Correlation of the Melting Points of Potential Ionic Liquids (Imidazolium Bromides and Benzimidazolium Bromides) Using the CODESSA Program

Katritzky, Alan R.; Jain, Ritu; Lomaka, Andre; Petrukhin, Ruslan; Karelson, Mati; Visser, Ann E.; Rogers, Robin D.

doi:10.1021/ci0100494

Cited by 200 publications

(138 citation statements)

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“…2 The details of how the chemical structure of the ionic liquid affects these various physical characteristics are now beginning to emerge. [3][4][5][6] Less understood, but now of great interest, are the associated chemical properties that manifest in the condensed phase such as relative basicity (or acidity), oxidative (or reductive) capacity, thermal stability, electrochemical reactivity, and catalytic or combustion efficiency of the component ions. [7][8][9] Recent interest in room temperature ionic liquids has grown immensely, as their synthetic routes have been optimized.…”

Section: Introductionmentioning

confidence: 99%

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

et al. 2008

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/RZS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-70448 AFRL-RZ-ED-JA-2008-090 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA# 08149A) SUPPLEMENTARY NOTESPublished in J. Phys. Chem. A 2008, 112, 7816-7824. © 2008 American Chemical Society. ABSTRACTA class of room temperature ionic liquids (RTILs) that exhibit hypergolic activity towards strong nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier Transform infrared (FTIR) spectroscopy of the pre-ignition phase indicates the evolution of N 2 O from both the dicyanamide and azide RTILs. Evidence for the evolution of CO 2 and isocyanic acid (HNCO) with similar temporal behavior to N 2 O from reaction of the dicyanamide ionic liquids with nitric acid is presented. Evolution of HN 3 is detected from the azides. No evolution of HCN from the dicyanamide reactions was detected. From the FTIR observations, biuret reaction tests and initial ab initio calculations, a mechanism is proposed for the formation of N 2 O, CO 2 and HNCO from the dicyanamide reactions during pre-ignition. SUBJECT TERMS SECURITY CLASSIFICATION OF:17 ReceiVed: April 28, 2008; ReVised Manuscript ReceiVed: June 2, 2008 A class of room-temperature ionic liquids (RTILs) that exhibit hypergolic activity toward fuming nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier transform infrared (FTIR) spectroscopy of the preignition phase indicates the evolution of N 2 O from both the dicyanamide and azide...

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Section: Introductionmentioning

confidence: 99%

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

et al. 2008

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“…Many different ILs can be generated by the combination of their cations and anions. Since, their physical and chemical properties can be fine-tuned by combinations of their ions, or by modifying the chemical structures of the constituent ions, they can be tailored to specific tasks [4]. However, the number of possible combinations of cations and anions is around 10 18 ILs according to Seddon [5].…”

Section: Introductionmentioning

confidence: 99%

Melting-Point Estimation of Ionic Liquids by a Group Contribution Method

2011

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Based on experimental data collected from the literature, a group contribution method for estimating the melting points of imidazolium-, pyridinium-, pyrrolidinium-, ammonium-, phosphonium-, and piperidinium-based ionic liquids (ILs) with common anions is proposed. The method considers the contributions of ionic groups and methylene groups, as additive parameters, and two nonadditive characteristic geometric parameters of cations such as symmetry and flexibility. A total of 293 data points for 136 ILs were used in this study. The average relative deviation and the average absolute deviation of the proposed model are 7.8 % and 22.6 K, respectively. It is concluded that the proposal is useful for the prediction of the melting points for a wide range of ILs. List of Symbols Cations[C n mim] + n-Alkyl-3-methylimidazolium cation [C n eim] + n-Alkyl-3-ethylimidazolium cation Electronic supplementary material The online version of this article (

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“…The compounds we studied include 126 pyridinium bromides [13], 104 imidazolium bromides [14], 45 benzimidazolium bromides [14], and 13 1-substituted 4-amino-1,2,4-triazolium bromide [16]. The melting points vary in a range of 30 -370 8C, most of which are much higher than room temperature with 50% even higher than 150 8C.…”

Section: Data Preparationmentioning

confidence: 99%

“…Among the studies for the prediction of melting point, pioneering work was done by Katritzky et al [13] Using Heuristic Method (HM) in CO-DESSA program, they developed a six-parameter model for 126 pyridinium bromides with squared correlation coefficient R 2 as 0.788, cross-validated R 2 as 0.762, and standard deviation as 23.0 K. The descriptors involved in the correlation model include information content indices, total entropy, and the average nucleophilic reactivity index for an N atom. Shortly after, this group performed a similar study using the same method [14] for 104 imidazolium bromides, divided into three subsets (A, B, C) based on the substituents at position 1, and 45 benzimidazolium bromides (set D). The best five-parameter models were obtained for four subsets.…”

Section: Introductionmentioning

confidence: 99%

“…In our previous work, we have successfully applied PPR in the QSPR study of ion mobility [22]. Here, PPR is used to establish the quantitative relationship between the structures and melting points of diverse set of ILs collected from several references [13,14,16]. To obtain a reliable QSPR model with good predictive ability, an available dataset should be divided into the training and test sets.…”

Section: Introductionmentioning

confidence: 99%

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QSPR Study on the Melting Points of a Diverse Set of Potential Ionic Liquids by Projection Pursuit Regression

et al. 2009

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A Quantitative Structure -Property Relationship (QSPR) study was carried out to model the melting points for a diverse set of 288 potential Ionic Liquids (ILs) including pyridinium bromides, imidazolium bromides, benzimidazolium bromides, and 1-substituted 4-amino-1,2,4-triazolium bromides. Based on the calculated descriptors by CODESSA program, a Principal Component Analysis (PCA) was performed on the whole data to detect the homogeneities in the dataset and to assist the separation of the data into representative training and test sets. Heuristic Method (HM) and Projection Pursuit Regression (PPR) were used to develop linear and nonlinear models between the descriptors and the melting points. The PPR model gave a high predictive correlation coefficient (R 2 ) of 0.810 and an Average of Absolute Relative Deviation (AARD) of 17.75%, which are better than those by HM model (R 2 ¼ 0.712, AARD ¼ 24.33%) indicating that PPR is better for the prediction of the melting points. In addition, the descriptors selected by HM can give some insight into factors that can affect the melting points, i.e., benzene ring structure, rotatable bonds, branching, symmetry, and intramolecular electronic effects. This information would be very useful in the design of the potential ILs with desired melting points.

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Correlation of the Melting Points of Potential Ionic Liquids (Imidazolium Bromides and Benzimidazolium Bromides) Using the CODESSA Program

Cited by 200 publications

References 17 publications

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Melting-Point Estimation of Ionic Liquids by a Group Contribution Method

QSPR Study on the Melting Points of a Diverse Set of Potential Ionic Liquids by Projection Pursuit Regression

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