scholarly journals Kinetics and Thermodynamics of Thermal Degradation of Different Starches and Estimation the OH Group and H2O Content on the Surface by TG/DTG-DTA

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 357 ◽  
Author(s):  
Marita Pigłowska ◽  
Beata Kurc ◽  
Łukasz Rymaniak ◽  
Piotr Lijewski ◽  
Paweł Fuć
Keyword(s):  
Thermal Decomposition ◽  
Thermodynamic Parameters ◽  
Kinetic Method ◽  
Hydroxyl Groups ◽  
Activation Process ◽  
Kinetic And Thermodynamic Parameters ◽  
Rate Form ◽  
Low Shear Stress ◽  
Kinetics Of

The main aim of this study is to estimate the kinetic and thermodynamic parameters of thermal decomposition of starches by the Coats–Redfern method. This procedure is a commonly used thermogravimetric analysis/difference thermal gravimetry/differental thermal analysis (TG/DTG-DTA) kinetic method for single rate form. The study also shows a proposed method for reactive hydroxyl groups content on the starch surface determination, and values were in range of 960.21–1078.76 mg OH per 1 g of starch. Thermal processing revealed the thermophysical properties of biomass for the kinetics of decomposition estimation. Activation energies reached the values in range of approximately 66.5–167 kJ·mol−1. This research also enables the determination of the temperature conditions required for becoming the desired form of material. Therefore, it is necessary to achieve the requested compact porous structure in an activation process, because in the native state, the polymer exhibits limited applications as a result of thermal decomposition, low shear stress, retrogradation, and syneresis, hence the low solubility in organic solvents. Thermodynamic parameters and reactive hydroxyl groups in this article review are innovative and have not yet been found in the literature.

Pyrolysis of ficus nitida wood: Determination of kinetic and thermodynamic parameters

Fuel ◽  
2021 ◽  
Vol 283 ◽  
pp. 119253
Author(s):  
A. Tabal ◽  
A. Barakat ◽  
A. Aboulkas ◽  
K. El harfi
Keyword(s):  
Thermodynamic Parameters ◽  
Kinetic And Thermodynamic Parameters ◽  
Ficus Nitida

Kinetic and spectrophotometric studies of binding of iron(III) by glutathione

1976 ◽  
Vol 54 (20) ◽  
pp. 3192-3199 ◽  
Author(s):  
Tahir R. Khan ◽  
Cooper H. Langford
Keyword(s):  
Complex Formation ◽  
Kinetic Method ◽  
Binding Constants ◽  
Chelating Agent ◽  
Formation Reaction ◽  
Spectrophotometric Data ◽  
Natural Water Chemistry ◽  
Kinetics Of ◽  
Sulfur Containing

In this report, determination of unbound aquo iron species is accomplished by a kinetic method involving reaction with sulfosalicylic acid (SSA) on a time scale which is very short with respect to reaction of SSA with the glutathione complexes of iron. The data are used to calculate conditional binding constants for Fe(III) to glutathione. Binding constants in 0.1 M ionic strength media were obtained between pH 1 and 2.4 by the kinetic method, and near pH = 3 by spectrophotometry and by examination of the ratio of rate of complex formation and dissociation. The conditional binding 'constant' between pH 1 and 3 is represented as pK = −1.96 – 0.50pH. This is consistent with the importance of reactions involving only very limited proton release. Spectrophotometric data show that the —OH group on Fe(OH)2+ is lost on glutathione complexing. Kinetics of the complex formation reaction between aquo iron(III) species and glutathione are slower than rates of reaction of iron(III) with simple ligands.The glutathione system is regarded as a model system important to natural water chemistry because it is a widely distributed biological sulfur-containing chelating agent.

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