Developing a Theoretical Approach for Accurate Determination of the Density and Thermochemical Properties of Energetic Ionic Liquids
KAUST DepartmentChemical Engineering Program
Clean Combustion Research Center
Combustion and Pyrolysis Chemistry (CPC) Group
Physical Science and Engineering (PSE) Division
Permanent link to this recordhttp://hdl.handle.net/10754/665660
MetadataShow full item record
AbstractEnergetic ionic liquids (EILs) are novel explosives and propellants which are useful for a variety of military and industrial applications. The physicochemical properties of EILs play an important role in determining their performance in practical applications. In this study, a combination of ab initio and empirical methods has been developed to accurately predict the key properties of EILs: a) temperature-dependent heat of formation (ΔHf), entropy (S) and heat capacity (Cp) of cation/anion pairs in the gas phase; b) 298 K density (ρ) and heat of formation (ΔHf) of EILs in the condensed phase. Ab initio methods were selected based on comprehensive validations of the thermochemical properties of closed shell molecules (glyoxal), open shell radicals (vinylperoxy), triplet carbines (oxoethylidene), and the densities of various simple salts (LiF, NaF, KF, MgF2, CaF2, LiCl, NaCl, KCl, MgCl2, CaCl2). The CBS-APNO/G3/G4//M06-2X/6-311++G(d,p) level of theory was selected for the calculation of geometries, frequencies, energies, etc., and the CBS-APNO level of theory was chosen for calculating the original volumes of cations and anions. The proposed methods/approach calculated: a) the gas-phase thermochemistry of the cation/anion pairs of simple salts (Li+, Na+, K+, Mg2+, Ca2+, F− and Cl−) and six triazolium-based energetic salts (ESs) or EILs representatives (3-azido1,2,4-triazolium, 1-methyl-3-azido-1,2,4-triazolium, 1,4-dimethyl-3-azido-1,2,4-triazolium, nitrate and perchlorate), b) the condensed-phase density, lattice energy and heat of formation of ESs/EILs (3-azido1,2,4-triazolium nitrate, 3-azido-1,2,4-triazolium perchlorate, 1-methyl-3-azido-1,2,4-triazolium nitrate, 1-methyl-3-azido-1,2,4-triazolium perchlorate, 1,4-dimethyl-3-azido-1,2,4-triazolium nitrate and 1,4-dimethyl-3-azido-1,2,4-triazolium perchlorate). In comparison with experimental and theoretical results in literature, excellent agreement was observed for all properties. Overall, discrepancies were less than 10 %, a clear indication of the reliability of proposed methods/approach.
CitationLi, Y., Oommen, C., & Sarathy, S. M. (2020). Developing a Theoretical Approach for Accurate Determination of the Density and Thermochemical Properties of Energetic Ionic Liquids. Propellants, Explosives, Pyrotechnics. doi:10.1002/prep.202000071
SponsorsThe authors acknowledge the KAUST Supercomputing Laboratory(KSL) for providing the computing resources and technical sup-ports. This work was supported by the KAUST Office of Sponsored Research with funding to the Clean Combustion Research Center.