Thermal Decomposition Behaviors of Imidazolium-type Ionic Liquids Studied by Pyrolysis-Gas Chromatography

Abstract

Thermal decomposition behaviors of a series of imidazolium-type ionic liquid samples were studied by pyrolysis-gas chromatography at 550˚C using various detectors. As for the imidazolium halides, haloalkanes and 1-alkylimidazoles corresponding to the alkyl substituents were mainly formed through the nucleophilic attacks of halide ions to the alkyl groups followed by C-N bond cleavage, along with a minor amount of alkenes. Meanwhile, in the case of the ionic liquids with BF4, PF6 and CF3SO3 anions, corresponding alkenes were predominantly produced along with 1-alkylimidazoles rather than haloalkanes. No boron-containing products were found even from the samples with BF4 anion, whereas minor but clear peaks of phosphorous-containing products were observed in the pyrograms of the samples with PF6 anions. As for the samples with longer alkyl group, the pyrolyzates reflecting the C-C bond scissions in the alkyl groups were also formed to some extent. Meanwhile, imidazole rings did not decompose under the experimental conditions at around 550˚C.

Cellulases Dig Deep

“…Dehydration with ethanol removes a significant amount of water as well as all of the ionic liquid from this primary gel as confirmed by STA and MS analyses (Fig. 2, supplemental Table S1) (16, 23). Thus, the dehydrated gel is a pure cellulosic substrate.…”

Antimicrobial properties and thermal stability of polycarbonate modified with 1‐alkyl‐3‐methylimidazolium tetrafluoroborate ionic liquids

“…The first step occurs at about 300-350 C and the second one-close to 400 C. The decomposition step at about 300-350 C can be attributed to the PC chemical degradation caused by the products of IL initial thermal degradation. 33 Under an air atmosphere PC/IL samples start to decompose in the similar temperature range (not shown). Thus, one can conclude that the degradation of PC/IL composites does not proceed by thermo-oxidative mechanism.…”

Sandwich-type ordered mesoporous carbon/graphene nanocomposites derived from ionic liquid

“…It is well known that the predominating thermal decomposition pathway of simple, nonfunctional aromatics follows a carbonization process where C-C bonds are formed by C-H bond activation with consecutive H 2 evolution [15,19,20]. The imidazole ring in the cation decomposed at around 400 °C to form ethylene, 1-methylimidazole, and 1-ethylimidazole [25].…”