Theoretical Study On Structure And Performance Of High Energy Boron-containing Compounds

Having high energy and insensitivity are the developing trend of energetic materials such as propellant and explosives as well as the focus point in the range of energy and military field.Throughout the history,there are generally two ways for exploring the energetic materials,namely researching or synthesizing a new compound and using high energy constituent in the formula for compounding a high energy material,at the same time,binder and desensitizer were added to make a less sensitive mixture.Despite the ways of designing the new type high energy compound,synthesizing is the key to the result,thus,study on the process seems more significant and practical.Among synthesizers,boron attracts more eyesight by its high heat,however,reaction of boron requires oxygen support outside,and the surface oxidation film of boron always deters the release of energy in ignition process.To solve this problem,high energy boron-containing compound was designed with features of high heat value,swift reaction speed and security.The geometry structure,bonding characteristics,thermodynamic stability and optical spectrum of nitro-borane compound were theoretically studied by the ab initio and density functional theory.Theoretical design of new type high energy insensitive compound is inportant.Accordingly,the paper contented as following structure:1 According to the density functional theory B3LYP/6-31+G^*,geometry structure,thermodynamic performance and the bond order of frontier orbital energy level ΔE_gap and Wiberg of the compound forming from BO-to hydrogen atom on benzene ring of TNT were theoretically studied.2 According to the density functional theory B3LYP/6-31+G^*,geometry structure,thermodynamic performance and the bond order of frontier orbital energy level ΔE_gap and Wiberg of the compound forming from BO-to hydrogen atom on benzene ring of TNA were theoretically studied.3 According to the density functional theory B3 LYP,bond length,IR spectrum vibration,thermodynamic performance and the bond order of frontier orbital energy level ΔE_gap and Wiberg of the compound forming from BO-to hydrogen atom on benzene ring of TNP were theoretically studied.4 Approaching through the density functional theory B3 LYP on 6-31+G^* basis set level,the stability of nitrogroup derivatives for B₂H₆ was studied,the enthalpy of formation and explosion heat and other parameters were also theoretically calculated.5 Approaching through the density functional theory B3 LYP on 6-31+G^* basis set level,the stability of nitrogroup derivatives for B₄H₂ was studied,the enthalpy of formation and explosion heat and other parameters were also theoretically calculated.6 Approaching through the density functional theory B3 LYP on 6-31+G^* basis set level,the stability of nitrogroup derivatives for B₅H₉ was studied,the enthalpy of formation and explosion heat and other parameters were also theoretically calculated.The results of theoretical calculation show that:1 The boron oxygen in the derivatives of TNT is triple bonds,the bond order of C-BO is 0.86,of C-NO₂ is 0.90,the C-BO bond is comparatively lower,it shows that the C-BO might be the trigger bond.According to the nature orbital analysis,the frontier orbital energy level ΔE_gap of TNT-（BO）₂ is greater than that of TNT-BO,consequently,the stability of boron oxygen derivate is increasing with the increasing of the substituent.The explosion heat of boron oxygen derivate is clearly greater than TNT by calculation,as a conclusion drew that TNT boron oxygen derivate can be a high explosion heat and insensitivity energetic material.2 The boron oxygen in the derivatives of TNA is triple bonds.According to the nature orbital analysis,it shows that the N-H bond is the most feeble one in boron oxygen derivate and might be trigger of the ignition.The frontier orbital energy level ΔE_gap is increasing with the increasing of the substituent,the stability of compound is increasing.The explosion heat of boron oxygen derivate is clearly greater than TNA by calculation,as a conclusion drew that TNA boron oxygen derivate can be a high explosion heat and insensitivity energetic material.3 The boron oxygen in the derivatives of TNP is triple bonds.According to the nature orbital analysis,with the increase of the substituent,the ΔE_gap increased.It shows that the stability of compound enlarging with the increase of substituent.The explosion heat of boron oxygen derivate is clearly greater than TNP by calculation,as a conclusion drew that TNP boron oxygen derivate can be a high explosion heat and insensitivity energetic material.4 The study using the density functional theory shows that: the explosion pressure and velocity of nitrogroup derivatives for B₂H₆ increased with the increase of the nitro.According to the nature orbital analysis,the ΔE_gap value 459.27 kJ/mol of compound B2H2（NO₂）4 is close to the derivatives of TNT,TNA and TNP,consequently,that means even if the nitro now increased to 4,the acquired nitro-borane is relatively stable enough for energetic material use.5 The comparison between nitrogroup derivatives for B₄H₂ and TNT shows that: the density,explosion velocity and explosion pressure of nitrogroup derivatives for B₄H₂ are relatively lower,however the explosion heat is much more powerful than that of TNT.According to the nature orbital analysis,B4HNO₂ and B4（NO₂）₂ are less stable than B₄H₂,namely,sensitivity of B4HNO₂ and B4（NO₂）₂ is excessive and need to reduce before use.6 According to the nature orbital analysis,the ΔE_gap value of B₅H₉ nitro-derivate is very close to the value of TNT,the stability of these compounds is close to the stability of TNT.The B-NO₂ bond in the compound is relatively weak,and it might be the trigger of the ignition.With the increase of nitro,the explosion velocity and pressure are increasing,the max explosion velocity reaches to 6.98 km/s,and the explosion pressure to 19.87 Gpa.Although the two values are lower than that of TNT,the max explosion heat is 1959.11 J/g,a value much higher than that of TNT.