張 馳, 陳 沫, 陳 湘, 張 聰, 宋紀(jì)蓉,2, 馬海霞

(1. 西北大學(xué)化工學(xué)院, 陜西 西安 710069; 2. 北京故宮博物院文?？萍疾? 北京 100080)

1 引 言

高氮含能化合物是近年來發(fā)展起來的并具有良好應(yīng)用前景的高能量密度材料(HEDM),它具有很高的正生成焓,感度較低,熱穩(wěn)定性好,閃點(diǎn)溫度高,且分子結(jié)構(gòu)中的高氮低碳?xì)浜渴蛊渚哂休^高的密度,也更容易達(dá)到氧平衡[1-2]。四嗪類高氮化合物分子結(jié)構(gòu)中含有較多的N—N和C—N鍵,四嗪環(huán)的含氮量高達(dá)68.3%,具有能量高、熱穩(wěn)定性好、特征信號(hào)低、燃燒無殘?jiān)盁o污染等優(yōu)點(diǎn),廣泛應(yīng)用于推進(jìn)劑、新型高能鈍感炸藥和煙火劑等含能材料領(lǐng)域[3-4]。而稠環(huán)含能化合物一般都具有較高的密度和能量,是目前高能量密度材料重要研究方向之一[5-6]。3-肼基-6-(3,5-二甲基吡唑)-s-四嗪可以發(fā)生成環(huán)反應(yīng)形成稠環(huán)類四嗪含能化合物[7],如s-四嗪并三唑的衍生物1,2,4-三唑[4,3-b]并s-四嗪(TTZ)、6-氨基-1,2,4-三唑[4,3-b]并s-四嗪(ATZ)和3,6-二氨基-1,2,4-三唑[4,3-b]并s-四嗪(AATZ)。其后,研究者合成了許多稠環(huán)類四嗪衍生物[8-14],但有關(guān)該類化合物的研究大多集中在該類物質(zhì)的制備及機(jī)理方面的研究,而有關(guān)性能研究相對(duì)較少。

基于此,本研究選取了一系列五元氮雜環(huán)與母體1,2,4,5-四嗪連接組成稠環(huán)化合物,設(shè)計(jì)了14種1,2,4,5-四嗪衍生物,在wB97/6-31+G**水平下獲得此類化合物的穩(wěn)定構(gòu)型,在此基礎(chǔ)上計(jì)算了其生成焓及爆轟性能,從理論上研究五元氮雜環(huán)作為取代基構(gòu)成的稠環(huán)化合物對(duì)1,2,4,5-四嗪的影響,考察性能與結(jié)構(gòu)之間的對(duì)應(yīng)關(guān)系。

2 計(jì)算方法

運(yùn)用DFT方法,在B3LYP/(6-31G*,6-311G*,6-31+G*,6-31G**,6-311G**,6-31+G**,6-311++G**,cc-pVDZ,cc-pVTZ)水平下計(jì)算分析1,2,4,5-四嗪、3,6-二氨基-1,2,4,5-四嗪(DAT)、3,6-二肼基-1,2,4,5-四嗪(DHT)和3,6-二疊氮基-1,2,4,5-四嗪(DIAT)4種化合物的生成焓,通過與實(shí)驗(yàn)值[15]進(jìn)行對(duì)比擬合,在B3LYP/6-31+G**水平下計(jì)算的結(jié)果與實(shí)驗(yàn)值線性相關(guān)性最好,達(dá)到0.9863,因此選擇基組6-31+G**和不同方法(B3PW91,M05,M05-2X,M06,M06-2X,wB97)組合計(jì)算上述4種化合物生成焓,通過與實(shí)驗(yàn)值進(jìn)行對(duì)比擬合,在wB97/6-31+G**水平下計(jì)算的結(jié)果與實(shí)驗(yàn)值線性相關(guān)性最好,達(dá)到0.9896,因此在wB97/6-31+G**水平下對(duì)所設(shè)計(jì)的14種1,2,4,5-四嗪衍生物的幾何結(jié)構(gòu)進(jìn)行全優(yōu)化,經(jīng)振動(dòng)頻率分析表明優(yōu)化構(gòu)型為勢(shì)能面上極小點(diǎn)(無虛頻),得到的熱力學(xué)數(shù)據(jù)采用原子化方案(atomization scheme)[16-20]預(yù)測(cè)目標(biāo)化合物的標(biāo)準(zhǔn)生成焓。具體方法是將分子分解為原子:

CaHbOcNd(g)→aC(g)+bH(g)+cO(g)+dN(g)

(1)

則該反應(yīng)在298K時(shí)的標(biāo)準(zhǔn)反應(yīng)焓ΔH298由下式計(jì)算:

ΔH298=ΣΔHf,P-ΣΔHf,R

=aΔHf,C+bΔHf,H+cΔHf,O+dΔHf,N-ΔHf,CaHbOcNd

(2)

式中,ΔHf,R和ΔHf,p分別表示反應(yīng)物和生成物在298 K的標(biāo)準(zhǔn)生成焓,kJ·mol-1; ΔHf,C、ΔHf,H、ΔHf,O和ΔHf,N分別為原子C、H、O和N在298 K的標(biāo)準(zhǔn)生成焓,可從手冊(cè)[21]中查得; ΔHf,CaHbOcNd為分子CaHbOcNd在298 K的標(biāo)準(zhǔn)生成焓,為待求項(xiàng)。同時(shí)存在下列關(guān)系式:

ΔH298=ΔE298+Δ(pV)

=ΔE0+ΔEZPE+ΔET+ΔnRT

=E0,C+E0,H+E0,O+E0,N-E0,CaHbOcNd-

EZPE,CaHbOcNd-ΔET,CaHbOcNd+ΔnRT

(3)

式中,E0,C、E0,H、E0,O、E0,N和E0,CaHbOcNd分別為wB97/6-31+G**水平下計(jì)算得到的原子C、H、O、N和分子CaHbOcNd在0 K的總能量,a.u.;EZPE,CaHbOcNd和ΔET,CaHbOcNd分別為分子CaHbOcNd的零點(diǎn)能和熱校正值,a.u.,可從振動(dòng)分析獲得的熱力學(xué)數(shù)據(jù)得到,對(duì)原子而言,EZPE和ΔET項(xiàng)均為0; Δn表示氣體產(chǎn)物和反應(yīng)物的物質(zhì)的量之差,mol;R是氣體常數(shù),8.314 J·mol-1·K-1;T表示絕對(duì)溫度,K。綜合上式,化合物CaHbOcNd在298 K的標(biāo)準(zhǔn)生成焓ΔHf,CaHbOcNd即可求得。

運(yùn)用半經(jīng)驗(yàn)K-J方程[22-25]估算其爆速(D)、爆壓(p)值:

D=Φ0.5(1.011+1.312ρ)

(4)

p=1.558Φρ2

(5)

(6)

研究中所有化合物密度均采用摩爾體積法(ρ=M/Vm)計(jì)算得到,其中M為化合物的摩爾質(zhì)量,Vm為化合物的摩爾體積,是在穩(wěn)定構(gòu)型下,基于0.001 e·bohr-3等電子密度面所包圍的體積空間,用Monte-Carlo方法對(duì)每一個(gè)優(yōu)化的穩(wěn)定構(gòu)型進(jìn)行了100次單點(diǎn)計(jì)算取其平均值求得。所有計(jì)算使用Gaussian09[26]量子化學(xué)軟件包在wB97/6-31+G**水平下完成。

parameterscomponentsofCaHbOcNdc≥2a+b22a+b2>c≥b2b2>cNb+2c+2d4Mb+2c+2d4Mb+d2MM—4Mb+2c+2d56d+88c-8bb+2c+2d2b+28d+32cb+dQ28.9b+47.04a+0.239ΔHfM28.9b+94.05c2-b4()+0.239ΔHfM57.8c+0.239ΔHfM

Note:Mis the molar mass of a compound, ΔHfis the calculated heat of formation.

3 結(jié)果與討論

3.1 幾何結(jié)構(gòu)

在wB97/6-31+G**水平下對(duì)1,2,4,5-四嗪衍生物進(jìn)行幾何結(jié)構(gòu)全優(yōu)化,圖1列出了其優(yōu)化結(jié)構(gòu)圖,標(biāo)注了部分優(yōu)化幾何參數(shù)(鍵長(zhǎng)、鍵角)。計(jì)算結(jié)果表明,與1,2,4,5-四嗪相比四嗪環(huán)上N(1)—N(2)鍵長(zhǎng)均縮短,除了T2靠近五元環(huán)一側(cè)的N(4)—N(5)鍵長(zhǎng),其余化合物的鍵長(zhǎng)均增加,雙環(huán)取代更明顯; 單環(huán)取代四嗪衍生物C(3)—N(4)鍵長(zhǎng)均縮短,其他C—N鍵長(zhǎng)均增加,雙環(huán)取代四嗪衍生物C—N鍵長(zhǎng)均增加,且大部分五元環(huán)的C—N鍵長(zhǎng)小于未成五元環(huán)的; 同分異構(gòu)體化合物中,五元環(huán)上N原子位置不同,使四嗪環(huán)的上的鍵長(zhǎng)和鍵角不同,但數(shù)值非常接近,因此N原子位置對(duì)四嗪環(huán)的鍵長(zhǎng)和鍵角影響較小; 除了衍生物T1和T12,其余化合物均不共面,說明隨著N原子數(shù)量的增加,稠環(huán)類四嗪衍生物的共面性反而降低。

圖11,2,4,5-四嗪衍生物的分子優(yōu)化結(jié)構(gòu)圖及部分鍵長(zhǎng)(nm)和鍵角(°)

Fig.1Optimized molecular structures for the 1,2,4,5-tetrazine derivatives along with their selected bond lengths(nm) and bond angles(°)

3.2 生成焓

在wB97/6-31+G**水平下采用原子化方案估算稠環(huán)四嗪衍生物及傳統(tǒng)含能材料RDX和HMX的生成焓,表2列出了目標(biāo)化合物的總能量(E0)、零點(diǎn)能(EZPE)、N原子數(shù)、溫度校正值(HT)及生成焓(ΔHf)。

計(jì)算結(jié)果表明,所有1,2,4,5-四嗪衍生物生成焓均大于傳統(tǒng)含能材料RDX和HMX,具有高正生成焓,其中最高的生成焓值為1122.53 kJ·mol-1。所有化合物的生成焓均比未取代的1,2,4,5-四嗪生成焓高,雙環(huán)取代四嗪衍生物生成焓普遍大于相應(yīng)單環(huán)取代的,幅度為140～280 kJ·mol-1。單環(huán)取代中,化合物T2和T3,T4、T5和T6分別互為同分異構(gòu)體,T2的生成焓高于T3,T4的生成焓高于T5和T6,是因?yàn)門2中的N—N鍵數(shù)量多于T3,T4中的N—N鍵數(shù)量多于T5和T6,雙環(huán)取代(T22、T42)和單環(huán)取代一致,結(jié)果表明,N—N鍵有助于增加1,2,4,5-四嗪衍生物的生成焓。

表2均四嗪衍生物及HMX和RDX的總能量、零點(diǎn)能、溫度校正值和生成焓

Table2CalculatedE0,EZPE,HTand ΔHfof s-tetrazine derivatives together with HMX and RDX

compd.formulaE0/a.u.EZPE/a.u.HT/a.u.numberofNΔHf/kJ·mol-1TC2H2N4-296.28570.05270.00514527.49T1C5H4N4-411.80010.09480.00674606.69T2C4H5N5-428.98800.10610.00725744.06T3C4H5N5-429.01810.10590.00735664.85T4C3H4N6-445.01060.09390.00706825.63T5C3H4N6-445.04780.09440.00706729.00T6C3H4N6-445.03610.09420.00706759.44T7C2H3N7-461.05650.08190.00697846.05T12C8H6N4-527.29020.13590.00894749.08T22C6H8N6-561.69950.16010.00916937.70T32C6H8N6-561.75080.15970.00956802.88T42C4H6N8-593.74020.13580.008981112.41T52C4H6N8-593.80790.13580.00948936.04T62C4H6N8-593.80230.13720.00878952.80T72C2H4N10-625.84420.11190.0087101122.53RDXC3H6N6O6-897.35320.14700.01346244.21HMXC4H8N8O8-1196.47500.19720.01788317.19

Note:E0is total energy ,EZPEis zero point energy,HTis correction of temperature.

選取相同N原子數(shù)中生成焓最大的化合物,對(duì)其總能量(E0)和生成焓(ΔHf)與N原子數(shù)的關(guān)系作線性擬合,由圖2和圖3可知,不論是單環(huán)取代還是雙環(huán)取代,隨著N原子數(shù)的增加,分子總能量逐漸降低,且具有很好的線性關(guān)系,生成焓則逐漸增大,表明N原子數(shù)的增加有助于提升1,2,4,5-四嗪衍生物的生成焓。綜上所述,N—N鍵及N原子數(shù)的增加在提升1,2,4,5-四嗪衍生物的生成焓方面起了重要的作用。

圖2總能量(E0)與N原子數(shù)的關(guān)系

Fig.2The relationship ofE0and N atom numbers

圖3生成焓(ΔHf)與N原子數(shù)的關(guān)系

Fig.3The relationship of ΔHfand N atom numbers

3.3 前線軌道能量

分子軌道理論表明,化合物的穩(wěn)定性與其分子軌道能量有關(guān),最高占據(jù)軌道能量(EHOMO)越低,最低空軌道能量(ELUMO)越高,則其分子軌道能級(jí)差(ΔELUMO-HOMO=ELUMO-EHOMO)越大,化合物就越穩(wěn)定。運(yùn)用量子化學(xué)的方法計(jì)算了1,2,4,5-四嗪衍生物的EHOMO及ELUMO,進(jìn)一步分析得到ΔELUMO-HOMO,列于表3。計(jì)算結(jié)果表明,單環(huán)取代衍生物的分子軌道能級(jí)差與T比較均減小,雙環(huán)取代衍生物除了T12和T32,其它分子軌道能級(jí)差與T比較均增大,T62的分子軌道能級(jí)差在所有體系中較高,使電子躍遷幾率降低,預(yù)示其反應(yīng)活性最低,最穩(wěn)定。

表3目標(biāo)化合物的前線軌道能量

Table3CalculatedEHOMO,ELUMO和ΔELUMO-HOMOof the title compounds

a.u.

3.4 爆轟性能

爆速和爆壓是研究爆轟性能的兩個(gè)較為重要的參數(shù),本文在wB97/6-31+G**水平下預(yù)測(cè)了1,2,4,5-四嗪衍生物及HMX和RDX的爆速(D)和爆壓(p),如表4所示。無論是單環(huán)取代還是雙環(huán)取代的衍生物,D和p都是隨著體系中N原子數(shù)的增加而增加; 除了單環(huán)取代的T1、T2、T3及雙環(huán)取代的T12、T22、T32,其他衍生物的密度、爆速和爆壓均高于未取代的T; 帶有同一種環(huán)單取代和雙取代,對(duì)D和p的影響較小,且有些單環(huán)取代衍生物的D和p略偏高,如單環(huán)取代化合物T1、T2和T3比相應(yīng)雙環(huán)取代的T12、T22、T32高,說明稠環(huán)四嗪衍生物D和p與所含N原子數(shù)關(guān)系較大,與環(huán)的個(gè)數(shù)關(guān)系較小?；衔颰7和T72的D接近于傳統(tǒng)含能材料RDX,p略低于RDX,ρ則遠(yuǎn)遠(yuǎn)小于RDX,從能量角度來看,提高四嗪衍生物的密度,其爆轟性能也將提高,所以T7和T72可以作為潛在的含能材料。

1,2,4,5-四嗪衍生物的D和p與N原子數(shù)的線性擬合關(guān)系如圖4所示,圖4a與圖4c為單環(huán)取代四嗪衍生物的D和p與N原子數(shù)的線性關(guān)系,圖4b與圖4d為雙環(huán)取代四嗪衍生物的D和p與N原子數(shù)的線性關(guān)系。從圖4可以看出,無論是單環(huán)取代還是雙環(huán)取代,1,2,4,5-四嗪衍生物的D和p與N原子數(shù)均有很好的線性關(guān)系,相關(guān)系數(shù)r分別為0.987、0.998(單取代D、p)和0.988、0.996(雙取代D、p)。

a. D, one ring substituted

b. D, double rings substituted

c. p, one ring substituted

d. p, double rings substituted

圖4爆速(D)及爆壓(p)與氮原子數(shù)目的關(guān)系

Fig.4The relationship ofDandpwith N atom numbers

表4目標(biāo)化合物及RDX和HMX的摩爾質(zhì)量、平均摩爾體積、理論密度、爆熱、爆速和爆壓

Table4PredictedM,V,ρ,Q,Dandpof the title molecules together with RDX and HMX

compd.V/cm3·mol-1M/g·mol-1ρ/g·cm-3Q/J·g-1D/km·s-1p/GPaT55.99182.0281.471536.9177.3621.08T183.833120.0441.431207.8856.1114.29T285.218123.0551.441445.1357.0919.33T385.345123.0551.441291.2916.9018.27T482.443124.0501.501590.6977.7423.64T584.790124.0501.461404.5257.3721.05T683.456124.0501.491463.1727.5422.37T780.086125.0451.561617.0668.2227.40T12110.857158.0591.431132.6775.5911.94T22115.064164.0811.431365.8516.9018.21T32115.618164.0811.421169.4736.6116.62T42106.731166.0721.561600.9128.0526.25T52106.707166.0721.561347.0927.7124.08T62106.296166.0721.561371.2117.7424.30T72103.365168.0621.631596.3438.6531.24RDX129.53222.041.71(1.82[27])1679.208.76(8.75[27])33.05(34.00[27])HMX162.87296.051.82(1.91[27])1672.409.11(9.10[27])37.08(39.00[27])

Note:Mis molar mass,Vis average molar volume,ρis theoretical density,Qis explosion heat,Dis detonation velocity andpis detonation pressure.

3.5 熱力學(xué)性質(zhì)

運(yùn)用量子化學(xué)計(jì)算的方法,以分子統(tǒng)計(jì)熱力學(xué)為基礎(chǔ),計(jì)算了稠環(huán)類1,2,4,5-四嗪衍生物在200～800K的熱力學(xué)性質(zhì),即標(biāo)準(zhǔn)摩爾熱容(Cp,m)、標(biāo)準(zhǔn)摩爾熵(Sm)和標(biāo)準(zhǔn)摩爾焓(Hm),列于表5。由表5可以看出,Cp,m、Sm及Hm均隨T的升高而增加,其中Cp,m和Sm增大的比例均隨著T的升高而逐步減小,而Hm增大的比例則隨著T的升高而逐步增大。在T較低時(shí),分子的轉(zhuǎn)動(dòng)及平動(dòng)對(duì)Cp,m、Sm和Hm貢獻(xiàn)相對(duì)較大; 但是隨著溫度升高到一定程度后,分子的振動(dòng)增強(qiáng),對(duì)Cp,m、Sm和Hm貢獻(xiàn)大,而導(dǎo)致Cp,m、Sm和Hm值增加。在同一T下,隨著N原子數(shù)的增加,Cp,m、Sm及Hm與溫度之間沒有線性的變化; 同時(shí),雙取代環(huán)的Cp,m、Sm和Hm明顯大于相應(yīng)的單取代環(huán)的,說明取代環(huán)的增加有利于這些熱力學(xué)函數(shù)值的增加。

表5目標(biāo)化合物200～800 K時(shí)的Cp,m、Sm和Hm

Table5CalculatedCp,m,SmandHmat 200～800 K for the title molecules

T1T12TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 69.10289.168.83200 94.96321.5011.16273.15 94.54314.3914.80273.15 131.59356.4519.43298.15103.48323.0617.28298.15144.24368.5322.88400137.82358.3829.61400192.36417.8040.08500165.98392.2744.85500231.58465.1061.35600188.37424.5962.61600262.74510.1986.13700206.04455.0082.36700287.40552.61113.68800220.14483.47103.70800307.16592.32143.44T2T22TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 74.68296.559.53200 97.98324.1611.38273.15100.80323.6215.94273.15136.76360.3219.94298.15110.06332.8518.57298.15150.58372.8923.53400146.04370.3231.65400204.33424.8141.66500175.90406.2347.80500248.61475.3464.38600199.80440.5066.63600283.81523.9091.07700218.79472.7787.60700311.69569.83120.90800234.08503.03110.26800334.13612.96153.23

續(xù)表5

Table5continued

T3T32TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 76.23296.609.58200 101.65329.8711.93273.15102.76324.2316.12273.15140.49367.2020.76298.15111.99333.6318.80298.15154.21380.0924.45400147.61371.6232.06400207.22432.9842.91500177.07407.8448.35500250.74484.0765.89600200.67442.2967.28600285.32532.9692.76700219.44474.6888.32700312.74579.08122.71800234.55505.00111.05800334.81622.33155.13T4T42TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 72.99296.019.49200 95.30322.4911.29273.1597.41322.3115.70273.15130.60357.3219.53298.15106.05331.2118.2298.15143.09369.3022.95400139.59367.1530.79400191.50418.2540.04500167.33401.3946.18500231.31465.4361.25600189.45433.9364.07600262.88510.5086.03700206.93464.5083.92700287.74552.96113.61800220.89493.08105.34800307.58592.73143.40T5T52TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 73.16295.339.44200 100.87334.7012.28273.1597.64321.7015.68273.15135.22371.1520.90298.15106.22330.6218.23298.15147.26383.5124.43400139.46366.5830.77400193.93433.4441.85500167.00400.7646.14500232.54481.0163.24600189.02433.2363.99600263.37526.2588.10700206.47463.7383.79700287.79568.75115.70800220.43492.24105.16800307.36608.50145.49T6T62TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 73.00296.149.49200 93.30322.4411.15273.1597.36322.4415.71273.15127.84356.5219.22298.15105.94331.3418.25298.15140.15368.2522.56400139.26367.2230.77400188.30416.2939.34500166.90401.3646.13500228.31462.7660.23600189.00433.8363.97600260.23507.3284.73700206.50464.3383.77700285.46549.41112.06800220.49492.85105.15800305.64588.89141.65T7T72TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1TCp,m/J·mol-1·K-1Sm/J·mol-1·K-1Hm/kJ·mol-1200 72.12294.079.36200 93.42323.3311.37273.1595.15319.9215.47273.15125.33357.1119.35298.15103.12328.5917.95298.15136.45368.5622.62400133.81363.2830.05400179.25414.7838.75500159.11395.9544.74500214.32458.6858.49600179.27426.8261.70600242.03500.3181.37700195.13455.6980.45700263.70539.31106.70800207.71482.60100.62800280.80575.68133.95

Note:Cp,mis standard molar heat capacity,Smis standard molar entropy andHmis standard molar enthalpy.

4 結(jié) 論

利用wB97/6-31+G**方法對(duì)稠環(huán)類1,2,4,5-四嗪衍生物的幾何結(jié)構(gòu)、前線軌道能量、生成焓、爆轟性能及熱力學(xué)性質(zhì)進(jìn)行計(jì)算研究。

(1) 計(jì)算結(jié)果表明,雙環(huán)取代四嗪衍生物生成焓普遍大于相應(yīng)單環(huán)取代的,N—N鍵及N原子數(shù)的增加有助于提升1,2,4,5-四嗪衍生物的生成焓。

(2) 爆轟性能結(jié)果表明,稠環(huán)四嗪衍生物D和p主要與所含N原子數(shù)有關(guān),與環(huán)的個(gè)數(shù)關(guān)系較小,且D和p與N原子數(shù)均有良好的一次線性相關(guān)關(guān)系。

(3) 熱容Cp,m、熵Sm及焓Hm均隨著T的升高而增加,Cp,m和Sm增大的比例均隨著T的升高而逐步減小,而Hm增大的比例則隨著T的升高而逐步增大。

(4) 化合物T7和T72的爆速接近于傳統(tǒng)含能材料RDX,爆壓略低于RDX,可以作為備選的HEDM。

致謝感謝臨沂大學(xué)化學(xué)化工學(xué)院夏其英教授在Gaussian09計(jì)算中提供的幫助。

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