Thermal decomposition of N-butyl-N-methyl pyrrolidinium tetrafluoroborate and N-butyl-N-methyl pyrrolidinium hexafluorophosphate: Py-GC-MS and DFT study

The thermal stability and decomposition mechanisms of pyrrolidinium based ionic liquids (ILs) N-butyl N-methyl pyrrolidinium tetrafluoroborate (Pyr14 BF4) and N-butyl-N- methyl pyrrolidinium hexafluorophosphate (Pyr14 PF6) have been investigated using pyrolysis-GC-MS (Py-GC-MS) and B3LYP/6-311+ +G(d,p) level of density functional theory (DFT). Pyr14 PF6 decomposes through E2 elimination and a bimolecular nucleophilic substitution (SN2) while Pyr1413F4 exhibit SN2 along with a competitive E2 elimination and ring opening pathway. Kissinger method and Ozawa-Flynn-Wall (FN/V0) methods were used for calculating the activation energy parameters for the thermal decomposition of ILs, and are comparable with the computationally calculated activation barriers. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The thermal stability and decomposition mechanisms of two pyrrolidinium based ionic liquids were investigated using Py-GC-MS and DFT, revealing different decomposition pathways and comparable activation energy parameters between experimental and computational methods.