis absorption spectroscopy, and luminescence measurements in solution and in the solid state. The solid-state structures of the complexes were found to be dominated by π–π intermolecular interactions. Organic light-emitting devices based on the complexes and a matching host material gave red to near-infrared electroluminescence with low-onset voltages (4–5 V) and continuous wave luminance intensities exceeding 500 cd/m2. 相似文献3.
Grzegorz Zi?ba Marcin Rojkiewicz Violetta Kozik Krystyna Jarzembek Anna Jarczyk Aleksander Sochanik Piotr Ku? 《Monatshefte für Chemie / Chemical Monthly》2012,58(4):153-159
Abstract
A series of mono-alkylcarboxylic acid derivatives of tetraphenylporphyrin have been prepared. All the porphyrins were completely characterized by use of mass, 1H NMR, UV–visible, and fluorescence spectroscopy. Experimental log P were determined by use of reversed-phase thin-layer chromatography with use of log P Rekker. These porphyrins are potential photosensitizers in photodynamic therapy. 相似文献4.
Giseli Aparecida Bernabé S. Almeida C. A. Ribeiro M. S. Crespi 《Journal of Thermal Analysis and Calorimetry》2011,106(3):773-778
The composting process using sugarcane bagasse, animal manure, and urea as source of organic matter, microorganism, and nitrogen,
respectively, were evaluated regarding the thermal behavior considering the maturation period: 0 (raw), 15, 22, 30, and 60 days.
Thermogravimetric and differential thermal analysis curves were obtained in a synthetic air atmosphere and heating rate of
10 °C min−1 in the range of 30–600 °C. The raw compost showed 80% organic matter, which was reduced up to 58% to 60 days compost. Two
main mass losses were verified, corresponding to characteristics exothermic peak in differential thermal analysis curves depending
on the maturation period. The variation in organic composition was evaluated by Fourier transform infrared spectroscopy verifying
the structures (lignin, cellulose, and hemicelluloses) changes with composting process, and the gas chromatography–mass spectrometry
was used to identify substance soluble in hexane. 相似文献
5.
Oana Ştefănescu Marcela Stoia Mircea Ştefănescu Titus Vlase 《Journal of Thermal Analysis and Calorimetry》2009,97(1):251-256
Hybrid organic–inorganic materials, silica–diol, were synthesized by the sol–gel process from mixtures of tetraethylorthosilicate
(TEOS) and diols: ethylene glycol (HO–CH2–CH2–OH) and 1,3 propane diol (HO–CH2–CH2–CH2–OH), in acid catalysis. The gels have been synthesized for a molar ratio H2O:TEOS = 4:1 and different molar ratios diol/TEOS: 0.25; 0.5; 0.75; 1.0; 1.25 and 1.5. The resulting gels were studied by
thermal analysis and FT-IR spectroscopy, in order to evidence the interaction of diols with silica matrix. Thermal analysis
indicated that the condensation degree increases with the molar ratio diol/TEOS until a certain value. The thermal decomposition
of the organic chains bonded within the silica network in the temperature range 250–320 °C, leaded to a silica matrix with
modified morphology. The adsorption–desorption isotherms type is different for the samples with and without diol. Thus, the
specific surface areas have values <11 m2/g for the samples without diol and >200 m2/g for the samples with diols, depending on the annealing temperature. 相似文献
6.
Vinyltri(phenylethynyl)silane ((ph–C≡C)3–Si–C=CH2; VTPES) and phenyltri(phenylethynyl)silane ((ph–C≡C)3–Si–ph; PTPES) were synthesized by Grignard reaction. Their molecular structures were characterized by means of 1H NMR, 13C NMR, 29Si NMR, and FT-IR spectroscopy. Their nonisothermal thermal curing processes were characterized by DSC, and the corresponding
kinetic data, for example activation energy (E), pre-exponential factor (A), and the order of the reaction (n), were obtained by the Kissinger method. The results showed that the melting points of VTPES and PTPES were 84 and 116 °C,
respectively. Their curing reaction rates were consistent with first-order kinetic equations. VTPES monomer had a lower activation
energy and curing temperature as a result of coordination between reactive groups. 相似文献
7.
Atanu Jana Chinmoy Bhattacharya Subrata Sinha Jayati Datta 《Journal of Solid State Electrochemistry》2009,13(9):1339-1350
Bismuth sulfide (Bi2S3) thin films were electrodeposited from non-aqueous dimethyl sulfoxide medium containing Bi(NO3)3 and thiourea as the precursor salts, triethanol amine as the complexing agent, and TritonX-100 as the surface active agent.
The prepared films were subjected to rigorous experimentation in order to validate their potential candidature for solar cells.
The films exhibited band gap energy of ∼1.3 eV and resistivity of the order of 2 × 106 Ω cm at room temperature as was obtained from UV–Vis spectroscopy and four-probe measurements, respectively. Scanning electron
microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive analysis of X-ray were employed to
reveal the morphology, structure, and chemical composition of the film matrix. The Bi2S3 films were found to be non-decomposable up to the temperature of 1,000 °C with the help of thermogravimetry–differential
thermal analysis. The Nyquist and Mott–Schottky plots derived from electrochemical impedance spectroscopy measurements provided
important information regarding electrical and semiconducting properties of the films. The n-type film with a donor density of the order of ∼1023 m−3 displayed reasonable photoactivity under illumination and is recommended as a promising candidate for potential photoelectrochemical
applications. 相似文献
8.
Yu Huimei Qi Lingjun Zhang Qinghong Jiang Danyu Lu Changwei 《Journal of Thermal Analysis and Calorimetry》2011,106(1):47-52
The thermal behavior of the anticancer drug-irinotecan was measured by Thermogravimetry–Differential thermal analysis (TG–DTA)
to explore the application of TG–DTA in nanomedicine firstly. The TG–DTA result showed that the irinotecan was oxidized completely
before 700 °C. When irinotecan was loaded onto nanosized mesoporous silica spheres, the loading capacity for irinotecan measured
by TG–DTA was about 9.11% in the irinotecan/mesoporous SiO2 composite, similar to the typical UV–Vis spectra results (10.5%), which showed that TG–DTA characterization provided an alternative
method to determine the drug loading amount on inorganic carriers. Secondly, Thermogravimetry–Differential scanning calorimetry–Mass
Spectrometry coupling techniques (TG–DSC–MS) were used to characterize the hydrogen adsorption temperature and capacity of
TiCr1.2 (V-Fe)0.6 alloy. The MS result showed that the released region of hydrogen was 250–500 °C, which was consistent with the TG–DSC results.
Lastly, TA–MS combined with pulse thermal analysis (PulseTA) were used for a simultaneous characterizing study in the changes
of mass, determination and quantitative calibration of the evolved nitrogen formed during the thermal decomposition of the
InN powder. The results showed that relative error of this method between measured value and theoretical value was 2.67% for
the quantitative calibration of evolved N2. It shows that TA–MS combined with PulseTA techniques offer a good tool for the quantification of the evolved nitrogen in
the InN powder. 相似文献
9.
Hou-yin Zhao Yan Cao Song P. Sit Quentin Lineberry Wei-ping Pan 《Journal of Thermal Analysis and Calorimetry》2012,107(2):541-547
The pyrolysis behavior of bitumen was investigated using a thermogravimetric analyzer–mass spectrometer system (TG–MS) and
a differential scanning calorimeter (DSC) as well as a pyrolysis-gas chromatograph/mass spectrometer system (Py-GC/MS). TG
results showed that there were three stages of weight loss during pyrolysis—less than 110, 110–380, and 380–600 °C. Using
distributed activation energy model, the average activation energy of the thermal decomposition of bitumen was calculated
at 79 kJ mol−1. The evolved gas from the pyrolysis showed that organic species, such as alkane and alkene fragments had a peak maximum temperature
of 130 and 480 °C, respectively. Benzene, toluene, and styrene released at 100 and 420 °C. Most of the inorganic compounds,
such as H2, H2S, COS, and SO2, released at about 380 °C while the CO2 had the maximum temperature peaks at 400 and 540 °C, respectively. FTIR spectra were taken of the residues of the different
stages, and the results showed that the C–H bond intensity decreased dramatically at 380 °C. Py-GC/MS confirmed the composition
of the evolved gas. The DSC revealed the endothermic nature of the bitumen pyrolysis. 相似文献
10.
Mu-hua Chen Wei Chu Jun-jie Zhu Lin Dong 《Journal of Sol-Gel Science and Technology》2008,47(3):354-359
Novel cobalt catalysts were prepared by sol–gel method, and enhanced by plasma treatment, for methane catalytic combustion.
These samples were characterized using X-ray diffraction, X-ray photoelactron spectroscopy, UV-vis spectroscopy, Fourier transform
infrared spectroscopy, thermal gravimetrical analysis, N2 Adsorption–desorption, temperature-programmed reduction and hydrogen–oxygen titration technologies. The XPS characterizations
suggested that plasma treatment was favorable for the enrichment of surface cobalt, with a value of surface cobalt from 2.2%
to 8.5% in mole. The specific surface area of the glow plasma assised sample (Co-Plas-Solgel-2) increased to 320 m2/g comparing with 305 m2/g of the conventional sample (Co-Solgel-1). The ignition temperature (T10%) of Co-Plas-Solgel-2 catalyst was about 50 °C lower than that of Co-Solgel-1, and its CH4 conversion was two times higher than that of Co-Solgel-1 during the whole range of catalytic combustion activity test (340–520 °C).
With a better dispersion and more active sites, the plasma assisted sample exhibited significant enhancement in catalytic
performances. 相似文献
11.
Zhirong Mo Faqiong Zhao Fei Xiao Baizhao Zeng 《Journal of Solid State Electrochemistry》2010,14(9):1615-1620
Gold–platinum (AuPt) alloy particles were fabricated directly on multi-walled carbon nanotubes (MWNT)–ionic liquid (i.e.,
trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, [P6,6,6,14][NTf2]) composite coated glassy carbon electrode (GCE) by electrodeposition method. Scanning electron microscope image showed that
they were well-dispersed nanocluster consisting of smaller nanoparticles, and their size was about 70 nm. X-ray diffraction
experiment showed that they were single-phase alloy nanomaterial, and the calculated composition was consisting with that
obtained by energy dispersive X-ray spectroscopy. The resulting modified electrode (i.e., AuPt–MWNT–[P6,6,6,14][NTf2]/GCE) presented high catalytic activity for the electrochemical oxidation of cysteine. The peak potential of cysteine shifted
to 0.42 V (versus saturated calomel electrode) in 0.1 M H2SO4 and the peak current increased greatly in comparison with that on the corresponding Pt (or Au)–MWNT–[P6,6,6,14][NTf2]/GCE. Under the optimized conditions, the oxidation current of cysteine at 0.45 V was linear to its concentration in the
range of 5.0 × 10−7 ∼ 4.0 × 10−5 M with a sensitivity of 43.8 mA M−1. 相似文献
12.
Annamária Krajníková Katarína Győryová Daniela Hudecová Jana Kovářová Zuzana Vargová 《Journal of Thermal Analysis and Calorimetry》2011,105(2):451-460
New zinc(II) 2-bromobenzoate complex compounds with general formula Zn(2-BrC6H4COO)2·nL·xH2O (where L = urea, nicotinamide, N-methylnicotinamide, N,N-diethylnicotinamide, isonicotinamide, phenazone n = 0–2, x = 0–2) were prepared and characterized by elemental analysis, IR spectroscopy and thermal analysis. The thermal decomposition
of hydrated compounds started with dehydration process. During the thermal decomposition organic ligand, carbon dioxide and
bis(2-bromophenyl)ketone were evolved. The solid intermediates and volatile products of thermal decomposition were proved
by IR spectroscopy and mass spectrometry. The final solid product of the thermal decomposition heated up to 1073 K was zinc
oxide. Antimicrobial activity of the prepared compounds was tested against various strains of bacteria, yeasts and filamentous
fungi (E. coli, S. aureus, C. albicans, R. oryzae, A. alternate and M. gypseum). It was found that the selected bacteria were more sensitive to the studied zinc(II) complex compounds than the yeast and
the filamentous fungi. 相似文献
13.
Lucica Viorica Ababei Angela Kriza Adina Magdalena Musuc Cristian Andronescu Elena Adina Rogozea 《Journal of Thermal Analysis and Calorimetry》2010,101(3):987-996
New complexes of 2-benzoyl-pyridil-isonicotinoylhydrazone (L) with Cu(II), Co(II), Ni(II) and Mn(II), having formula of type
[ML2] SO4·xH2O (M = Cu2+, Co2+, Ni2+, x = 2 and M = Mn2+, x = 3), have been synthesised and characterised. All complexes were characterised on the basis of elemental analyses, IR spectroscopy,
UV–VIS–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The thermal behaviour
of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry
(DSC). The structure of L hydrazone was established by X-ray study on single crystal. The ligand works as tridentate NNO,
being coordinated through the azomethine nitrogen, the pyridine nitrogen and carbonylic oxygen. Heats of decomposition, ΔH, associated with the exothermal effects were also determined. 相似文献
14.
M. R. Sovizi 《Journal of Thermal Analysis and Calorimetry》2010,102(1):285-289
Data on the thermal stability of drugs was required to obtain information for handling, storage, shelf life and usage. In
this study, the thermal stability of two nonsteroidal anti-inflammatory drugs (NSAIDs) was determined by differential scanning
calorimetry (DSC) and simultaneous thermogravimetery/differential thermal analysis (TG/DTA) techniques. The results of TG
analysis revealed that the main thermal degradation for the naproxen and celecoxib occurs in the temperature ranges of 196–300
and 245–359 °C, respectively. The TG/DTA analysis of compounds indicates that naproxen melts (at about 158.1 °C) before it
decomposes. However, the thermal decomposition of the celecoxib started about 185 °C after its melting. The influence of the
heating rate (5, 10, 15, and 20 °C min−1) on the DSC behavior of the both drug samples was verified. The results showed that, as the heating rate was increased, decomposition
temperatures of the compounds were increased. Also, the kinetic parameters such as activation energy and frequency factor
for the compounds were obtained from the DSC data by non-isothermal methods proposed by ASTM E696 and Ozawa. Based on the
values of activation energy obtained by various methods, the following order for the thermal stability was noticed: naproxen
> celecoxib. Finally, the values of ΔS
#, ΔH
#, and ΔG
# of their decomposition reaction were calculated. 相似文献
15.
Karla Calfumán María Jesus Aguirre Diego Villagra Claudia Yañez Carmen Arévalo Betty Matsuhiro Leonora Mendoza Mauricio Isaacs 《Journal of Solid State Electrochemistry》2010,14(6):1065-1072
In this work, the modification of a glassy carbon electrode with tetraruthenated porphyrins electrostatically assembled onto
a Nafion film, previously adsorbed on the electrode surface, is reported. This modified electrode was characterized by scanning
electron microscopy–energy-dispersive X-ray, Raman spectroscopy, UV-Vis spectroelectrochemistry, and cyclic voltammetry. The
Nafion film onto the glassy carbon electrode shows a smooth disposition; when the tetraruthenated porphyrin is incorporated
on the Nafion film, the complex is adsorbed in a homogeneous way. The modified electrode catalyzes HSO3− oxidation in water–ethanol solutions and shows an enhanced stability compared with the electrode modified with the dip coating
method. Rotating disk electrode experiments showed a kinetic limitation to the electron transfer controlled by charge propagation
in the film. I/E curves show a Tafel slope of 120 mV/decade corresponding to a first electron-transfer reaction, depending on the potential,
as the determining step. Spectroelectrochemical experiments demonstrated that Ru(II) is the active site for the electrocatalysis. 相似文献
16.
S. C. Mojumdar L. Raki N. Mathis K. Schimdt S. Lang 《Journal of Thermal Analysis and Calorimetry》2006,85(1):119-124
A non-ionic polymer (poly(vinyl
alcohol) (PVA)) has been incorporated into the inorganic layers of calcium
silicate hydrate (C–S–H) during precipitation of quasicrystalline
C–S–H from aqueous solution. C–S–H and a C–S–H-polymer
nanocomposite (C–S–HPN) material were synthesized and characterized
by X-ray fluorescence (XRF), energy dispersive spectroscopy (EDS), 29Si
magic angle spinning nuclear magnetic resonance (29Si
MAS NMR) and 13C cross-polarization nuclear magnetic
resonance (13C CP NMR) spectroscopy, atomic force
microscopy (AFM), thermal conductivity, thermogravimetric analysis (TG) and
differential thermal analysis (DTA). Thermal conductivity of PVA, C–S–H
and C–S–HPN material was studied in the temperature range 25–50°C.
C–S–HPN materials exhibited the highest thermal conductivity at
25 and 50°C. The thermal conductivity increases from 25 to 50°C are
7.03, 17.46 and 14.85% for PVA, C–S–H and C–S–HPN
material, respectively. Three significant decomposition temperature ranges
were observed on the TG curve of C–S–HPN material. 相似文献
17.
Jian-Hua Yi Feng-Qi Zhao Ying-Hui Ren Si-Yu Xu Hai-Xia Ma Rong-Zu Hu 《Journal of Thermal Analysis and Calorimetry》2010,100(2):623-627
The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential
scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques
of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal
decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d)
basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from
HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking
in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one.
The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO− is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal
decomposition experiment.
相似文献
18.
Carboxymethyl cellulose Sn(IV) phosphate composite nano-rod like cation exchanger with diameter in the range of 20–40 nm,
length in the range of 100–150 μm and particle size in the range of 21–38 nm have been successfully prepared by surfactant
assisted sol–gel method. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, fourier
transform infra red spectroscopy and thermogravimetric analysis-differential thermal analysis studies were carried out to
study the structure and morphology of this composite nano-rod like cation exchanger. Freundlich adsorption isotherm is well
fitted for the adsorption of pyridine on the surface of this composite nano-rod like cation exchanger. The thermodynamic parameters
such as Freundlich constant, thermodynamic equilibrium constant (K
0), standard free energy changes (ΔG
0), standard enthalpy changes (ΔH
0) and standard entropy changes (ΔS
0) have been evaluated. These parameters indicated that the adsorption of pyridine on the surface of composite nano-rod like
cation exchanger was feasible, spontaneous and exothermic in nature which suggests for the potential application of pyridine
removal from water. 相似文献
19.
Catalin Tanase Aurel Pui Adrian Oprea Karin Popa 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):563-567
The present study follows the extent of translocation radioactivity from the substrates of the Crucea uranium mining area
to the macromycetes spontaneously occurred during June–October 2008. To this end, radioactivity measurements (gross α + β
and 137Cs) on both macromycetes and their substrates were made. The resultants obtained were confirmed by FT-IR spectroscopy, evidencing
the presence of characteristic bands around of 910 cm−1, corresponding to the asymmetric stretching vibration of the uranyl unit and to the interaction between the UO2
2+ ions and the group belonging to various cellular components. 相似文献
20.
M. Espinosa E. Terres S. Pacheco R. Mejia R. Rodriguez 《Journal of Sol-Gel Science and Technology》2010,53(2):239-245
New mesoporous materials were produced incorporating, at the beginning of the SBA-15 sol–gel synthesis, three different metalloporphyrins:
m-5,10,15,20-TPP-Ni2+, Etio-III-Ni2+, Etio-III-VO2+. These materials have the well-known hexagonal structure characteristic of SBA-15 with some differences: the presence of
the porphyrins modifies the micelles generated during the sol–gel process changing the textural properties of the SBA-15-Porphyrins.
Even when the hexagonal structure was preserved, the order in the crystalline structure was maintained only for short distances
producing pores of different sizes and wider pore size distributions. UV–Vis results showed that the porphyrins are strongly
adsorbed on SBA-15 through the interaction of their π electrons with the superficial hydroxyl groups of the support. This
was confirmed by thermogravimetric results that show a high degree of incorporation of the porphyrins on the SBA-15 and a
high thermal stability. 相似文献