Cytotoxic Pt(IV) and Ru(II) complexes containing a biologically relevant edda-type ligand: A comparative study of their thermal properties

The thermal behaviour of a Pt(IV) and a Ru(II) complex coordinated to O,O'-di-n-butyl-(S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate has been investigated using thermogravimetry (TG) and differential scanning calorimetry (DSC). The study included investigation of the thermal decomposition of these complexes in the temperature range of 30 to 590?C and evaluation of activation energy for the first decomposition steps. For both metal complexes, broad DSC peaks indicated complex thermal transformation processes. The two-step decomposition of the Pt(IV) complex started at 175 and ended at about 418?C, leaving elemental platinum as a final residue. On the other hand, the Ru(II) analogue decomposed in three stages. Thermal degradation was evident beginning at 144?C and suggested the decomposition of a coordinated ligand as dominant process. For this complex, the proposed final residue was RuO2. Kinetic parameters for the first decomposition step were obtained by means of multi-heating rates method, in this case the Kissinger-Akahira-Sunose (KAS) method. The mean activation energy calculated for 0.2 < ? < 0.8 were 122.0 kJ mol?1 for the Pt(IV) and 118.9 kJ mol?1 for the Ru(II) complex and decreased constantly, characteristic of a multi-step process.

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Pyrolysis and Thermogravimetric Study to Elucidate the Bioenergy Potential of Novel Feedstock Produced on Poor Soils While Keeping the Environmental Sustainability Intact

Sustainability ◽

10.3390/su11133592 ◽

2019 ◽

Vol 11 (13) ◽

pp. 3592 ◽

Cited By ~ 5

Author(s):

Muhammad Sajjad Ahmad ◽

Muhammad Aamer Mehmood ◽

Huibo Luo ◽

Boxiong Shen ◽

Muhammad Latif ◽

...

Keyword(s):

Activation Energy ◽

Environmental Sustainability ◽

Plant Biomass ◽

Thermal Transformation ◽

Cost Effective ◽

Product Formation ◽

Heating Rates ◽

Scanning Calorimetry ◽

The Difference ◽

Salt Affected Soils

This work focused on exploring the bioenergy potential of biomass produced on salt-affected soils by growing two types of grasses, namely Parthenium hysterophorus (carrot grass) and Pennesetum benthiumo (mott grass), without using fertilizers or pesticides. The whole plant biomass of both grasses was pyrolyzed at three heating rates (10, 30, and 50 °C min−1) in a joined Thermogravimetry–Differential Scanning Calorimetry (TGA–DSC) analyzer under an inert (nitrogen) environment. The pyrolysis of both grasses was shown to occur in a three-stage process, while most of the thermal transformation occurred at the temperature range of 240–400 °C. The pyrolytic behavior was assessed by estimating the kinetic parameters, using the isoconversional models of Kissenger–Akahira–Sunose and Ozawa–Flynn–Wall. The average values of the activation energy of carrot and mott grasses were shown to be 267 kJ mol−1 (R2 ≥ 0.98) and 188 kJ mol−1 (R2 ≥ 0.98), indicating the suitability of both grasses for co-pyrolysis. Whereas, the difference in the values of enthalpy change and the activation energy was shown to be <~5 kJ mol−1 at each fractional point, which indicated that the product formation was being favored. Moreover, the high heating values of carrot grass (18.25 MJ kg−1) and mott grass (18.63 MJ kg−1) have shown a remarkable bioenergy potential and suitability of co-pyrolysis for both grasses. This study will lead to establishing an energy-efficient and cost-effective process for the thermal transformation of biomass to bioenergy.

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Formation of metal oxide-based hydroxysodalite by alkali-activation of kaolinite

Chemija ◽

10.6001/chemija.v31i3.4286 ◽

2020 ◽

Vol 31 (3) ◽

Author(s):

Ehab AlShamaileh ◽

Muayad Esaifan ◽

Qusay Abu-Afifeh

Keyword(s):

Activation Energy ◽

Metal Oxide ◽

Alkali Activation ◽

Dsc Analysis ◽

X Ray Diffraction ◽

Heating Rates ◽

Scanning Calorimetry ◽

X Ray ◽

Xrd Study ◽

Dsc Curves

The formation of metal oxide-based hydroxysodalite by alkali-activation of kaolinite is studied using X-ray diffraction (XRD) study and differential scanning calorimetry (DSC) analysis. Different metal oxides (CoO, MgO, FeO and SiO2) were used to form the metal oxide-based hydroxysodalite. The transformation from kaolinite into hydroxysodalite is confirmed by XRD. In the thermodynamic study, the maximum peak temperatures for DSC curves at various heating rates were used to determine the activation energy (Ea) of the hydroxysodalite formation. With magnesium oxide and cobalt oxide, the formation process was found to be exothermic while it was endothermic with iron oxide.

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Non-Isothermal Sublimation Kinetics of 2,4,6-Trinitrotoluene (TNT) Nanofilms

Molecules ◽

10.3390/molecules24061163 ◽

2019 ◽

Vol 24 (6) ◽

pp. 1163 ◽

Cited By ~ 1

Author(s):

Walid Hikal ◽

Brandon Weeks

Keyword(s):

Activation Energy ◽

Analytical Techniques ◽

Heating Rates ◽

Scanning Calorimetry ◽

Absorbance Spectroscopy ◽

Calculated Activation Energy ◽

Sublimation Kinetics ◽

Sublimation Rates ◽

First Time ◽

Kinetics Of

Non-isothermal sublimation kinetics of low-volatile materials is more favorable over isothermal data when time is a crucial factor to be considered, especially in the subject of detecting explosives. In this article, we report on the in-situ measurements of the sublimation activation energy for 2,4,6-trinitrotoluene (TNT) continuous nanofilms in air using rising-temperature UV-Vis absorbance spectroscopy at different heating rates. The TNT films were prepared by the spin coating deposition technique. For the first time, the most widely used procedure to determine sublimation rates using thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) was followed in this work using UV-Vis absorbance spectroscopy. The sublimation kinetics were analyzed using three well-established calculating techniques. The non-isothermal based activation energy values using the Ozawa, Flynn–Wall, and Kissinger models were 105.9 ± 1.4 kJ mol−1, 102.1 ± 2.7 kJ mol−1, and 105.8 ± 1.6 kJ mol−1, respectively. The calculated activation energy agreed well with our previously reported isothermally-measured value for TNT nanofilms using UV-Vis absorbance spectroscopy. The results show that the well-established non-isothermal analytical techniques can be successfully applied at a nanoscale to determine sublimation kinetics using absorbance spectroscopy.

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Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽

10.3390/nano10050968 ◽

2020 ◽

Vol 10 (5) ◽

pp. 968 ◽

Cited By ~ 6

Author(s):

Abdenacer Benhammada ◽

Djalal Trache ◽

Mohamed Kesraoui ◽

Salim Chelouche

Keyword(s):

Activation Energy ◽

Thermal Decomposition ◽

Analytical Techniques ◽

Decomposition Reaction ◽

Decomposition Temperature ◽

Heating Rates ◽

Scanning Calorimetry ◽

Nano Catalyst ◽

Average Size ◽

A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

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Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0130 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1357-1359 ◽

Cited By ~ 5

Author(s):

Y. Hongbo ◽

C. Meiling ◽

W. Xu ◽

G. Hong

Keyword(s):

Activation Energy ◽

Thermal Analysis ◽

Layered Double Hydroxides ◽

Heating Rates ◽

Scanning Calorimetry ◽

Exponential Factor ◽

Thermal Kinetic Parameters ◽

Double Hydroxides ◽

Kinetics Of ◽

Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

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Effect of Silica Nanoparticles on Activation Energy of Phenol Novolac Epoxy Resin/Unsaturated Polyester at Various Temperatures

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2019/v34i230122 ◽

2019 ◽

pp. 1-9

Author(s):

Seyyed Mojtaba Mousavi ◽

Seyyed Alireza Hashemi ◽

Ali Mohammad Amani ◽

Amir Savar Dashtaki ◽

Mohammad Reza Jamshidi ◽

...

Keyword(s):

Activation Energy ◽

Silica Nanoparticles ◽

Unsaturated Polyester ◽

Silica Nanoparticle ◽

Heating Rates ◽

Scanning Calorimetry ◽

Ultrasonic Equipment ◽

The Matrix ◽

Tetraethylene Pentamine ◽

Novolac Epoxy

In the current study, the activation energy of modified phenol novolac epoxy (PNE) resin with unsaturated polyester (UPS) and silica nanoparticle (SN) at different filler loadings was investigated. In this case, effect of silica nanoparticles as a nano-size filler on the activation energy of PNE/UPS blend was evaluated. For this matter, tetraethylene pentamine (HA-11) which is an amine hardener was used as curing agent. SNs were dispersed in the mixture using ultrasonic equipment to prevent their agglomeration. The curing reaction of epoxy-based resins is exothermic. In this regard, the dynamic curing process was studied using differential scanning calorimetry (DSC) in four different heating rates, including 2, 5, 10 and 15 °C/min. Besides, various methods, including Ozawa, Flynn-Wall, Friedman and Butchart-Denilez were used to determine whether the activation energy of PNE/UPS blend or the best method for calculation of activation energy. Achieved results showed that the addition of SNs to the matrix can increase the activation energy and thus increase the curing time.

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Kinetics Study on Non-Isothermal Crystallization of Amorphous Alloy Mg65Cu15Ag10Y10

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.413.432 ◽

2011 ◽

Vol 413 ◽

pp. 432-438

Author(s):

Xiao Jun Wang ◽

Tian Dong Xia ◽

Xue Ding Chen

Keyword(s):

Activation Energy ◽

Amorphous Alloy ◽

Heating Rate ◽

Volume Fraction ◽

Strong Dependence ◽

Continuous Heating ◽

Heating Rates ◽

Scanning Calorimetry ◽

Local Activation ◽

Local Activation Energy

The crystallization kinetics of amorphous alloy Mg65Cu15Ag10Y10has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol−1for the heating rates β=5-20 Kmin−1, and 107.5 and 110.0 KJmol−1for the heating rates β=20-80Kmin−1, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin−1is 180.9 KJ mol−1and for heating rates ranging between 20 and 80Kmin−1is 110.2 KJ mol−1. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent,n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

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Crystallization Kinetics in Cu64.5Zr35.5 Binary Metallic Glass

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.727.233 ◽

2017 ◽

Vol 727 ◽

pp. 233-238 ◽

Cited By ~ 2

Author(s):

Qian Gao ◽

Zeng Yun Jian ◽

Jun Feng Xu ◽

Man Zhu

Keyword(s):

Activation Energy ◽

Grain Growth ◽

Crystallization Kinetics ◽

Crystallization Process ◽

Crystallization Kinetic ◽

Heating Rates ◽

Scanning Calorimetry ◽

Growth Activation ◽

Local Activation Energy ◽

Kinetics Of

The crystallization kinetics of melt-spun Cu64.5Zr35.5 amorphous alloy ribbons was investigated using differential scanning calorimetry (DSC) at different heating rates. Besides, the Kissinger and isoconversional approaches were used to obtain the crystallization kinetic parameters. As shown in the results, the activation energies for glass transition and crystallization process at the onset, peak and end crystallization temperatures were obtained by means of Kissinger equation to be 577.65 ± 34, 539.86 ± 54, 518.25 ± 20 and 224.84 ± 2 kJ/mol, respectively. The nucleation activation energy Enucleation is greater than grain growth activation energy Egrowth, indicating that the nucleation process is harder than grain growth. The local activation energy Eα decreases in the whole crystallization process, which suggests that crystallization process is increasingly easy.

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Evaluation the Effect of Amine Type on the Non-isothermally Derived Activation Energy for the Interaction of 3 Antidepressant Drugs with Lactose

Advanced Pharmaceutical Bulletin ◽

10.15171/apb.2019.033 ◽

2019 ◽

Vol 9 (2) ◽

pp. 289-293 ◽

Cited By ~ 1

Author(s):

Faranak Ghaderi ◽

Mahboob Nemati ◽

Mohammad Reza siahi-shadbad ◽

Hadi valizadeh ◽

Farnaz Monajjemzadeh

Keyword(s):

Activation Energy ◽

Antidepressant Drugs ◽

Heating Rates ◽

Scanning Calorimetry ◽

Thermal Methods ◽

Kinetic Evaluation ◽

Pka Value ◽

Preformulation Studies ◽

State Kinetic ◽

Calculated Activation

Purpose: Evaluation of drug-excipients compatibility is an important stage during preformulation studies. In the present research, differential scanning calorimetry (DSC) at different heating rates (2.5, 10, 15°C/min) was applied for the kinetic evaluation of fluvoxamine (FLM), sertraline (SER) and doxepin (DOX) binary mixtures with lactose. Methods: Solid state kinetic parameters of the mixtures were calculated using two different thermal methods including ASTM E698 and Starink and the effect of amine type (pKa value) was investigated based on the calculated activation energies. Results: Based on obtained results mean activation energy calculated for FLM, SER and DOX with lactose using ASTM E698 and Starink methods are equal to 335.23, 132.02 and 270.99 kJ/ mol respectively. Conclusion: Results showed that the probability of drug-lactose interaction is higher in the SERlactose mixture in comparison with other two antidepressant drugs which is consistent with their pKa values.

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Glass transformation temperature and stability of tellurite glasses

Journal of Materials Research ◽

10.1557/jmr.2003.0051 ◽

2003 ◽

Vol 18 (2) ◽

pp. 402-406 ◽

Cited By ~ 14

Author(s):

Raouf El-Mallawany

Keyword(s):

Activation Energy ◽

Differential Scanning Calorimetry ◽

Transformation Temperature ◽

Unit Volume ◽

Tellurite Glasses ◽

Heating Rates ◽

Scanning Calorimetry ◽

Glass Transformation ◽

Glass Series ◽

Calculated Number

The glass transformation (Tg) and onset crystallization temperatures (Tx) of (100 – x) TeO2–(x)V2O5, (x = 10, 35, and 50 mol%) glasses were measured in the temperature range 300–800 K by differential scanning calorimetry at different heating rates. From the variation of the heating rate, the glass transition activation energy was calculated by different methods. The glass stabilization range S = Tx – Tg was calculated for the whole glass series. Quantitative analysis of the glass transformation temperature was carried out using the calculated number of bonds per unit volume and oxygen packing density.

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