双环-HMX结构和性质的理论研究

在DFT-B3LYP/6-311G*水平上, 计算研究了高能化合物四硝基四氮杂双环辛烷(双环-HMX) α和β两种异构体的结构和性质. 比较分子对称性、分子内氢键和环张力等几何参数以及分子总能量和前线轨道能级等电子结构参数, 发现α比β稳定. 分子中N—N键较长, N—N键集居数较小, 预示该键为热解和起爆的引发键. 基于简谐振动分析求得IR谱频率和强度. 运用统计热力学方法求得200～1000 K温度的热力学性质. 以非限制性半经验PM3方法探讨其热解机理, 求得各反应通道的过渡态和活化能, 发现热解始于侧链N—NO₂键的均裂. 还从理论上预测了该化合物的密度、爆速和爆压, 有助于寻求高能量密度材料(HEDM).     

3-硝基-1,2,4-三唑-5-酮与NH3及H2O分子间相互作用的理论研究

在DFT-B3LYP/6-311＋＋G**水平上, 求得3-硝基-1,2,4-三唑-5-酮(NTO)/NH₃和NTO/H₂O两种超分子体系势能面上5种全优化构型. 经基组叠加误差(BSSE)和零点能(ZPE)校正, 求得NTO与NH₃和H₂O的分子间最大相互作用能依次为－37.58和－30.14 kJ/mol, 表明NTO与NH₃的分子间相互作用强于与H₂O的作用. 超分子体系中电子均由NH₃或H₂O向NTO转移, 相互作用能主要由强氢键所贡献, 由自然键轨道分析揭示了相互作用的本质. 对优化构型进行振动分析, 并基于统计热力学求得200.0～800.0 K温度范围从单体形成超分子的热力学性质变化. 发现由NTO和NH₃形成超分子II和III在常温下可自发进行; 而NTO和H₂O只在低温下才能自发形成IV, V和VI超分子.     

3,6-二叠氮基-1,2,4,5-四嗪的合成及理论研究

以3,6-双(3,5-二甲基吡唑基)-1,2,4,5-四嗪为原料, 经过肼解反应和重氮化反应, 制得了3,6-二叠氮基-1,2,4,5-四嗪(DAT). 在DFT-B3LYP/6-31G*水平下求得了DAT的分子几何、IR光谱和热力学性质. 计算模拟IR光谱和实测IR光谱的对比表明DAT在固态下不发生叠氮-四唑互变异构反应. 根据IR光谱计算了DAT的热容、焓、熵等热力学参数, 也给出了这些参数和温度T之间的函数关系. 在不破坏四嗪环和叠氮基的原则下通过构建等键反应求得了DAT的精确生成热为1088 kJ•mol^—1. 爆轰性能计算表明DAT爆速D＝8.45 km•s^－1, 爆压P＝31.3 GPa, 高于TNT和HMX.     

ε-六硝基六氮杂异伍兹烷(CL-20)热解机理的理论研究

运用量子化学中非限制性Hartree-Fock自洽场(UHF-SCF) PM3分子轨道(MO)方法, 计算研究六硝基六氮杂异伍兹烷(HNIW或CL-20)的最稳定ε晶型化合物的气相热解引发反应. 求得可能的四种不同热解反应通道的过渡态、活化能和位能曲线, 发现其热解引发步骤为五元环上侧链N—NO₂键的均裂. 在过渡态附近相关原子电荷发生突变.     

几种新型六氮杂异伍兹烷衍生物结构与性能的理论预测—— 高能量密度化合物的寻求

以CN, NC, ONO2, N3, NH2, N2H, NHNH2, N4H和N4H3 9种含氮高能基团为取代基, 分别取代2,4,6,8,10,12-六氮杂异伍兹烷(IW)中亚氨基的6个H原子所形成的9种六氮杂异伍兹烷衍生物作为研究目标分子. 运用密度泛函理论, 在B3LYP/6-31G**水平上求得了它们的分子几何构型、电子结构、解离能(BDE)及IR谱等信息, 并设计等键反应计算了生成热( ). 基于统计热力学原理计算拟合了100～1200 K温度范围内体系的热力学函数, 利用Kamlet-Jacobs方程估算了它们的爆轰性能. 研究结果表明, 9种六氮杂异伍兹烷衍生物存在两种可能的热解引发类型. 在衍生物HNiIW, HBDAIW和HBAIW中, 可能的热解引发键是取代基内部的化学键, 而其余衍生物的热解引发键则可能是骨架N与取代基R之间N—R键. 另外, 硝酸酯基(ONO2)取代所得化合物HNiIW的密度ρ、爆速D及爆压p分别为1.998 g•cm－3, 9.71 km•s－1和44.47 GPa, 完全达到高能量密度化合物(HEDC)的基本要求, 且优于已应用的HNIW, 有望成为新型的HEDC.     

环五甲撑五硝胺(CRX)结构和性质的DFT预示

用密度泛函理论(DFT)B3LYP方法,在6-31G*基组水平下,全优化计算了环五甲撑五硝胺(CRX)的分子几何和优化构型下的电子结构.环C-N键长为0.144～0.148 nm, N-NO2键长为0.139～0.142 nm; CRX的最高占有MO(HOMO)能级和最低未占MO(LUMO)能级之间的差值ΔEg(5.2054 eV)较大,预示CRX较稳定.基于简谐振动分析求得IR谱频率和强度.运用统计热力学方法,求得在200～1200 K的热力学性质C0p,m、 S0m和H0m.还运用Kamlet公式预示了它的爆速和爆压分别为9169 m/s和37.88 GPa.     

Fe2O3纳米粒子的配位聚合物固相热解制备及其储锂性能

以1,4-苯二甲酸为配体,FeCl3为金属盐,采用溶剂热法合成了苯二甲酸-铁配位聚合物晶体.以其为前驱体,通过固相热解制备了尺寸均一的α-Fe₂O₃纳米粒子.利用XRD、FT-IR、SEM及TEM等手段对配位聚合物及其热解产物进行了表征.将α-Fe₂O₃纳米粒子用作锂离子电池负极材料,电化学测试结果表明:在0.1 A·g^-1电流密度下充放电50次后,材料的可逆比容量仍保持在530 mAh·g^-1,表现出较高的比容量和优异的循环稳定性.     

3,6-双(1H-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪的合成、表征及量子化学研究

以三氨基胍硝酸盐、戊二酮为起始原料, 经缩合、氧化、取代等反应合成了3,6-双(1H-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪(BTATz), 并通过元素分析、红外、核磁、差示扫描量热法(DSC)等分析手段对其进行了表征. 采用亚硝酸钠/乙酸代替了二氧化氮/N-甲基吡咯烷酮, 改进了氧化步骤, 降低了成本, 简化了合成工艺. 用B3LYP方法, 在6-31G(d,p)基组水平上对其性能进行了计算, 得到了其稳定的几何构型和键级; 在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质, 并得到了温度对热力学性能影响的关系式; 探讨了其热解机理, 推断出四唑环开环时的过渡态和活化能.     

多硝基四面体烷结构和性能的理论研究

在B3LYP/6-31G**水平下, 对四种四面体烷硝基衍生物进行理论研究. 基于全优化构型, 计算其红外光谱(IR)、热力学性质; 通过设计合理等键反应计算其气相生成热(HOF); 运用Kamlet-Jacobs方程估算其爆速(D)和爆压(p); 通过计算和比较各化合物的两种可能引发键(C—C和C—N)离解能(EC—C和EC—N), 确认该系列化合物的热解引发键和热稳定性. 讨论了各性能参数与其结构参数的关系. 兼顾高能量密度化合物(HEDC)的能量性质和稳定性要求, 最终认为该系列化合物不可作为潜在HEDC.     

新型高能量密度化合物3,6-双(3,5-二硝基-1,2,4-三唑-1)-1,2,4,5-四嗪-1,4-二氧化物的性能预估及合成路线设计

采用C++自编译程序及组合原理,设计并筛选出一种未见报道的新型富氮类高能量密度化合物-3,6-双(3,5.二硝基.1,2,4-三唑.1)-1,2,4,5-四嗪-1,4-二氧化物,用B3LYP法,在6-31G**基组水平上得到该化合物全优化构型;在振动分析的基础上求得体系的振动频率、IR谱;通过键级分析得到热解引发键的键离解能(BDE);采用Monte-Carlo 方法预估了密度;设计等键等电子反应计算了生成焓;运用Kamlet-Jacobs公式预测爆速、爆压和爆热;运用Keshavarz 等推导的预估撞击感度H50的公式预测了撞击感度性能;并利用逆合成分析法设计其合成路线.结果表明:该化合物存在8个强吸收峰,校正后的热解引发键的BDE为264KJ·mol-1,稳定性较优;密度1.955 g·cm-3、生成焓901.72 kJ·mol-1、爆速9191.48 m·s-1、爆压39.32 GPa、爆热6705.15 j·g-1;撞击感度H50为55.85cm,低于黑索金(RDX)和奥克托今(HMx);以上性能均达到了高能量密度化合物的标准,且该化合物设计合成路线步骤较少、原料易得,有望得到广泛应用.     

Superequilibrium increase in the chemical reaction rate in the front and other effects of gas detonation numerically simulated in the channel by instant heating of the flat end

Gas detonation was calculated by the Monte Carlo method at the molecular level on the basis of non-stationary statistical simulation. The detonation was initiated by instant heating of the flat end of the channel. The efficiency of the method and the used block decomposition of the model space is shown. It turned out that an increase in the reaction threshold from 90kТ ₁ to 400kТ ₁ (k is the Boltzmann constant, and Т ₁ is the initial temperature of the gas) resulted in the disappearance of the region of constant parameters behind the front of the detonation wave. The translational non-equilibrium formed in the detonation front strongly increases the rate of the reaction considered at the front edge. The further increase in the reaction threshold leads to the situation where no detonation occurs.     

Synthesis,Structure, and Energetic Properties of 1,5‐Diaminotetrazolium Sulfate Salts

1,5‐diaminotetrazolium chloride (DATC) and 1,5‐diaminotetrazolium sulfate (DATS) were synthesized in this work. The structures of DATS and DATC were characterized. The single crystal of DATS was first cultured, and its structure was analyzed. The thermal behavior of DATS was investigated. The activation energy and pro‐exponential factor were calculated, E_k = 120.86 KJ/mol, A_k = 10^12.96 s^?1. The density, heat of formation, detonation pressure, and detonation velocity of DATS were first calculated. The detonation pressure and detonation velocity of DATS are P = 11.877 GPa, D = 5.617 km s^?1, which are smaller than those of 1,5‐diaminotetrazolium nitrate (DATN) (P = 33.3GPa, D = 8.77 km s^?1).     

An evaluation of nitro derivatives of cubane using ab initio and density functional theories

A novel method for judging the energy output of energetic compounds has been deduced from the conservation of energy condition. On the basis of B3LYP/6-31++G** fully optimized geometries, the enthalpy of formation, crystal density, detonation velocity and pressure for polynitrocubanes have been calculated using various theoretical methods. It has been observed that for polynitrocubanes the introduction of –NH₂ group onto the skeleton results in the destabilization of the neighboring C–C bonds on the skeleton. The C–C and C–NO₂ bonds of octanitrocubane (ONC) are stronger than those of partly nitrated cubanes, implying that the shock stability of ONC is superior to that of partly nitrated cubanes. For polynitrocubanes the calculated crystal density by the Karfunkel–Gdanitz ab initio method is within 0.07 g/cm³ of experimental crystal density, being more accurate than by the group additivity method. The detonation velocity, the detonation pressure, and the energy output all increase from tetranitrocubane to ONC. The detonation velocity and pressure of ONC are predicted to reach 9.58 km s^?1 and 60.0 Gpa, respectively. It is first indicated that the energy output for 1, 2, 3, 5, 8-pentanitrocuban is close to that of the widely used high explosive HMX and for ONC is about 80% larger than that of HMX.     

Synthesis,Structure, Chemical and Energetic Characterization of 1,3‐Dinitramino‐2‐nitroxy‐propane

The title compound, 1,3‐dinitramino‐2‐nitroxy‐propane ( 1 ) was prepared in high yield (85 %) and characterized by multinuclear NMR (¹H, ¹³C, ¹⁴N) and vibrational (IR, Raman) spectroscopy. The molecular structure in the solid state was elucidated by single crystal X‐ray diffraction. 1 crystallizes in the orthorhombic space group P_nma with a crystal density of ρ = 1.798 g cm^?3. Compound 1 melts at 166 °C and decomposes at 168 °C. The impact (7 J), friction (96 N) and electrostatic discharge sensitivities (0.6 J) were determined experimentally. The detonation parameters of 1 were calculated using a combined quantum chemical (CBS‐4M) calculation and a chemical equilibrium calculation based on the steady‐state model of detonation: Q = ?5998 kJ kg^?1, P = 339 kbar, D = 8895 m s^?1. The experimentally determined detonation velocity (fiber optic method) agrees well with the calculated values. In comparison with picric acid (PA) and nitropenta (PETN), compound 1 shows superior detonation characteristics when detonated in a confined space.     

New potential high energy density compounds: Oxadiaziridine derivatives

The -CN, -N₃, -NF₂, -NH₂, -NHNO₂, -NO₂, and -ONO₂ derivatives of oxadiaziridine were studied using B3LYP/6-311G** level of density functional theory. The gas phase heats of formation of oxadiaziridine derivatives were calculated by isodesmic reaction. All these compounds have high and positive heats of formation due to strain energies of small ring. Detonation properties were calculated via Kamlet-Jacobes equations and specific impulse. The effects of substituent groups on detonation performance were discussed. The impact sensitivity was estimated according to the “available free space per molecule in unit cell” and “energy gaps” methods. The similar conclusions were given by two different methods. The effects of substituents on impact sensitivity were discussed. According to the given estimations of detonation performance and sensitivity, some oxadiaziridine derivatives may be considered promising high energies materials.     

TATB/氟聚物PBX力学性能、结合能和爆炸性能的模拟计算

Molecular dynamics （MD） method was used to simulate 1,3,5-triamino-2,4,6-trinitrobenzene （TATB） coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB〉TATB/PVDF〉TATB/F2311〉TATB/ F2314 〉 TATB/PCTFE while the order of detonation velocity is TATB/PVDF 〈 TATB/F2311 〈 TATB/F2314 〈 TATB/PCTFE 〈TATB.     

Detonation Properties of High Explosives Containing Ammonia Borane

Ammonia borane (AB) is used as a combustion agent to improve the properties of high explosives. The detonation velocity (D_v) and detonation pressure (P) of raw high explosives and of samples containing AB were calculated and compared. The detonation properties, impact sensitivities, thermal sensitivities, and thermal decomposition characteristics of high explosives containing AB were also measured. The results indicated that when the AB content was 20 wt‐%, the optimal detonation velocity and detonation pressure were achieved. Both the detonation velocity and detonation pressure of the high explosives containing AB were clearly increased compared with those of the raw high explosives. Moreover, the detonation velocities of high explosives containing AB were 7078 to 7423 m · s^–1 and their density ranged from 1.570 to 1.589 g · cm^–3. The detonation pressure ranged from 34.5 to 37 GPa and the average heat of detonation was 6688 J · g^–1. Furthermore, the impact and thermal sensitivities were 170 cm and 613 K, respectively, whereas a slight change occurred in the thermal decomposition characteristics. These results suggest that AB can serve as a powerful combustible agent in energetic materials and improve the detonation properties and sensitivities of high explosives.     

DFT investigation on detonation properties and sensitivities of bridged triazolo[4,5-d]pyridazine based energetic materials

A series of bridged triazolo[4,5-d]pyridazine based energetic materials were optimized at B3LYP/6-311G(d, p) level of density functional theory (DFT), and their detonation properties and sensitivities were calculated. The results show that the  NN bridge/ N₃ group were beneficial to improve values of heats of formation while  NN bridge/ C(NO₂)₃ group can improve detonation properties remarkably. In view of the sensitivities, compound F2 possesses the minimum values of impact sensitivity which reveals that  NHNH bridge/ C(NO₂)₃ group will decrease the stability of the designed compounds. Take both of detonation properties and sensitivities into consideration, compounds C8, E7, E8, F8 were screened as candidates of potential energetic materials since these compounds possess similar detonation properties and sensitivities values to those of RDX. All the calculated results were except to shine lights on the design and synthesis of novel high energy density materials.     

Computational study on energetic properties of nitro derivatives of furan substituted azoles

Density functional theory has been used to investigate geometries, heats of formation (HOFs), C-NO₂ bond dissociation energies (BDEs), and relative energetic properties of nitro derivatives of azole substituted furan. HOFs for a series of molecules were calculated by using density functional theory (DFT) and Møller–Plesset (MP2) methods. The density is predicted using crystal packing calculations; all the designed compounds show density above 1.71 g/cm³. The calculated detonation velocities and detonation pressures indicate that the nitro group is very helpful for enhancing the detonation performance for the designed compounds. Thermal stabilities have been evaluated from the bond dissociation energies. Charge on the nitro group was used to assess the impact sensitivity in this study. According to the results of the calculations, tri- and tetra-nitro substituted derivatives reveal high performance with better thermal stability.