Thermal desorption study of catalytic systems. Communication 19. Determination of activation energy for desorption of H2O and CO2 from surface of copper-containing catalysts

1984 ◽  
Vol 33 (6) ◽  
pp. 1129-1134
Author(s):  
V. N. Gel'man ◽  
V. S. Sobolevskii ◽  
E. Z. Golosman ◽  
V. I. Yakerson
Keyword(s):  
Activation Energy ◽  
Thermal Desorption ◽  
Catalytic Systems ◽  
Desorption Study

Thermal desorption study of catalytic systems. 17. Reaction of carbon monoxide with water on the surface of skeletal copper

1982 ◽  
Vol 31 (5) ◽  
pp. 873-876
Author(s):  
V. N. Gel'man ◽  
A. M. Varlamova ◽  
V. S. Sobolevskii ◽  
E. Z. Golosman ◽  
V. I. Yakerson
Keyword(s):  
Carbon Monoxide ◽  
Thermal Desorption ◽  
Catalytic Systems ◽  
Desorption Study ◽  
Skeletal Copper

Development of HPLC Method for the Purity Test by Design of Experiments and Determination of Activation Energy of Hydrolytic Degradation Reactions of Sofosbuvir

2020 ◽  
Vol 16 (7) ◽  
pp. 976-987
Author(s):  
Jakub Petřík ◽  
Jakub Heřt ◽  
Pavel Řezanka ◽  
Filip Vymyslický ◽  
Michal Douša
Keyword(s):  
Activation Energy ◽  
Design Of Experiments ◽  
Mobile Phase ◽  
Hydrolytic Degradation ◽  
Isoconversional Method ◽  
Hplc Method ◽  
Organic Modifier ◽  
Calculation Methods ◽  
Degradation Reactions

Background: The present study was focused on the development of HPLC method for purity testing of sofosbuvir by the Design of Experiments and determination of the activation energy of hydrolytic degradation reactions of sofosbuvir using HPLC based on the kinetics of sofosbuvir degradation. Methods: Following four factors for the Design of Experiments were selected, stationary phase, an organic modifier of the mobile phase, column temperature and pH of the mobile phase. These factors were examined in two or three level experimental design using Modde 11.0 (Umetrics) software. The chromatographic parameters like resolution, USP tailing and discrimination factor were calculated and analysed by partial least squares. The chromatography was performed based on Design of Experiments results with the mobile phase containing ammonium phosphate buffer pH 2.5 and methanol as an organic modifier. Separation was achieved using gradient elution on XBridge BEH C8 at 50 °C and a flow rate of 0.8 mL/min. UV detection was performed at 220 nm. The activation energy of hydrolytic degradation reactions of sofosbuvir was evaluated using two different calculation methods. The first method is based on the slope of dependence of natural logarithm of the rate constant on inverted thermodynamic temperature and the second approach is the isoconversional method. Results and Conclusion: Calculated activation energies were 77.9 ± 1.1 kJ/mol for the first method and 79.5 ± 3.2 kJ/mol for the isoconversional method. The results can be considered to be identical, therefore both calculation methods are suitable for the determination of the activation energy of degradation reactions.

Determination of the surface of powdery substances by the method of thermal desorption using organic vapours as the sorbates

1966 ◽  
Vol 31 (2) ◽  
pp. 450-456 ◽  
Author(s):  
E. Smolková ◽  
L. Krištofíková ◽  
L. Feltl ◽  
O. Grubner
Keyword(s):  
Thermal Desorption
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