Solution and solid state thermal stability of morpholinedithiocarbamates

Thermogravimetric and differential scanning calorimetric investigation of t he thermal behavior of NH4+, Mn-2(+), Co-2(+), Ni-2(+) e Cu-2(+) morpholine dithiocarbamates were performed under nitrogen and air atmospheres in order to investigate the effect, in the thermal decomposition, of the presence o f an oxygen as the heteroatom in the amine ring. Decomposition products wer e 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) a t 25.0 degreesC and kinetic parameters of decomposition at different pH val ues (k(lim) = 0.14 +/- 0.04 s(-1) e t(1/2) (lim) = 5.3 +/- 1.2 s).