RESUMEN
This work provides new insights for the liquid-phase decomposition of bis(triaminoguanidinium) azotetrazolate (TAGzT). The liquid-phase decomposition process was investigated using a combined experimental and computational approach. Sub-milligram samples of TAGzT were heated at rates of about 2000 K s-1 to a set temperature (230 to 260 °C) where liquid-phase decomposition occurred under isothermal conditions. Fourier transform infrared (FTIR) spectroscopy and time-of-flight mass spectrometry (ToFMS) were used to acquire transmittance spectra and mass spectra of the evolved gas-phase species from the rapid thermolysis, respectively. FTIR spectroscopy was also used to acquire the transmittance spectra of the condensate and residue formed from the decomposition. N2, NH3, HCN, N2H4, triaminoguanidine and 3-azido-1,2,4-triazol-4-ide anion were identified as products of liquid-phase decomposition. Quantum chemical calculations were used for confirming the identity of the species observed in experiments and for identifying elementary chemical reactions that formed these species. Based on the calculated free energy barriers of these elementary reactions, important reaction pathways were identified for the formation of each of the product species.
RESUMEN
Electrophoresis techniques are characterized by concentration disturbances (or waves) propagating under the effect of an electric field. These techniques are usually performed in microchannels where surface conduction through the electric double layer (EDL) at channel walls is negligible compared with bulk conduction. However, when electrophoresis techniques are integrated in nanochannels, shallow microchannels or charged porous media, surface conduction can alter bulk electrophoretic transport. The existing mathematical models for electrophoretic transport in multi-species electrolytes do not account for the competing effects of surface and bulk conduction. We present a mathematical model of multi-species electrophoretic transport incorporating the effects of surface conduction on bulk ion-transport and provide a methodology to derive analytical solutions using the method of characteristics. Based on the analytical solutions, we elucidate the propagation of nonlinear concentration waves, such as shock and rarefaction waves, and provide the necessary and sufficient conditions for their existence. Our results show that the presence of surface conduction alters the propagation speed of nonlinear concentration waves and the composition of various zones. Importantly, we highlight the role of surface conduction in formation of additional shock and rarefaction waves which are otherwise not present in conventional electrophoresis.