Molecular Design,Synthesis,and Properties Of Nitrogen-rich Triazole Energetic Ionic Liquids

Nitrogen-rich energetic ionic liquids?EILs?as new high energetic materials are applied in the field of modern military,science,etc.Many researchers are interested in azole EILs,because of the molecular structures containing a large number of C-N,N-N and C=N to make their formation enthalpy higher.Azole derivatives contain a plenty of types such as imidazole,triazole,tetrazole and pentazole.Nitrogen-rich triazole EILs have incomparable advantages.They possess higher nitrogen content and enthalpy of formation than imidazole.The thermal stability and safety of triazole EILs are better than most tetrazole and the synthesis conditions and operability of triazole are easier than tetrazole and pentazole,especially the preparation conditions of pentazole being particularly harsh and unstable.1,2,4-triazole are relative easier to synthesis and better thermal stability than 1,2,3-triazole.Through the design of substituent group of 1,2,4-triazole,it may be obtained the required properties to apply in high energy explosive,propellant,gas generating agent,etc.On the basis of the molecular designing,a series of nitrogen-rich EILs based upon4-amino-1,2,4-triazolium are synthesized.The structures are optimization ayalyzed by Gaussian09 software with DFT/B3LYP/6-311+G?d,p?and DFT/B3LYP/LANL2DZ in order to obtain the stable micromolecular structures,charge distribution,interaction energies of ion pairs,dipole moment,electronic structure,etc.Their standard molar volume,standard molar heat capacity and standard molar enthalpy of formation,lattice energy,etc.are calculated by DFT/B3LYP/6-311+G?d,p?and B3LYP/LANL2DZ and further researched.The relationship of molecular structure and physicochemical and thermodynamic properties are discussed systematically.It is possible to estimate the thermodynamics of the process to see if a given synthetic strategy is possible.The main contents in this work are carried out as follows.1-alkyl/esteryl-4-amino-1,2,4-triazolium nitrate,1-butyl-4-amino-1,2,4-triazolium with inorganic anions and nitroimidazole anions and 1-butyl-4-amino-1,2,4-triazolium based on transition metal complex anions are synthesized using change anion reaction.The structures are characterized by ¹H NMR,FT-IR,Raman and UV-Vis.The optimized structures and theoretical IR spectra of[Co?NO₂?₆]^3-,[Co?CN?₆]^3-,[Co?NCS?₄]^2-and[Fe?CN?₆]^3-have been optimized using DFT/B3LYP/LANL2DZ.Combined with the theoretical IR spectra,1-butyl-4-amino-1,2,4-triazolium based on transition metal complex anions are analyzed by FT-IR and Raman.With B3LYP/6-311+G?d,p?and B3LYP/LANL2DZ,the mechanism of the alkylation reaction for the intermediate[RATZ]Br ILs with straight haloalkane and the metathesis reaction for the nitrogen-rich triazole EILs are discussed using DFT,and the transition state and product structure are confirmed.The saturated vapor pressures,densities,solubility,thermostability,heats of combustion,specific heat capacities,etc.are measured.The themodynamics function data relative to the reference temperature?298 K?are obtained based on the C_p from 303-353 K.The influences of temperature,molecular structure and interaction energy of ion pairs on?and C_p are also discussed systematically.In addition,the density and thermodynamic properties of EILs are deduced from theoretical calculation and experimental evidences.The oxygen balance and CO balance of the synthesized nitrogen-rich triazole EILs are obtained by calculation formula.In the theoretical calculation and molecular design,based on the quantum chemical theory methods and combined with the experimental standard molar formation enthalpies and densities,the explosion heat,detonation velocity,detonation pressure,specific volume of explosion and explosion temperature are estimated by Kamlet-Jacobs formula.The influence of molecular structure on these detonation performance are discussed systematically.On the groundwork of common trigger bond,the sensitivity of EILs are predicted by DFT.The influences of oxygen balance OB_l00,E_LUMO,activity index F,D_H on the sensitivity are researched systematically.Based on the reaction equation under the ideal state,the specific impulse of the nitrogen-rich triazole EILs are calculated using the CEA software of NASA.The ignitability performance of these EILs are determined by high speed photography optical instrument combined with ignition simulation equipment.As a result,through the combustion performance by theoretical calculation method states that the above EILs can be applied in the field of modern military,science,etc.