KDNBF的热分解过程及非等温反应动力学

第12卷第4期含能材料Vol. 12. No. 42004年8月ENERGETIC MATERIALSAugust, 2004文章编号:1006-9941(2004)040203-04Thermal Decomposition Processes and Non-isothermal Kinetics of KDNBFLI Yu-feng, ZHANG Tong-lai, ZHANG Jian-guoState Key Laboratory of Prevention and Control of Explosion Disaster, Beying Institute of Technology, Beiing 100081, China)Abstract: The thermal decomposition process of potassium 4, 6-dinitro-7-hydroxy-7-hydrobenzofuroxanate(KDNBF) is studied by using DSC, TG-DTG and FT-IR techniques. The results show that the solidresidue at 230 C are RCOOK, KNCO, RNO, and KNO,, and at 306 C are KNC, RCOOK and KNO,respectively. The Arrhenius parameters of the decomposition reaction are calculated using Kissinger's andOzawa-Doyle' s method, indicating that the results obtained by the two methods agree well with each otherand the Arrhenius equation of this reaction can be expressed by Ink 45 2-192600/RT.Key words: physical chemistry: KDNBF; thermal decomposition process; non-isothermal analysisCLC number: 0643. 11ocument code: A1 Introductionreplace the heavy-metal primary explosives, such as mer-cury fulminate, lead azide and lead styphnate( 2)Mercury fulminate, lead azide, lead styphnate andAs a highly sensitive material, the thermal hazardtetrazene etc. are those primary explosives of which are studies on KDNBF are both practical and fundamental. Abeing used widely since they were synthesized. However, better understanding of the thermal hazards of KDNBFall of them have their own shortages that are not suitable should improve safety in manufacture and handling operafor either military or civilian applications. For example, tions. On the thermal studies of KDNBF, Jones et all3mercury fulminate is instable and easily being pressed has done considerable work on the gaseous products ofdead", and lead styphnate is too sensitive to static elec KDNBF, but little is known on the corof the sol-tricity. What's more, the heavy metal pollutions after id residues of which will influence the igniting ability anddetonation or combustion have aroused more and more the environmental properties. the study on the thermalheavy metal free and good property primary explosives. and complemented s of KDNBF in this area is continueconcerns. Therefore, efforts should be done to develop decomposition prodPotassium salt of 4, 6-dinitrobenzofuroxan, i. e. potassiFor a reaction in the expression: A(s)B(s)+um 4, 6-dinitro-7-hydroxy-7-hydrobenzofuroxanate(KDN- C(g), the Kissingers and Ozawa-Doyle's method can beBF) is one of such primary explosives that has been used used to obtain the activation energy, E, and the pre-expo-in initiating compositions since the early 1950'sQnential factor, A, which are used to give the arrhenius eAs an environmental-friendly primary explosive, quation, without consideration of the kinetics mechanismKDNBF is very sensitive to flame. Its mechanical sensi- function. Therefore, the Kissinger's method and Ozawativity is between mercury fulminate and lead azide. It can Doyles method to calculate and analyze E, and A will albe used in many military and commercial applications to so be described in this paper.2 ExperimentalReceived date: 2003-05-08 Revised date: 2004-04-02Fundation item: Bir basic research project 000Y022.1 MaterialsBiography: LI Yu-feng, male, master caster candidate, engagedresearch of energetic materials and their applicationse-mail:leatel10@@sina.comH中国煤化工吗 e metnod repor-different crystal modifiCNMHGith potassium ion含能材料第12卷sodium salt of 4, 6-dinitrobenzofuroxan( NaDNBF). The existence of NO, and NO2 can also be detected, whichpreparation of spherical KDNBF was illustrated in detail is at 1388 cm"and 1264 cm", respectively.elsewhere. Quantitative analysis of KDNBF was con-ducted by spectrophotometry. Its purity was more than200799%. Antistatic precautions were used when manipulatingKDNBF, Conductive tablemat, samples containers, gog-gle and wrist straps were used in consideration of safety. EThe relative humidity in the room was kept above2.2 DSCA Perkin-Elmer Pyris 1 DSc analyzer was used forSC measurements. Dry, oxygen-free nitrogen was used to 15 24 100purge the DSC at 20 mL min". Heating rate analyzing10Kn-isothermal analysis, the heating rates were 2, 5, 10 andFig 1 DSC curve of KDNBF20Knple mass is about 0.5contained in sealed aluminu8922.3 TGAA Perkin-Elmer Pyris 1 TG analyzer was used for TG-DTG measurements. About 0. 5 mg of sample was held in aplatinum pan, with a flow of dry, oxygen-free nitrogen at20mL·min. The heating rate was 10 K·min2.4 FT-IRA Bruker Equinox 55 FT-IR spectrometer( KBr pel-16let)with the resolution of 4 cm was used to record the500859frared spectra of solid residue for decomposition study ofKDNBF at various temperatureFig 2 TG-DTG curves of KDNBF: solid line, TG curveAll of the equipments have been calibratedotted-dash line. DTG curve3 Results and discussion3.1 Thermal decomposition processesThe DSC and TG-DtG curves are shown in Fig. 1processes of KDNBF. As shown in Fig. 1, there are two306℃exothermic peaks in the DSC curve, one strong initialk, with another much weaker subsequent peak.Thefirst exothermic peak starts at 197C and ends at 226C400035003000250020001500with peak temperature at 216C. The IR spectrum of solwavenumber/am 1id residue at 230C was performed using FT-IR(seeFig. 3 IR spectra of the solid residues of KDNBFFig 3). The absorption at 2193 cm"indicates the existenceermin neak tarts at 239 C andstretch vibration v(一=0). At the same time, ends at中国煤化工 due at306℃the very strongorption at 1628 cm-1may be attributed was alsCNMHGFig. 3). The ab-to the asymmetric stretch vibration of vn (RCO?). The sorption at 2193i is replaced by the absorption at第4期LI Yu feng, et al Thermal Decomposition Processes and Non-isothermal Kinetics of KDNBF2171 cm which indicates the existence of -N=c 3. 2 Kinetics parameters of non-isothermaland the disappearance of -N=C=0. The very strongabsorption at 1628 cm" of v. (RCO2)andAs mentioned above on the basis of dsc data, kinetbsorption at 1388 cm" of v, NO, )still exists but the ics parameters for thermal decompositions of KdNBFstrong absorption at 1264cm-'of v. (No disappeare. could be obtained by Kissinger'g0)and Ozawa-Doyle'sA third exothermic peak, with peak temperatureethod[11, 12. The kinetic analysis that follows was based374C also appears in static air but disappears with nitro- on the first exothermic peakgen or helium as purge gas. This indicates that the thirdArrhenius parameters for the thermal decompositionexothermic peak is the oxidization process of the solid res- of KDNBF, from this study and elsewhere are shown intable IAccording to Fig. 2, there was still 22% residue leftTable 1 E. and InA for first-step thermalat 800C, which is a substantial solid residue comparingdecomposition of KDNBFwith the decomposition of K(NTO)(H, 0)07, KPA 7IethodE./kJ·molh(As1)K2(TNR)(H,0)8)and KH(TNR)(H, 0)[9. For exKissinger( this work)89.itzawa Doyle( this workdues of K,(TNR)(H20) and KH( TNR)(H,0)wereASTM E698 3J181±1042.7±0.1ry little, which were 11% and 2ASTM E1641(03)190±6In a word, the thermal decomposition processes ofDSC dynamic(4)179canaccording to our above work and the work reported byThe values about E, and InA through this work are aJones et al 3, who paid much more attention on the de- little higher than these in literature [3, 13, 14].This cantermination of its gaseous products:e different test conditions and the physiKDNBF--RCOOK+KNCO+KNO]+RNO 2+C02+N20+ H20+(CN)2 cal properties such as granularity etc. of KDNBF obtainedRCOOK+KNC KNO3+ cO2It is obvious that the thermal decomposition of KDNTherefore, the Arrehnius equation can be expressedBF is a complex process according to the DSC, TG-DTG with unweighted average of Ea and InA obtained from thisand the FT-IR analysis. There are no N-C-o bondsas followsKDNBF, therefore the form of KNCO requires the breaklnk=45.2-192600/RTing and forming of several chemical bonds. Similarlythere are no C-o bonds on the original molecule, so the 4 Conclusionformation of RCO, K should be a multi-step process(1) The thermal decomposition process of KDNBFIt can be seen no endothermic peaks from the DSC results in the formation of RCOOK, KNCO, RNO2, KNO,curve, which usually owing to the melting, thawing of the at 230 and KNC, RCooK and KNO, at 306Csample or dehydration of the sample. This in fact is one(2) The Arrehnius equation can be expressed as Inkof the differences between primary explosives and high ex- =45.2-192600/RT, using Kissingers and OzawaDoyle's methodmary explosives contain no endothermic stage but the exo-thermic peak is very sharp. However, it is may be theReferencesmask from the initial exotherm that causes no endothermic[1] Spear R J, Norris W P. Structure and propertieshad menpotassium hydroxide dinitrobenzofuroxan adduct (K中国煤化工[J], Propellant, explo-CNMHGTechnology of Primary206含能材料第12卷plosives[M]. Beijing: Beijing Institute of Technology [8] LI Yu-feng, ZHANG Tong-lai, ZHANG Jian-guo, et alPress, 1997(in Chinese)Preparation, crystal structure and thermal decomposition[3] Jones D E G, Lightfoot P D, Fouchard R C, Kwok Qmechanism of [K,(TNR)(H,0).[J].Chinese.InTurcotte A M, Ridley W. Hazard characterization of KD.org.Chem,2003,19(8):861NBF using a variety of different techniques[J].Thermo[9] LI Yu-feng, ZHANG Tong-lai, ZHANG Jian-guo, et alchim. Acta,2002,384:5Preparation, molecular structure and thermal decomposi[4] Piechowics T. Preparation of 4, 6-dinitrobenzofuroxan-an mechanism of KH(TNR)(H, 0)][J]. Acta Himi.useful initiating explosives[P]. France Patent Nca sinica,2003,61(7):10201579799,1968.[Chem. Abstr.1969,71,31790.][10] Jones DEG, Feng H T, Fouchard R C. Kinetic studies of[5]. LI Yufeng, ZHANG Tong-lai, MIAO Yan-ling, et al.Athe thermal decomposition of KDNBF, a primer for explenew way to synthesize spherical KDNBF[J]. Chinese Jsives[J]. J. Therm. Anal. Cal., 2000, 60:917Explosives Propellants, 2003, 26(3): 53[11] Kissinger H E. Reaction kinetics on differential thermal[6] Brill T B, ZHANG Tong-lai, Tappan B C.Thermal de-analysis[J]. Anal. Chem., 1957, 29(11):1702als 74. Volatile metal iso- [12] Ozawa T. A new method of analyzing thermo-gravimetriccyanates from flash pyrolysis metal-NTO and metal-picratedata[J]. BulL. Chem. Soc. Jpn, 1965, 38(11)saltsandanapplicationhypothesisJ].combust.Flamel881.[13] Doyle C D J Kinetic analysis of thermo-gravimetric data[7] ZHANG Tong-lai, HU Rong-zu, LIANG Yan-jun, et al[J.J. Appl. Polymer Sci., 1961, 5: 285Preparation and thermal decomposition mechanism of al- [14]Whelan D J, Spear R J, Read R W. Thermal study ofkaline metal(Li, Na and K)salts of 3-nitro-1, 2, 4-triza-KDNBF[J]. Thermochim. Acta, 1984, 80:149ol-5-one[].J.Them,Anal.,1993,39:827KDNBF的热分解过程及非等温反应动力学李玉锋,张同来,张建国(北京理工大学爆炸灾害预防与控制国家重点实验室,北京10001)摘要:利用DSC, TG-DTG及FIR技术对46二硝基7羟基7氢化苯并氧化呋咱钾(KDNF)的热分解过程进行了研究。结果表明,230℃时固体残渣中含有 RCOOK,KNCO,RNO2KNO3,而在306℃时则含有KNC, RCOOK及KNO3。利用 Kissinger法与 Ozawa-Doyle法对l的热分解过程进行了动力学计算。两种方法所得结果互相吻合结合本文及文献结果,Art方程可表达为:lnk=45.2-19260/RT。关键词:物理化学; KDNBF;热分解机理;非等温分析法中图分类号:0643.11文献标识码:A中国煤化工CNMHG