Synthesis and Determination of the Kinetic Parameters for Non-Isothermal Decomposition of Complexes Ln(thd)3phen
In this work the kinetics of the thermal decomposition of two ß-diketone lanthanide complexes of the general formula Ln(thd)3phen (where Ln = Nd+3 or Tm+3, thd = 2,2,6,6- tetramethyl-3,5-heptanodione and phen = 1,10-phenantroline) has been studied. The powders were characterized by several technique...
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Veröffentlicht in: | Materials science forum 2006-11, Vol.530-531, p.506-512 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | In this work the kinetics of the thermal decomposition of two ß-diketone lanthanide
complexes of the general formula Ln(thd)3phen (where Ln = Nd+3 or Tm+3, thd = 2,2,6,6-
tetramethyl-3,5-heptanodione and phen = 1,10-phenantroline) has been studied. The powders
were characterized by several techniques. Thermal decomposition of the complexes was
studied by non-isothermal thermogravimetry techniques. The kinetic model that best describes
the process of the thermal decomposition of the complexes it was determined through the
method proposed by Coats-Redfern. The average values the activation energy obtained were
136 and 114 kJ.mol-1 for the complexes Nd(thd)3phen and Tm(thd)3phen, respectively. The
kinetic models that best described the thermal decomposition reaction the both complexes
were R2. The model R2 indicating that the mechanism is controlled by phase-boundary
reaction (cylindrical symmetry) and is defined by the function g(α) = 2[1-(1-a)1/2], indicating
a mean reaction order. The values of activation energy suggests the following decreasing
order of stability: Nd(thd)3phen > Tm(thd)3phen. |
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ISSN: | 0255-5476 1662-9752 1662-9752 |
DOI: | 10.4028/www.scientific.net/MSF.530-531.506 |