Synthesis, characterization and kinetics of the non-isothermal degradationof copper and cobalt adducts with ethyleneurea, ethylenethiourea and propyleneurea
Rf. De Farias et Lm. Nunes, Synthesis, characterization and kinetics of the non-isothermal degradationof copper and cobalt adducts with ethyleneurea, ethylenethiourea and propyleneurea, TRANSIT MET, 26(4-5), 2001, pp. 477-480
Six adducts of general formula MCl2. 4L (M = Cu and Co; L = ethyleneurea, e
u; ethylenethiourea, etu; and propyleneurea, pu) were prepared and characte
rized by elemental analysis, i.r. spectroscopy and by thermogravimetry (t.g
.). Using the non-isothermal Coats-Redfern method, the kinetic parameters f
or the non-isothermal degradation of the adducts were calculated using ther
mogravimetric data. The i.r. results show that, for eu and pu adducts, coor
dination occurs through oxygen, whereas for etu nitrogen is the donor atom.
All the adducts exhibited a single mass loss step in the t.g. curve, relat
ed to the release of ligand molecules. For eu, etu and pu adducts, the asso
ciated activation energies for the degradation process are: 36.4; 68.07 and
103.07 kJ mol(-1); 67.15; 80.86 and 121.06 kJ mol(-1) for copper and cobal
t adducts, respectively.