Exothermic Behavior of Thermal Decomposition of Sodium Percarbonate: Kinetic Deconvolution of Successive Endothermic and Exothermic Processes

Abstract

This study focused on the kinetic modeling of the thermal decomposition of sodium percarbonate (SPC, sodium carbonate-hydrogen peroxide (2/3)). The reaction is characterized by apparently different kinetic profiles of mass-loss and exothermic behavior as recorded by thermogravimetry and differential scanning calorimetry, respectively. This phenomenon results from a combination of different kinetic features of the reaction involving two overlapping mass-loss steps controlled by the physico-geometry of the reaction and successive endothermic and exothermic processes caused by the detachment and decomposition of H2O2(g). For kinetic modeling, the overall reaction was initially separated into endothermic and exothermic processes using kinetic deconvolution analysis. Then, both of the endothermic and exothermic processes were further separated into two reaction steps accounting for the physico-geometrically controlled reaction that occurs in two steps. Kinetic modeling through kinetic deconvolution analysis clearly illustrates the appearance of the net exothermic effect is the result of a slight delay of the exothermic process to the endothermic process in each physico-geometrically controlled reaction step. This demonstrates that kinetic modeling attempted in this study is useful for interpreting the exothermic behavior of solid-state reactions such as the oxidative decomposition of solids and thermal decomposition of oxidizing agent.

Kinetic and Thermodynamic Studies on Synthesis of Mg-Doped LiMn2O4 Nanoparticles

“…For kinetic analysis of entire thermal decomposition process of polymeric matrix, total reaction rate of complex solid-state reactions was expressed as the sum of five individual kinetic processes according to a scheme of successive reactions [ 75 , 76 , 77 , 78 ]: where is the number of individual reactions and is the weighting coefficient representing the contribution factor of each reaction . Likewise, weighting coefficients were subject to two restrictions: and .…”

Efficient Active Oxygen Free Radical Generated in Tumor Cell by Loading-(HCONH2)·H2O2 Delivery Nanosystem with Soft-X-ray Radiotherapy

“…Judging by the position of these peaks that appeared, the observed bonds were assigned to the carbon hydrogen bond (δ C–H at 1390 cm −1 ), the carbonyl group (ν C=O at 1685 cm −1 ) and the amide (δ N–H at 1311 cm −1 ) [ 40 ]. The peak at 1560 and 951 cm −1 is attributed to the absorption of H 2 O 2 [ 41 ]. The IR spectrum of FPO@HMSNs ( Figure 3 e) and FPO@HMSNs-PAA ( Figure 3 f) were almost consistent with that of native FPO ( Figure 3 d), manifesting the presence of FPO in these nano-carriers.…”

Kinetic analysis of overlapping multistep thermal decomposition comprising exothermic and endothermic processes: thermolysis of ammonium dinitramide

“…7,[14][15][16][17][18][19] Considering the thermoanalytical approaches to heterogeneous multistep reactions, further complications are introduced when the overall reaction comprises partially overlapping processes with oppositely signed thermoanalytical signals, e.g., mass loss and mass gain [20][21][22] or exothermic and endothermic events. 23 When two overlapping mass-loss processes indicate endothermic and exothermic effects, respectively, the apparent kinetic data recorded using differential scanning calorimetry (DSC) are different from those recorded with thermogravimetry (TG), as has been shown for isopropylammonium nitrate decomposition. 24 This type of process with superimposed oppositely signed thermal effects has also been observed during kerogen pyrolysis.…”

“…24 This type of process with superimposed oppositely signed thermal effects has also been observed during kerogen pyrolysis. 25 Sophisticated kinetic deconvolution technique has been applied to this type of solidstate reaction, as reported for the thermal decompositions of sodium percarbonate 23 and tin(II) oxyhydroxide. 22 Through kinetic deconvolution analysis, the kinetic parameters for constituent reaction steps with opposite thermoanalytical signals have been linked with the physico-chemical and physico-geometrical features of the transformations.…”