Indian Journal of Engineering & Materials Sciences Vol. 12, April 2005, pp. 158-164

Correlations for predicting detonation temperature of pure and mixed CNO and CHNO

M H Keshavarz Department of Chemistry, Malek-ashtar University of Technology, Shahin-shahr P.O. Box 83145/115, Islamic Republic of Iran Received 25 May 2004; accepted 10 January 2005

In this paper, detonation temperature of CNO and CHNO explosives is evaluated by the base of atomic composition and heat of formation. It is shown here how only atomic composition and condensed phase heat of formation of CNO and CHNO explosives are sufficient for reliable prediction of detonation temperature as compared to complicated computer codes. New correlations are introduced so that they can easily be applied for determining detonation temperature via specified different pathways of decomposition of explosives. Calculated detonation temperatures by this procedure for both pure and formulations show good agreement with respect to measured and the BKWS-EOS predictions of detonation temperatures. IPC Code: C06B 25/00

The detonation parameters such as heat of detonation, Kelvin and hundreds of kbar, as well as at much lower detonation temperature, detonation velocity and temperatures and pressures obtained during expansion detonation pressure are a variety of performance of the reaction products. Different computer codes parameters for measuring the effectiveness of such as BKW1 and RUBY2 and latter's offspring different explosives. When an explosive is initiated to TIGER3, CHEQ4, and CHEETAH5 assume all of the detonation, a detonation wave has traversed through chemical equations for all possible species in the its medium so that the hot gases and solid residues left reaction product gases and solving these with thermo- behind continue to exert pressure. Since detonation chemical analogues. They can also estimate the reaction of an explosive is extremely fast, the heat isentropic expansion having the equilibrium energy liberated by detonation will raise the temperature of and gas quantities along with the Rankine-Hugoniot gases, which will in turn cause them to expand and jump equations. For example CHEETAH, a C version work on surroundings. Most of the work of an of the FORTRAN equilibrium code TIGER, is an explosive in detonation is performed by the equilibrium thermochemical code used to estimate detonation reaction products. detonation parameters for explosives, as well as parameters other conditions such as a constant volume Typical detonation products of high explosives explosion. The detonation parameters can usually be with the elements carbon, hydrogen, nitrogen and calculated by a computer code when the heat of oxygen at high pressures (p~1-100 GPa) and formation and the density of the explosive substance temperatures (T~1000-5000 K) simultaneously are are known and the equation of state (EOS) is CO, N2, CO2, H2O, and solid carbon. Releasing a assumed. There are several forms of EOSs such as large amount of energy and complex chemical Becker-Kistiakosky-Wilson (BKW)6, the Jacobs- reactions are initiated to sustain the detonation Cowperthwaite-Zwisler (JCZ)7,8, Kihara-Hikita- process. The application of the hydrodynamic theory Tanaka (KHT)9, Exp-610 and Lennard-Jones- for calculating the detonation properties requires Denvoshire (LJD)11. Of different EOSs, the BKW- knowledge of the equation of state of the system that EOS is used extensively to calculate detonation can accurately reflect the thermodynamic properties properties1. The BKWC-EOS5, BKWR-EOS12 and of multicomponent mixtures at several thousand BKWS-EOS13 are three different parameterizations of the BKW-EOS so that BKWS-EOS is one of the best ______E-mail: [email protected]; [email protected] EOSs for predicting detonation temperatures. KESHAVARZ: PREDICTION OF DETONATION TEMPERATURE OF CNO AND CHNO 159

Predicting fairly accurate data, by simple empirical interacting with a detector can be used for measuring methods, are highly desired for calculating the various detonation temperatures. Since measurements in detonation parameters of explosives. There is a porous systems include the effects of shocked air or continuing need in the field of explosives for reliable perhaps low density explosive material jetting into predictions of detonation parameters. Especially voids rather than the brightness of the pure detonation knowledge of the detonation temperature is important products, void free systems such as liquid explosives or because it is difficult to measure accurately. This single crystal systems may be believed to be more study had as its original purpose to develop a simple accurate. Estimated absolute accuracies are ±100 K for reliable method for calculating detonation liquid explosives and ±200 K for solid explosives32. temperatures of high explosives with the elements Detonation temperature is maximum temperature carbon, hydrogen, oxygen and nitrogen as compared that can be obtained by assuming that heat of to complex computer codes that is usually used to decomposition of explosive is used entirely to heat the compute detonation parameters. The purpose of this products. Since decomposition reaction is very fast, it work was to correlate detonation temperature with the can be assumed that energy released is completely explosive's elemental composition and condensed transferred to detonation products during a very short phase heat of formation of the explosive. This work time. The approximate detonation temperature can be shows useful applications of derived correlations to obtained under adiabatic conditions from molar heat both pure and mixed explosives. The calculated capacities of detonation products and heat of detonation temperature will compare with measured detonation. Some pathways for ideal and less ideal and computed results of the BKWS-EOS. It should explosives are recently suggested20 which can be be noted that predicted results are comparable with given for CNO and CHNO explosives as follows: outputs of complex computer codes and the accuracy is not necessarily enhanced by greater complexity. da≤ Furthermore, an important interesting observation of cb⎛⎞ this work is that much simpler equations could be NCOC(s)H22++−+dad() ⎜⎟ written for desk calculation of detonation temperature, 22⎝⎠ with about the same reliability as one might attach to … (1a) the more complex computer output. d>a and Correlations of Detonation Temperatures b/2 ≥d-a Though detonation parameters may be measured experimentally or calculated from theory, theoretical cb⎛⎞ NCOC(s)H22++−+dad() ⎜⎟ calculations are more convenient and reduce the costs 22⎝⎠ associated with synthesis, test and evaluation of the materials. Numerous studies have been developed for … (1b) predicting the Chapman-Jouguet (C-J) detonation d>a+b/2 pressures and velocities of pure or mixture of 14-30 CaHbNcOd and different classes of explosives . To compare with d ≤ 2a+b/2 equilibrium calculations, detonation velocities are measured at various charge diameters and cb⎛⎞ ⎛ b ⎞ Nad22++−+⎜⎟HO ⎜ 2 ⎟ CO extrapolated to an "infinite diameter". Detonation 22⎝⎠ ⎝ 2 ⎠ velocities can typically be measured to within a few percent, meanwhile the detonation pressures ⎛⎞b +−−⎜⎟da CO2 … (1c) determined by indirect method span a range of 10- ⎝⎠2 20% that non-equilibrium effects in reaction zones may contribute to large uncertainty31. If the d>2a+b/2 measurement is taken behind the von Neumann spike cb2 db− and in front of C-J plane, the measured pressures in ⎛⎞ ⎛ ⎞ NHOCO22+++−⎜⎟aa 2 ⎜ ⎟ O 2 this situation may be higher than equilibrium 22⎝⎠ ⎝ 4 ⎠ calculations. The brightness of the detonation front … (1d) 160 INDIAN J. ENG. MATER. SCI., APRIL 2005

To obtain reliable correlations for predicting In the definition of the parameter of ΔT, Td is detonation temperature, experimental detonation detonation temperature in K and ΔHf is condensed temperatures were used to optimize the correlations. heat of formation of explosive in kJ/mol. The glossary Optimized correlations corresponding to Eqs (1a)- of compounds is given in Appendix A. Detonation (1d) can also be given as: temperature estimated by this method for many different underoxidized and overoxidized CNO and Δ−Hdf 529.4 CHNO explosives are given in Table 1 and compared Δ=T 10.95×− 10−−−333ab 0.1132 +×−× 13.35 10 c 99.1 10 dwith corresponding BKWS-EOS as well as the … (2a) measured values. As indicated in Table 1, the new hand calculated detonation temperature shows surprisingly very good agreement with experimental Δ−Hadf 943.4 + 1229.5 Δ=T and one of the best complicated EOS, namely BKWS- −+×+×+0.1914abcd 59.67 10−−33 16.87 10 0.2224 EOS. Comparison of calculated results with … (2b) experimental data and BKWS-EOS listed in Table 1

may be taken as appropriate validation tests of the Δ−Habd1158.3 − 252.3 + 847.9 Δ=T f introduced simple correlations for use with CNO and −−×+×+0.2964abcd 55.09 10−−33 18.66 10 0.1911 CHNO explosives. It is worthwhile to note that the … (2c) present method is exceedingly simple and at the same time gives results that are comparable predicted to the Δ+Hab625.2 − 142.8 Δ=T f complexities of the other methods involving the 59.05×−×+×+× 10−−−−3333abcd 43.81 10 18.66 10 20.36 10 equation of state of the products. Considering few … (2d) percent deviations generally attributed to experimental measurements and BKW-EOS of where detonation temperatures, the agreement between calculated and measured temperatures is also Δ=TTd −298 … (3) satisfactory.

Table 1⎯Comparison of detonation temperature of the new correlations and BKWS-EOS with measured values

a 13 13 Name Condensed phase ρ0 (g/cc) Texp (K) Td (K) TBKWS-EOS %Dev BKWS- %Dev 13 ΔHf (kJ/mol) (K) EOS new at 298 K

TNT -62.81 1.64 3401 3720 1.45 3401 3780 1.36 3401 3790 1.00 3400 3401 3750 -10.29 -0.03 0.80 3401 3610

ABH 485.69 1.64 4984 4710

TATB -154.29 1.88 3251 3250 1.85 3251 3260

DATB -98.81 1.80 3506 3550 1.78 3506 3690

DIPAM -28.47 1.76 4212 4040

HNAB 284.3 1.60 4621 4620

HNS 78.3 1.60 4136 4150 1.70 4136 4120

NONA 114.72 1.70 4930 4510

TACOT 464.76 1.85 4041 4040 Contd. KESHAVARZ: PREDICTION OF DETONATION TEMPERATURE OF CNO AND CHNO 161

Table 1⎯Comparison of detonation temperature of the new correlations and BKWS-EOS with measured values⎯Contd.

a 13 13 Name Condensed phase ρ0 (g/cc) Texp (K) Td (K) TBKWS-EOS %Dev BKWS- %Dev 13 ΔHf (kJ/mol) (K) EOS new at 298 K

BTF 602.93 1.86 6032 5570 1.76 6032 5600

TNTAB 1130.49 1.74 5847 5640

TETRYL 19.55 1.73 4253 4210 1.71 4253 4220 1.68 4253 4240 1.61 4200 4253 4270 -1.67 -1.27 1.40 4253 4350 1.36 4253 4360 1.20 4300 4253 4380 -1.86 1.08 1.00 4390 4253 4340 1.14 3.11

NM -113.17 1.13 3430 3419 3580 -4.37 0.31

NQ -92.53 1.78 2830 2740 1.72 2830 2760 1.62 2830 2790 1.55 2830 2830

DEGN -416.19 1.38 3689 3690

EXP D -393.58 1.55 3359 3360 1.48 3359 3380

MEN-II -311.09 1.02 2405 2720

LX-14 6.28 1.84 3851 3910

COM A-3 11.89 1.64 3101 3670

COMP B 4.19 1.72 3731 3950

COMP B-3 5.57 1.72 4072 4000

COMP C-3 -27.00 1.60 3554 3790

COMP C-4 13.94 1.66 3288 3760

CYCLOTOL- 78/22 15.53 1.76 3953 4070

CYCLOTOL- 77/23 14.99 1.74 3947 4070

CYCLOTOL- 75/25 13.90 1.76 3933 4050

CYCLOTOL- 70/30 11.14 1.73 3897 4040

CYCLOTOL- 65/35 8.33 1.72 3856 4030

CYCLOTOL- 60/40 5.57 1.74 3812 3990

CYCLOTOL- 50/50 0.04 1.63 3707 4000

OCTOL- 76/23 12.77 1.81 3938 4020

OCTOL- 75/25 12.10 1.81 3929 4010

OCTOL- 60/40 4.15 1.80 3808 3950 Contd. 162 INDIAN J. ENG. MATER. SCI., APRIL 2005

Table 1⎯Comparison of detonation temperature of the new correlations and BKWS-EOS with measured values⎯Contd.

a 13 13 Name Condensed phase ρ0 (g/cc) Texp (K) Td (K) TBKWS-EOS %Dev BKWS- %Dev (K)13 EOS new ΔHf (kJ/mol) at 298 K

PENTOLITE -99.04 1.64 4133 4030

PBX-9007 29.85 1.64 3236 3810

PBX-9011 -16.96 1.77 3545 3720

PBX-9205 24.33 1.67 3463 3870

PBX-9501 9.63 1.84 3930 3970

PA -214.79 1.76 4579 4010 1.71 4579 4030 1.60 4579 4080

LX-01 -115.14 1.24 3965 4230

HMX 75.07 1.89 4297 4070 1.60 4297 4270 1.40 4297 4380 1.20 4297 4450 1.00 4297 4480 0.75 4297 4440

RDX 61.59 1.80 4433 4140 1.77 4433 4160 1.72 4433 4200 1.66 4320 4433 4230 2.08 -2.62 1.60 4433 4280 1.46 4433 4360 1.40 4610 4433 4390 4.77 3.83 1.29 4433 4430 1.20 4610 4433 4460 3.25 3.83 1.10 4433 4480 1.00 4600 4433 4490 2.39 3.63 0.95 4433 4490 0.70 4433 4450 0.56 4433 4450

PETN -538.87 1.76 4401 4280 1.70 4401 4320 1.60 4400 4401 4390 0.23 -0.02 1.45 4401 4490 1.23 4401 4600 0.99 4401 4640 0.88 4401 4640 0.48 4401 4560 0.30 4401 4450 0.25 4401 4400

HNB 41.87 1.97 5510 5470

NG -370.97 1.60 4260 4259 4550 -6.81 0.02

TNM 54.43 1.64 2800 2590 2860 -2.14 7.50

a See Appendix A for glossary of compound names and chemical formulas KESHAVARZ: PREDICTION OF DETONATION TEMPERATURE OF CNO AND CHNO 163

For an explosive formulation, the condensed phase References heat of formation of the mixture can be calculated for 1 Mader C L, Numerical Modeling of Explosives and nd the heat of formation of individual components and Propellants, 2 ed ( CRC Press Florida, USA), 1998. 2 Levine H B & Sharples R E, in Operator’s Manual for knowledge of their percent concentration in the RUBY, Lawrence Livermore Laboratory report UCRL-6815, mixture. The correlations can easily be applied to both Livermore, CA, 1962. pure and mixed explosives without any difficulties. 3 Cowperthwaite M & Zwisler W H, in TIGER Computer Program Documentation, Stanford Research Institute, SRI Results and Discussion publ. no. 2106, 1973. 4 Nichols A L & Ree F H, in CHEQ 2.0 User's Manual, The motivation in this work is to propose a UCRL-MA-106754, Lawrence Livermore National procedure which can be used for determining Laboratory, Livermore, CA, 1990. detonation temperature of explosives of arbitrary 5 Fried L E, Howard W M & Souers P C, in CHEETAH 2.0 density, formed from the elements C, H, N and O. User's Manual, Lawrence Livermore National Laboratory, Livermore, CA, 1998. The explosives in Table 1 cover a wide range in 6 Mader C L, in Detonation properties of condensed explosives oxygen balance and are considered to be computed using the Becker-Kistiakosky-Wilson equation of representative of entire class of CNO and CHNO state, Los Alamos Scientific Laboratory Report LA-2900, explosives. Given the chemical formula of a real or New Mexico, 1963. th hypothetical explosive or mixture of explosives, one 7 Jacobs S J, Proc. 12 Symp Combustion, Pittsburg, PA, Combustion Institute 1969. can estimate reliable detonation temperature that is 8 Cowperthwaite M & Zwisler W H, Proc. 6th Int Symp consistent with large uncertainty of detonation Detonation, Coronads, CA, Washington, DC, 1976. temperature. This method permits a simple calculation 9 Tanaka K, Proc. 8th Int Symp Detonation, Albuquerque, New of detonation temperature of explosives where even Mexico, Washington, DC, 1985. their condensed heat of formation is relatively 10 Ree F H, J Chem Phys, 81 (1984) 1251. 11 Fickett W, in Detonation Properties of Condensed uncertain. As indicated in Table 1, excellent Explosives Calculated with an Equation of State Based on agreement is obtained between measured and Intermolecular Potentials, Los Alamos Scientific Laboratory computed values by BKWS-EOS with calculated Report LA-2712, New Mexico, 1962. values of detonation temperature for all CNO and 12 Fringer M, Lee E, Helm F H, Hayes B, Hornig H, McGuire R, Kahara M & Gudiry M, Proc. 6th Symp Detonation, CHNO explosives. Since the necessary input data for Coronads, CA, Washington, DC, 1976. this method is only heat of formation of explosive that 13 Hobbs M L & Baer M R, Proc. 10th Symp Detonation, can be used for quick calculations of detonation Boston, MA, 1993. temperature with about the same reliance on their 14 Kamlet M J & Jacobs S J, J Chem Phys, 48 (1968) 23. answers as one could attach to the more complex 15 Kamlet M J & Ablard J E, J Chem Phys, 48 (1968) 36. 16 Kamlet M J & Dickinson C, J Chem Phys, 48 (1968) 43. computer code, the results of this work are 17 Keshavarz M H & Oftadeh M, High Temp-High Press, 34 remarkable. An important result is that the values of (2002) 495. condensed heat of formation, which can be 18 Keshavarz M H & Oftadeh M, Bull Korean Chem Soc, 24 determined experimentally or estimated by theoretical (2003) 19. methods33-36, as well as elemental composition of the 19 Keshavarz M H & Oftadeh M, Indian J Eng Mater Sci, 10 (2003) 236. explosive correlate quite well with the measured 20 Keshavarz M H & H. R. Pouretedal, Thermochem Acta, 414 values of detonation temperature. (2003) 203. 21 Kamlet M J & Hurwitz H, J Chem Phys, 48 (1968) 3685. Conclusions 22 Hurwitz H & Kamlet M J, Israel J Technol, 7 (1968) 431. In this study, a relatively accurate method of 23 Rothstein R L & Petersen R, Propellants Explos, 4 (1979) estimating detonation temperature correlations for 56. CNO and CHNO explosives are introduced which is 24 Rothstein R L, Propellants Explos, 6 (1981) 91. 25 Martin M R & Yallop J H, J Trans Faraday Soc, 54 (1958) only based upon the atomic composition of either a 264. pure or mixed explosives and condensed phase heat of 26 Stine J R, J Energ Mater, 8 (1990) 41. formation. 27 Stine J R, Matter Res Soc Symp, 296 (1993) 3. 28 Dobratz B M & Crawford P C, LLNL Explosives Handbook, Acknowledgements Properties of Chemical Explosives and Explosives Simulants, Lawrence Livermore National Laboratory, University of I would like to thank the research committee of California, 1985. Malek-ashtar University of Technology (MUT) for 29 Keshavarz M H & Oftadeh M, in Theory and Practice of supporting this work. Energetic Materials, vol. 5, Pt B, 2003, 271. 164 INDIAN J. ENG. MATER. SCI., APRIL 2005

30 Keshavarz M H, Asian J Chem, (in press). 20 TETRYL: N-Methyl-N-nitro-2,4,6-trinitroaniline th 31 Davis W C & Venable D, Proc. 5 Symp Detonation, ACR- (C7H5N5O8) 184, 1970. 21 TNM: Tetranitromethane (C1N4O8) th 32 Kato Y, Mori N, Sakai H, Sakurai T & Hikita T, Proc. 9 22 TNT: 2,4,6-Trinitrotoluene (C7H5N3O6) Symp Detonation, OCNR 113291-7, 1989. 23 TNTAB: 1,3,5-Triazido-2,4,6-trinitrobenzene (C6N12O6) 33 Rice B M & Hare J, Thermochem Acta, 384 (2002) 377. 24 COMP A-3: 91/9 RDX/WAX (C1.87H3.74N2.46O2.46) 34 Politzer P, Murray J S, Grice M E, Desalvo M & Miler E, 25 COMP B: 63/36/1 RDX/TNT/WAX (C H N O ) Mol Phys, 91 (1997) 923. 2.03 2.64 2.18 2.67 26 COMP B-3: 60/40 RDX/TNT (C H N O ) 35 Rice B M, Pai V V & Hare J, Combust Flame, 118 (1999) 2.04 2.50 2.15 2.68 445. 27 COMP C-3: 70/4/10/5/1/3 RDX/TNT/DNT/MNT/ 36 Keshavarz M H & Oftadeh M, High Temp – High Press, (in NC/TETRYL (C1.90H2.83N2.34O2.60) press). 28 COMP C-4: 91/5.3/2.1/1.6 RDX/Di(2-ethylhexyl)sebacate/ Polyisobutylene/Motor oil (C1.82H3.54N2.46O2.51) Appendix A. Glossary of compound names 29 Cyclotol-78/22: 78/22 RDX/TNT (C1.73H2.59N2.40O2.69) 1 ABH: Azobis(2,2',4,4',6,6'-hexanitrobisphenyl) 30 Cyclotol-77/23: 77/23 RDX/TNT (C1.75H2.59N2.38O2.69) 31 Cyclotol-75/25: 75/25 RDX/TNT (C H N O ) (C24H6N14O24) 1.78 2.58 2.36 2.69 32 Cyclotol-70/30: 70/30 RDX/TNT (C H N O ) 2 BTF: Benzotris(1,2,5-oxadiazole-1-oxide) (C6N6O6) 1.87 2.56 2.29 2.68 33 Cyclotol-65/35: 65/35 RDX/TNT (C H N O ) 3 DATB: 1,3-Diamino-2,4,6-trinitrobenzene (C6H5N5O6) 1.96 2.53 2.22 2.68 34 Cyclotol-60/40: 60/40 RDX/TNT (C H N O ) 4 DEGN: Diethyleneglycol dinitrate (C4H8N2O7) 2.04 2.50 2.15 2.68 5 DIPAM: Dipiramide (C12H6N8O12) 35 Cyclotol-50/50: 50/50 RDX/TNT (C2.22H2.45N2.01O2.67) 6 EXP D: Ammonium picrate (C6H6N4O7) 36 LX-01: 51.7/33.2/15.1 NM/TNM/1-Nitropropane 7 HMX: Cyclotetramethylenetetranitramine (C4H8N8O8) (C1.52H3.73N1.69O3.39) 8 HNAB: 2,2',4,4',6,6'-Hexanitroazobenzene (C12H4N8O12) 37 LX-14: 95/5 HMX/Estane (C4.800H9.1365N8.024O8.2811) 9 HNB: Hexanitrobenzene (C6N6O12) 38 MEN-II: 72.2/23.4/4.4 NM/Methanol/Ethylene diamine 10 HNS: 2,2',4,4',6,6'-Hexanitrostilbene (C14H6N6O12) (C2.06H7.06N1.33O3.10) 11 NG: Nitroglycerine (C3H5N3O9) 39 Octol-76/23: 76.3/23.7 HMX/TNT (C1.76H2.58N2.37O2.69) 12 NM: Nitromethane (CH3NO2) 40 Octol-75/25: 75/25 HMX/TNT (C1.78H2.58N2.36O2.69) 13 NONA: 2,2',2",4,4',4",6,6',6"-Nonanitroterphenyl 41 Octol-60/40: 60/40 HMX/TNT (C2.04H2.50N2.15O2.68) (C18H5N9O18) 42 PBX-9007: 90/9.1/0.5/0.4 RDX/Polystyrene/DOP/Rosin 14 NQ: Nitroguanidine (CH4N4O2) (C1.97H3.22N2.43O2.44) 15 PA: (C6H3N3O7) 43 PBX-9011: 90/10 HMX/Estane (C1.73H3.18N2.45O2.61) 16 PETN: Pentaerythritol tetranitrate (C5H8N4O12) 44 PBX-9205: 92/6/2 RDX/Polystyrene/DOP 17 RDX: Cyclomethylene trinitramine (C3H6N6O6) (C1.83H3.14N2.49O2.51) 18 TACOT: Tetranitrodibenzo-1,3a,4,6a-tetraazapentalene 45 PBX-9501: 95/2.5/2.5 HMX/Estane/BDNPA-F (C12H4N8O8) (C1.47H2.86N2.60O2.69) 19 TATB: 1,3,5-Triamino-2,4,6-trinitrobenzene(C6H6N6O6) 46 PENTOLITE: 50/50 TNT/ PETN (C2.33H2.37N1.29O3.22)