Journal of the Brazilian Chemical Society
versão On-line ISSN 1678-4790
ANTUNES, Patrícia A.; BREVIGLIERI, Susete T.; CHIERICE, Gilberto O. e CAVALHEIRO, Éder T. G.. Solution and solid state thermal stability of morpholinedithiocarbamates. J. Braz. Chem. Soc. [online]. 2001, vol.12, n.4, pp. 473-480. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532001000400005.
Thermogravimetric and differential scanning calorimetric investigation of the thermal behavior of NH4+, Mn2+, Co2+, Ni2+ e Cu2+ morpholinedithiocarbamates were performed under nitrogen and air atmospheres in order to investigate the effect, in the thermal decomposition, of the presence of an oxygen as the heteroatom in the amine ring. Decomposition products were identified by their X-ray diffraction patterns. Metal sulfites and oxides were the major residues under nitrogen and air atmospheres, respectively. Spectrophotometric measurements were used to estimate the pKa =3.56 for the morpholinedithiocarbamic acid at 0.50 mol dm-3 ionic strength (NaClO4) at 25.0 °C and kinetic parameters of decomposition at different pH values (klim = 0.14 ± 0.04 s-1 e t½ lim = 5.3 ± 1.2 s).
Palavras-chave : morpholinedithiocarbamates; thermogravimetry; differential scanning calorimetry; decomposition rate constant.