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T.I. Kashar / Thermochimica Acta 507–508 (2010) 66–70
Table 4
Kinetic parameters of decomposition of acetylacetonato aniline acetohydrazone (AAAH) and its divalent metal complexes.
Complex
Step
n
r
T (K)
Coats–Redfern equation
E* (kJ mol−1
)
ꢃH* (kJ mol−1
)
ꢃS* (kJ mol−1 K−1
)
ꢃG* (kJ mol−1
)
AAAH(H2L·4H2O)
1st
2nd
0.5
0.33
0.9769
0.9961
418
670
0.103146
18773.43
−3.45191
−5.52925
−0.17448
−0.06991
69.48131
41.3115
[Mn(H2L)Cl2·H2O]·4H2O
1st
2nd
3rd
1
0.66
1
0.994
0.9871
0.9958
387
639
963
52.56761
0.04492
660.5979
−3.21476
−5.27925
−7.99516
−0.12332
−0.17786
−0.09471
44.50991
108.3747
83.2115
[Co(H2L)·3H2O]Cl2·3H2O
[Ni(H2L)·3H2O]Cl2·4H2O
[Cu(H2L)·3H2O]Cl2·H2O
[Cu(H2L)·Ac2·H2O]·H2O
[Cu(H2L)·3H2O](NO3)2·H2O
1st
2nd
3rd
0.66
0.66
1
0.9829
0.9862
0.991
400
630
868
24.71155
0.055325
0.350384
−3.32267
−5.20904
−7.20651
−0.12932
−0.17625
−0.15825
48.40439
105.8277
130.152
1st
2nd
3rd
1
0.66
0.66
0.9562
0.9965
0.9942
407
649
881
97.22802
0.06369
2.287629
−3.38034
−5.36061
−7.25186
−0.11779
−0.17483
−0.14253
44.5604
108.1052
118.319
1st
2nd
3rd
0.66
1
0.66
0.9856
0.981
0.9651
484
601
880
30880.2
325.55
0.008083
−3.95001
−4.99011
−7.27859
−0.06848
−0.10451
−0.18946
29.19349
57.8199
159.442
1st
2nd
3rd
1
1
0.5
0.9907
0.9451
0.9901
477
594
840
355.6942
883.056
0.097953
−3.95988
−4.92949
−6.93396
−0.10569
−0.09631
−0.16911
46.45593
52.28115
135.119
1st
2nd
3rd
1
0.66
0.33
0.992
0.988
0.9908
408
620
879
642.213
0.044483
0.000405
−3.38516
−5.1219
−7.29716
−0.10208
−0.17819
−0.21434
38.26429
105.3585
181.1085
third stage is higher than that of the first and second ones. This
indicate that in the first step, the free part of the chelated lig-
step the remainder part is degraded and finally form the repre-
sentative metal oxide. This can be attributed to the structural
rigidity of the chelating ligands, which requires more energy
for its rearrangement to get the correct order compared with
the activated complex [12].
loss of aniline molecules followed by further decomposition. The
energy of activation of the thermal decomposition as determined
from the rate of reaction depends on the nature of the metal ions
being in the order Cu(II) > Mn(II) > Ni(II) > Co(II).
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E*
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4. Conclusion
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