Ionic liquid thermal stabilities: decomposition mechanisms and analysis tools

Maton, Cédric; Vos, Nils De; Stevens, Christian V.

doi:10.1039/c3cs60071h

Cited by 740 publications

(629 citation statements)

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“…6,8,10,11,13 For ILs, two major factors are found to affect their thermal properties: 1) IL structure; for instance the length of the alkyl group and, cation and anion type; and 2) influence of the environment and impurities, such as heating rate, sample weight, apparatus and pan type, gas flow rate and the presence of oxygen. 13 While the thermal properties of PVC-IL samples have also been studied 7,8,10,11,14 , determination of their thermal degradation products has not. The endless possible combinations of IL cation and anion make it impossible to predict the thermal properties of particular ILs without detailed experiments, further complicated by the degradation mechanism and products of the polymer.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Effect of dual functional ionic liquids on the thermal degradation of poly(vinyl chloride)

Lorenzetti

Choi

Roso

et al. 2016

Polymer Degradation and Stability

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Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Effect of dual functional ionic liquids on the thermal degradation of poly(vinyl chloride)Alessandra Lorenzetti M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractThe short-term thermal stability of PVC on addition of functional ionic liquids (ILs) based on phosphonium and pyridinium cations, and a docusate anion, was studied using FTIR, TGA-MS and TGA-FTIR. The thermal stability of PVC plasticized with these ILs is reduced and the activation energy for thermal degradation for the first step of PVC degradation lowered, relative to neat PVC. This feature is not dependent on the thermal stability of the IL itself, as their addition to neat PVC did not result in increased thermal stability of the resin. Analysis of the gases evolved during thermal degradation showed that there is no variation in the mechanism of PVC degradation in the presence of ILs, the only difference observed is that HCl is evolved at lower temperatures for PVC-ILs samples. The ILs had no effect on the second step of the thermal degradation of PVC. The decrease in the thermal stability of PVC-ILs is associated with two different effects: firstly, the anion weakens the C-H bond while the cation forms complexes and weakens the C-Cl bond; second, the IL interaction with the polymer chains partly substitutes the interaction between the polymer chain and heat stabilizers (e.g. stearates) added to the PVC compound. In this way, the latter tends to be expelled from the bulk polymer, thus not being available for PVC stabilization at high temperature. Heat stabilizer migration is related to the solvating power of the ILs: the higher the solvating power, the higher the migration of heat stabilizer, the lower the thermal stability of the polymer.

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Section: Accepted Manuscriptmentioning

confidence: 99%

Effect of dual functional ionic liquids on the thermal degradation of poly(vinyl chloride)

Lorenzetti

Choi

Roso

et al. 2016

Polymer Degradation and Stability

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“…An appropriate estimation of this property is a key factor in many engineering applications, including lubrication [17]. Despite the fact that a significant number of works have been focused on the study of thermal degradation of ILs [18][19][20][21][22][23][24][25], only a few of them have used phosphonium based ILs [13,15,26]. In addition, thermal stability is often misleadingly reported to extend up to temperatures of more than 400 ºC.…”

Section: Introductionmentioning

confidence: 99%

Isoconversional kinetic analysis applied to five phosphonium cation-based ionic liquids

et al. 2017

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Thermal degradation of five phosphonium cation-based ionic liquids ([P 66614 outperforming the other ones in both pyrolytic and oxidising conditions. Although the thermal degradation mechanism is affected by atmospheric conditions, the degradation trend remains practically constant. As the dynamic methodology usually overestimates the long-term thermal stability, an isoconversional methodology is better for predicting the long-term thermal stability of these ionic liquids in order to be used as base oil or additive in lubricants formulation. Finally, the model-free methodology can predict at lower costs the ILs performance in isothermal conditions. Highlights• Weakly coordinating anions provoke good thermal stability of ILs.• • Isoconversional methods are better than dynamic ones for long-term thermal studies.• Activation energy behavior at low conversions is related to a single reaction.• Model-free methodology can predict the ILs performance in isothermal conditions.

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“…IL containing weakly coordinating anions (less nucleophilic) are generally the most stable. [1,[52][53][54] The most common decomposition mechanism is the formation of alkyl-halide species by SN1 and SN2 nucleophilic substitution mechanisms, [55,56] underlining the importance of the size, the basicity and the nucleophilicity of the anion. The IL stability is consequently inversely proportional to the stability of these alkyl-halides.…”

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confidence: 99%