Ionic Liquids and Ionic Liquid + Solvent Mixtures, Studied by Classical Density Functional Theory

The absorptions of CO2on the 1-butyl-3-methylimidazolium acetate ([Bmi [Ac]) with different substituents are calculated systematically at GGA/PW91 level. Three hydrogen bonds are formed between [A and cations of 1-n-[Bmi [A ([NBmi+) and 1-tert-[Bmi [A ([TBmi+). The interaction between CO2and the [NBmi [A by a C-O bond is much weaker than that with the [TBmi [A by forming a O...O...C...C four member-ring. The chemisorption of CO2on the ion pairs of [NBmi [A is much weaker than that on the [TBmi [A, resulted from the absorption energies analysis. The frontier molecular orbitals shows the electronic density overlap between absorbed CO2and the [A in CO2-[NBmi [A is much weaker than that in [TBmi [A. Therefore, the chemisorption of CO2on the ion pair of [NBmi [A is much weaker than that on the [TBmi [A. The ionic liquids based [NBmi+can be used repetitively, and the adsorbed CO2would be easier desorbed.

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Study on Structure Properties of Pyridine Ionic Liquids of Different Acid-Based Chain Lengths

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.298.51 ◽

2011 ◽

Vol 298 ◽

pp. 51-55 ◽

Cited By ~ 1

Author(s):

Li Min Wang ◽

De Qing Chu

Keyword(s):

Density Functional Theory ◽

Hydrogen Bond ◽

Ionic Liquid ◽

Ionic Liquids ◽

Density Functional ◽

Pyridine Ring ◽

Functional Theory ◽

Chain Lengths ◽

Chlorine Ion ◽

Structure Properties

By density functional theory (DFT) at B3LYP/6-311+G** levels, the pyridine ionic liquid with different substituent length has been studied. The calculated results show that the ionic liquid formed by pyridine and a chlorine ion has two main configurations (CCOOH-PyCl and CCOOHPyPCl). There are three combinative locations in each configuration of anion and cation. When the anion is located in the same location, as the acid length becomes longer, the hydrogen bond length between chlorine ion and hydrogen atom in pyridine ring becomes longer, the binding energy between chlorine ion and pyridine with different acid length becomes stronger.

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Thermal Stability and Decomposition Kinetics of 1-Alkyl-2,3-Dimethylimidazolium Nitrate Ionic Liquids: TGA and DFT Study

Materials ◽

10.3390/ma14102560 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2560

Author(s):

Jianwen Meng ◽

Yong Pan ◽

Fan Yang ◽

Yanjun Wang ◽

Zhongyu Zheng ◽

...

Keyword(s):

Thermal Stability ◽

Density Functional Theory ◽

Ionic Liquids ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Nitrogen Atmosphere ◽

Decomposition Kinetics ◽

Heating Rates ◽

Functional Theory ◽

Kinetics Of

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.

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