关键词: Asymmetrical dicationic ionic liquid, Crystal structure, Decomposition kinetics

Abstract: The structure of a room temperature asymmetrical dicationic ionic liquid (ADIL), 1-(pyridinium-1-yl) propane-(1-methylpiperidinium) bi[bis(trifluoromethanesulfonyl)imide] ([PyC₃Pi][NTf₂]₂), was studied by the X-ray diffraction method.Meanwhile, thermal analysis of [PyC₃Pi][NTf₂]₂ was also studied using non-isothermal thermogravimetric analysis (TGA). The title crystal belongs to the triclinic with space group P1 and unit-cell parameters a=0.95217 (8) nm, b=1.05129 (11) nm, c=1.70523 (14) nm, α=89.759 (8)°, β=80.657 (7)°, γ=68.007 (9)°, and F(000) = 792. Thermal stability and thermal decomposition kinetics of the title compound were also investigated using TGA under the atmosphere of highly pure nitrogen. Heating curves at different rates were correlated with kinetic equations Friedman and ASTM (also called iso-conversion method). The values of average activation E (kJ·mol^-1) and pre-exponential constant lgA are 149.58 kJ·mol^-1 and 8.83, respectively, which were obtained by the two methods. The kinetic model function, activation energy and pre-exponential constant of this reaction using the multivariate non-linear-regression method were f(α)=(1-α)(1+4.1870α), 151.04 kJ·mol^-1 and 8.81, respectively, which were basically consistent with iso-conversion methods.

Key words: Asymmetrical dicationic ionic liquid, Crystal structure, Decomposition kinetics