Thermal Stability and Kinetic of Decomposition of Mono- and Dicationic Imidazolium-Based Ionic Liquids

Abstract

Phase transitions, thermal stability, thermokinetics and activation parameters of degradation reaction of the dicationic ionic liquids (ILs), 1,n-bis(3-methylimidazolium-1-yl)alkane ([BisAlk(MIM) 2 ][2Br]) and monocationic ILs, 1-(3-methylimidazolium-1-yl)alkane ([Alk(MIM)] [Br]), where Alk = Dec, DoDec, TetDec, (decane, dodecane, tetradecane) were evaluated. The influence of an additional cationic head and the alkyl chain length in thermal parameters were also evaluated. The dicationic ILs are more stable than monocationic and thermal degradation of ILs mono-and dicationic did not show linear dependence on the alkyl chain length. Thermokinetic parameters indicated degradation in multiple steps. The monocationic ILs showed a more persistent crystalline phase than dicationic IL, which became totally amorphous after heating. The estimate temperature decomposition, activation energy and thermal transitions enable the determination of which types of ILs are applicable for specific purposes, such as lubricants or solvents at high temperatures, while maintaining ILs physical and chemical properties.

Thermal Kinetics of Monocationic and Dicationic Pyrrolidinium-Based Ionic Liquids

“…Generally, this indicates a better thermal stability of mono-[C 4 MPyr][Br] compared to [BisC 4 MPyr][Br 2 ]. This result is opposed to studies performed by Bender et al and Fareghi et al, in which they reported a better thermal stability for dicationic imidazolium-based ILs [ 28 , 29 ].…”

“…The E a , log A and R 2 values for both ILs were presented in Table 2 . On the other hand, Bender and co-workers had performed the kinetic decomposition study on mono- and dicationic imidazolium-based ILs coupled with the Br - anion by using the FWO method [ 28 ]. It was determined that the values of kinetic parameters for their imidazolium-based dicationic ILs at α = 0.1 and α = 0.5 are higher than our dicationic pyrollidinium ILs.…”

Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development

“…Figure 16. The values of DILs are 30-40 °C higher than their monocationic counterparts [134][135][136]. Other studies have obtained similar conclusions, which are ascribed to higher charges, higher molecular weight, and greater intermolecular interactions of DILs [6,129,137].…”

“…Tonset of [CnMIM][Br] and [Cn(MIM)2][Br]2 obtained by TGA at a heating rate of 10 °C /min in nitrogen atmosphere[134] (n = 10,12,14).…”