Kinetic and thermodynamic study of the Na4(UO2)2(OH)4(C2O4)2 complex

Rodante, F.; Vecchio, Stefano; Materazzi, Stefano; Vasca, Ermanno

doi:10.1002/kin.10166

Cited by 7 publications

(2 citation statements)

References 35 publications

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“…Two hydroxooxalato uranates have been reported, Na 4 [(UO 2 ) 2 (C 2 O 4 ) 2 (OH) 4 ] [38,39] with an unknown structure and NH 4 [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)] Á 8H 2 O [37]. In this last compound the structure is built from an other SPBU formed by two OH corner-shared UO 7 pentagonal bipyramids which contain in the equatorial base four oxygen from two oxalate entities that connect the SPBU in a 2D network.…”

Section: Article In Pressmentioning

confidence: 99%

Hydrothermal synthesis and crystal structures of new uranyl oxalate hydroxides: α- and β-[(UO2)2(C2O4)(OH)2(H2O)2] and [(UO2)2(C2O4)(OH)2(H2O)2]·H2O

Duvieubourg

Nowogrocki

Abraham

et al. 2005

Journal of Solid State Chemistry

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Section: Article In Pressmentioning

confidence: 99%

Hydrothermal synthesis and crystal structures of new uranyl oxalate hydroxides: α- and β-[(UO2)2(C2O4)(OH)2(H2O)2] and [(UO2)2(C2O4)(OH)2(H2O)2]·H2O

Duvieubourg

Nowogrocki

Abraham

et al. 2005

Journal of Solid State Chemistry

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“…As Folnak ® constitutes complexly, its degradation reaction is actually parallel, concurrent, or consecutive reaction processes of many elementary reactions (35). In addition, thermogravimetric analysis measures the relationship between the overall quality and temperature, and α denoted that the extent of reaction is just an apparent and integrated concept, which showed that it is impossible that this change of the quality reasonably attributed some one elementary.…”

Section: The Evaluation Of the Kinetic Model Functionmentioning

confidence: 99%

Thermal Stability Investigation and the Kinetic Study of Folnak® Degradation Process Under Nonisothermal Conditions

Jankovi

2010

AAPS PharmSciTech

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Abstract. The nonisothermal degradation process of Folnak ® drug samples was investigated by simultaneous thermogravimetric and differential thermal analysis in the temperature range from an ambient one up to 810°C. It was established that the degradation proceeds through the five degradation stages (designated as I, II, III, IV, and V), which include: the dehydration (I), the melting process of excipients (II), as well as the decomposition of folic acid (III), corn starch (IV), and saccharose (V), respectively. It was established that the presented excipients show a different behavior from that of the pure materials. During degradation, all excipients increase their thermal stability, and some kind of solidsolid and/or solid-gas interaction occurs. The kinetic parameters and reaction mechanism for the folic acid decomposition were established using different calculation procedures. It was concluded that the folic acid decomposition mechanism cannot be explained by the simple reaction order (ROn) model (n= 1) but with the complex reaction mechanism which includes the higher reaction orders (RO, n>1), with average value of =1.91. The isothermal predictions of the third (III) degradation stage of Folnak ® sample, at four different temperatures (T iso =180°C, 200°C, 220°C, and 260°C), were established. It was concluded that the shapes of the isothermal conversion curves at lower temperatures (180-200°C) were similar, whereas became more complex with further temperature increase due to the pterin and p-amino benzoic acid decomposition behavior, which brings the additional complexity in the overall folic acid decomposition process.

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