Thermoanalytical investigations of the decomposition course of copper oxysalts

Abstract

The thermal decomposition course of copper acetate monohydrate (CuAe) was examined on heating up to 600~ at various rates, by TG, DTA and DSC. Non-isothermal kinetic and thermodynamic parameters were determined in air or nitrogen. SEM was used to describe the decomposition course and the solid products were identified by IR and XRD analysis. The results indicated that CuAc was dehydrated at 190~ and then partially decomposed at 220~ giving rise to CuO in addition to a minor portion of CuzO and Cu403. The last two oxides seemed to faeilirate the decomposition of the rest of the anhydrous acetate. Cu20 and Cu403 were oxidized in air at >400~ in a process that did not occur in nitrogen.

Thermokinetic investigation of binary Cu/Zn hydroxycarbonates as precursors for Cu/ZnO catalysts

“…However, the reaction order decreases from stage 2 to 3, which is probably due to the decrease in the nucleation rate [24]. The obtained kinetic parameters agree with the values for the pure malachite [25] and zinc carbonate hydroxide, hydrozincite [26]. It should be noted that the performed analysis reveals the formal macrokinetic mechanism.…”

On verdigris, part I: synthesis, crystal structure solution and characterisation of the 1–2–0 phase (Cu3(CH3COO)2(OH)4)

“…Hence it can be concluded that the decomposition of Cu(CH 3 -COO) 2 leads to the formation Cu and Cu 2 O as described in literature. 32,36 In addition, redox active species like CH 3 -CHO, CH 3 -CO-CH 3 and CO are formed leading to a reduction of CuO and to a synproportion of Cu and CuO yielding Cu 2 O. This would explain the exothermic effects at 250°C to 275°C as the decomposition of pure anhydrous Cu(CH 3 -COO) 2 in inert atmosphere is associated with endothermic effects, only.…”

“…This would explain the exothermic effects at 250°C to 275°C as the decomposition of pure anhydrous Cu(CH 3 -COO) 2 in inert atmosphere is associated with endothermic effects, only. 36 In situ XRPD measurementsdecomposition in air Until the decomposition of the acetate starts (Fig. 7 (3)), the mechanism is independent from the oven atmosphere.…”

On verdigris, part II: synthesis of the 2-1-5 phase, Cu3(CH3COO)4(OH)2·5H2O, by long-term crystallisation from aqueous solution at room temperature

“…S5 ‡); this is in accordance with the literature data of the thermal decomposition of copper(II)-acetate. 40,44 Magnetic properties Fig. 13 displays the inverse magnetic susceptibilities of a 2-1-5 polycrystalline sample versus the temperature measured by applying an external magnetic field of 0.1, 1 and 7 Tesla.…”