scholarly journals Study of thermal behavior of phytic acid

2013 ◽  
Vol 49 (2) ◽  
pp. 275-283 ◽  
Author(s):  
André Luis Máximo Daneluti ◽  
Jivaldo do Rosário Matos
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Mass Loss ◽  
Kinetic Study ◽  
Phytic Acid ◽  
Absorption Spectroscopy ◽  
Elemental Analysis ◽  
Reaction Order ◽  
Dehydration Process ◽  
Thermogravimetric Method

Phytic acid is a natural compound widely used as depigmenting agent in galenic cosmetic emulsions. However, we have observed experimentally that phytic acid, when heated to 150 ºC for around one hour, shows evidence of thermal decomposition. Few studies investigating this substance alone with regard to its stability are available in the literature. This fact prompted the present study to characterize this species and its thermal behavior using thermal analysis (TG/DTG and DSC) and to associate the results of these techniques with those obtained by elemental analysis (EA) and absorption spectroscopy in the infrared region. The TG/DTG and DSC curves allowed evaluation of the thermal behavior of the sample of phytic acid and enabled use of the non-isothermal thermogravimetric method to study the kinetics of the three main mass-loss events: dehydration I, dehydration II and thermal decomposition. The combination of infrared absorption spectroscopy and elemental analysis techniques allowed evaluation of the intermediate products of the thermal decomposition of phytic acid. The infrared spectra of samples taken during the heating process revealed a reduction in the intensity of the absorption band related to O-H stretching as a result of the dehydration process. Furthermore, elemental analysis results showed an increase in the carbon content and a decrease in the hydrogen content at temperatures of 95, 150, 263 and 380 °C. Visually, darkening of the material was observed at 150 °C, indicating that the thermal decomposition of the material started at this temperature. At a temperature of 380 °C, thermal decomposition progressed, leading to a decrease in carbon and hydrogen. The results of thermogravimetry coupled with those of elemental analysis allow us to conclude that there was agreement between the percentages of phytic acid found in aqueous solution. The kinetic study by the non-isothermal thermogravimetric method showed that the dehydration process occurred in two stages. Dehydration step I promoted a process of vaporization of water (reaction order of zero), whereas dehydration step II showed an order of reaction equal to five. This change in reaction order was attributed to loss of chemically bonded water molecules of phytic acid or to the presence of volatile substances. Finally, the thermal decomposition step revealed an order of reaction equal to one. It was not possible to perform the kinetic study for other stages of mass loss.

Synthesis, Characterization and Thermal studies of Novel Organomercury Driven from Sulfa Drugs Part 1

2011 ◽  
Vol 7 (2) ◽  
pp. 1338-1347
Author(s):  
Tarek Ali Fahad ◽  
Shaker.A.N. AL-Jadaan
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
1H Nmr ◽  
Elemental Analysis ◽  
Thermal Studies ◽  
Spectroscopic Techniques ◽  
Sulfa Drugs ◽  
Acid Base ◽  
Ph Values ◽  
Multi Stage

Two new heterocyclic Organmercury compounds   were prepared from the reaction of Sulfamethaxazole and Sulfadiazine with 4-acetaminophenol as a coupler and separated as solids with characteristic colors. these compounds were characterized by F.T.IR-spectroscopy 1H-NMR , Micro-elemental Analysis and UV-Vis spectroscopic techniques . The work involves a study of acid – base properties compounds at different pH values, the ionization and protonation constants were calculated. The thermal behavior of these two compounds   were investigated on the basis of thermogravimetric (TGA) and differential thermogravimetric (DTG) analyses, Thermal decomposition of these compounds is multi-stage processes.

scholarly journals Thermal behavior of Sr-form of gordaite

2021 ◽  
Vol 82 (3) ◽  
pp. 19-21
Author(s):  
Zlatka Delcheva ◽  
Tsveta Staminirova ◽  
Nadia Petrova
Keyword(s):  
Thermal Decomposition ◽  
Ion Exchange ◽  
Thermal Behavior ◽  
Mass Loss ◽  
Exchangeable Cations ◽  
Decomposition Products ◽  
Ion Exchange Reaction ◽  
Reaction Data ◽  
Thermal Decomposition Products ◽  
First Time

Cation-exchanged Sr-form of gordaite was successfully obtained from Ca-form of gordaite by an ion-exchange reaction. Data of XRD, SEM-EDS and DTA-TG-MS were used to characterize the Sr-form. Thermal decomposition of Sr-gordaite was studied for the first time in regards of thermal events and mass loss during volatile releasing. It was found similarity with Sr-gordaite and Ca-gordaite in terms of processes, type, and amount of volatiles released, but also some differences were found concerning the temperature correspondence of the volatiles evolving and the type of thermal decomposition products. The influence of the exchangeable cations (Na, Ca, or Sr) on the dehydration of the interlayer in the gordaite type structure were also established.

scholarly journals Characterization and Thermal Analysis of Mercury Complexes Containing Intermolecular N→Hg Interactions

2011 ◽  
Vol 8 (s1) ◽  
pp. S502-S508
Author(s):  
Hajar Sahebalzamani ◽  
Farshid Salimi ◽  
Shahriare Ghammamy
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Thermal Behavior ◽  
Elemental Analysis ◽  
Analytical Methods ◽  
Coordination Mode ◽  
Multi Stage ◽  
Mercury Complexes ◽  
Differential Thermogravimetry

The new mercury (II) compounds with (L1), (L2) of the general formula [Hg(L)2], have been synthesized and characterized by elemental analysis, electronic and IR, Raman spectra and thermogravimetry and differential thermogravimetry techniques. The changes observed between the spectra of the ligands and of the complexes allowed us to stablish the coordination mode of the metal in complexes and the mechanism of C–H activation is discussed in detail. Thermogravimetry (TG), differential thermal analysis (DTA) and other analytical methods have been applied to the investigation of the thermal behavior and structure of the compounds [Hg(L)2]. Thermal decomposition of these compounds is multi-stage processes.

Kinetic study of the second stage of the dolomite thermal decomposition

2008 ◽  
Vol 33 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Haykel Galai ◽  
Michèle Pijolat ◽  
Françoise Valdivieso ◽  
Kais Nahdi ◽  
Malika Trabelsi-Ayadi
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Study ◽  
Second Stage

scholarly journals Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source precursor for antimony sulfide thin films

2021 ◽  
Author(s):  
Jako S. Eensalu ◽  
Kaia Tõnsuaadu ◽  
Jasper Adamson ◽  
Ilona Oja Acik ◽  
Malle Krunks
Keyword(s):  
Thin Films ◽  
Thermal Decomposition ◽  
Mass Loss ◽  
Solid Phase ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Thermal Decomposition Mechanism ◽  
Product Analysis ◽  
Gaseous Species ◽  
Single Source Precursor

AbstractThermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III) (1), a precursor for Sb2S3 thin films synthesized from an acidified aqueous solution of SbCl3 and KS2COCH2CH3, was monitored by simultaneous thermogravimetry, differential thermal analysis and evolved gas analysis via mass spectroscopy (TG/DTA-EGA-MS) measurements in dynamic Ar, and synthetic air atmospheres. 1 was identified by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) measurements, and quantified by NMR and elemental analysis. Solid intermediates and final decomposition products of 1 prepared in both atmospheres were determined by X-ray diffraction (XRD), Raman spectroscopy, and FTIR. 1 is a complex compound, where Sb is coordinated by three ethyldithiocarbonate ligands via the S atoms. The thermal degradation of 1 in Ar consists of three mass loss steps, and four mass loss steps in synthetic air. The total mass losses are 100% at 800 °C in Ar, and 66.8% at 600 °C in synthetic air, where the final product is Sb2O4. 1 melts at 85 °C, and decomposes at 90–170 °C into mainly Sb2S3, as confirmed by Raman, and an impurity phase consisting mostly of CSO 2 2− ligands. The solid-phase mineralizes fully at ≈240 °C, which permits Sb2S3 to crystallize at around 250 °C in both atmospheres. The gaseous species evolved include CS2, C2H5OH, CO, CO2, COS, H2O, SO2, and minor quantities of C2H5SH, (C2H5)2S, (C2H5)2O, and (S2COCH2CH3)2. The thermal decomposition mechanism of 1 is described with chemical reactions based on EGA-MS and solid intermediate decomposition product analysis.

scholarly journals Thermal behavior and decomposition kinetics of rifampicin polymorphs under isothermal and non-isothermal conditions

2010 ◽  
Vol 46 (2) ◽  
pp. 343-351 ◽  
Author(s):  
Ricardo Alves ◽  
Thaís Vitória da Silva Reis ◽  
Luis Carlos Cides da Silva ◽  
Silvia Storpírtis ◽  
Lucildes Pita Mercuri ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Melting Process ◽  
Decomposition Process ◽  
Stable Form ◽  
Thermal Decomposition Process ◽  
Mean Values ◽  
Conversion Level ◽  
Polymorphic Forms ◽  
Crystalline Forms

The thermal behavior of two polymorphic forms of rifampicin was studied by DSC and TG/DTG. The thermoanalytical results clearly showed the differences between the two crystalline forms. Polymorph I was the most thermally stable form, the DSC curve showed no fusion for this species and the thermal decomposition process occurred around 245 ºC. The DSC curve of polymorph II showed two consecutive events, an endothermic event (Tpeak = 193.9 ºC) and one exothermic event (Tpeak = 209.4 ºC), due to a melting process followed by recrystallization, which was attributed to the conversion of form II to form I. Isothermal and non-isothermal thermogravimetric methods were used to determine the kinetic parameters of the thermal decomposition process. For non-isothermal experiments, the activation energy (Ea) was derived from the plot of Log β vs 1/T, yielding values for polymorph form I and II of 154 and 123 kJ mol-1, respectively. In the isothermal experiments, the Ea was obtained from the plot of lnt vs 1/T at a constant conversion level. The mean values found for form I and form II were 137 and 144 kJ mol-1, respectively.

Thermal behavior and kinetic study for co-pyrolysis of lignocellulosic biomass with polyethylene over Cobalt modified ZSM-5 catalyst by thermogravimetric analysis

2018 ◽  
Vol 247 ◽  
pp. 804-811 ◽  
Author(s):  
Zhongping Xiang ◽  
Jianghui Liang ◽  
Hervan Marion Morgan ◽  
Yuanyuan Liu ◽  
Hanping Mao ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Kinetic Study ◽  
Lignocellulosic Biomass

Synthesis and Properties of Tetrakis(trimethylsilyl)-phthalocyaninatoruthenium(II)

1999 ◽  
Vol 03 (03) ◽  
pp. 224-229 ◽  
Author(s):  
KAI DÜRR ◽  
MICHAEL HANACK
Keyword(s):  
Thermal Decomposition ◽  
Elemental Analysis ◽  
Axial Ligands ◽  
Vis Spectroscopy

Tetrakis(trimethysilyl)phthalocyaninatoruthenium(II) (5) has been synthesized via the biaxially coordinated (( CH 3)3 Si )4 PcRu (3- Clpy )2 (2) complex by thermal decomposition of the axial ligands of 2. (( CH 3)3 Si )4 PcRu (5) was characterized by NMR, IR and UV-vis spectroscopy and elemental analysis. The trisubstituted (( CH 3)3 Si )3 PcRu (3- Clpy )2 (3) and disubstituted (( CH 3)3 Si )2 PcRu (3- Clpy )2 (4) complexes, formed as side products during the thermolysis of 2, could be isolated and characterized.

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