Meyer R., Koehler J., Homburg A. Explosives. Wiley-VCH, 2002 / Explosives 5th ed by Koehler, Meyer, and Homburg (2002)

165	Heat Sensitivity

Heat Sensitivity

thermische Sensibilität; sensitiveness to Heat; sensibilit´ au chauffage

Heat sensitivity is determined by testing the flammability of explosives brought into contact with glowing objects, flame, sparks, the initiating flame of a black powder safety fuse, a red-hot iron rod, or a flame.

RID (Reglement` International concernant le Transport des Marchandises Dangereuses) describes a method, in which a sample of about 500 g of the explosive, accommodated in a metal can of given dimensions, is exposed to a wood fire, and its behavior (combustion, intense decomposition or detonation) is observed.

In response to a suggestion made by Koenen (Bundesanstalt für Materialprüfung, Berlin, Germany), these tests, which are carried out with the purpose of evaluating the safety during transport, were improved as described below; the method is known as the “steel sleeve test” (Koenen test).

Koenen Test Procedure

The sample substance is introduced into a cylindrical steel sleeve (25 mm dia. V 24 mm dia. V 75 mm) up to a height of 60 mm, and the capsule is closed with a nozzle plate with a central hole of a given diameter. The diameter of the hole can vary between 1 and 20 mm; when the plate is not employed, the effect is equivalent to that of a 24-mm hole. The charged sleeve is placed inside a protective box and is simultaneously heated by four burners; the time elapsed up to incipient combustion and the duration of the combustion itself are measured with a stop watch. The plate perforation diameter is varied, and the limiting perforation diameter corresponding to an explosion caused by accumulation of pressure inside the steel sleeve is determined. Explosion is understood to mean fragmentation of the sleeve into three or more fragments or into a greater number of smaller fragments.

Heat Sensitivity	166

In this way, reproducible numerical data are obtained which allow classification of different explosives according to the explosion danger they represent.

The parameter which is reported is the largest diameter of the circular perforation in mm (limiting diameter) at which at least one explosion occurs in the course of three successive trials.

Fig. 15. Steel sleeve test (Koenen test)

167			Heptryl
Table 18. Results of steel sleeve test
Explosive Material	Limiting	Time	Time of
	Diameter	until	Combustion
		Ignition
	mm	s	s
A. Homogeneous Explosives
nitroglycerine	24	13	0
nitroglycol	24	12	10
nitrocellulose, 13.4 % N	20	3	0
nitrocellulose, 12.0 % N	16	3	0
Cyclonite	8	8	5
ammonium perchlorate	8	21	0
PETN	6	7	0
Tetryl	6	12	4
TNT	5	52	29
picric acid	4	37	16
dinitrotoluene	1	49	21
ammonium nitrate	1	43	29
B. Industrial Explosivesblasting
gelatin	24	8	0
guhr-dynamite	24	13	0
Gelignite	20	7	0
ammonium nitrate gelatin	14	10	0
ammonium-nitrate-based
powder-form explosives	1.5 – 2.5	25	40
nitrocarbonitrates	2	25	4
ANFO blasting agents	1.5	33	5
gelatinous permitted
explosives	14	12	0
ion-exchanged powder-
form permitte
explosives	1	35	5

Heptryl

N-(2,4,6 Trinitrophenyl-N-nitramino)-trimethylolmethane Trinitrate; Trinitrate de trinitroph´enyl-nitramino-trim´ethylolm´ethane

yellow crystals

empirical formula: C10H8N8O17 molecular weight: 512.24

energy of formation: – 96.8 kcal/kg = – 405.0 kJ/kg

Hermetic Seal	168

oxygen balance: – 21.9 % nitrogen content: 21.9 %

volume of explosion gases: 787 l/kg specific energy: 128.6 mt/kg = 1261 kJ/kg melting point (decomp.): 154 °C = 309°F deflagration point: 180 °C = 356°F

heat of combustion: 2265.9 kcal/kg

Heptryl is comparable in power and sensitivity to PETN. It can be prepared by nitrating 2,4-dinitroanilinotrimethylolmethane with mixed nitric-sulfuric acid and purified by reprecipitation from acetone.

Hermetic Seal*)

Hermetische Versiegelung; diaphragme herm´etique

Seal impervious to air and fluids.

HEX

Abbreviation for high energy explosive. The HEX series comprises modifications of W Torpex.

Hexal

Mixture of RDX, aluminum powder and added wax as phlegmatizer. It is used, press-molded, as a filling of anti-aircraft gunshells. Owing to the aluminum component, both an incendiary and explosive effect are obtained.

Hexamethylene Diisocyanate

Hexamethylendiisocyanat; diisocyanate d’hexam´ethyl`ene

O=C=N–(CH2)6–N=C=O

colorless liquid

empirical formula: C8H12N202 molecular weight: 168.2

energy of formation: – 468 kcal/kg = –1961 kJ/kg enthalpy of formation: – 496 kcal/kg = 2078 kJ/kg oxygen balance: – 205.4 %

nitrogen content: 16.66 %

* Text quoted from glossary.

169	Hexamethylenetetramine Dinitrate

density 20/4: 1.0528 g/cm3

boiling point at 0.013 bar: 124 °C = 255°F

The compound acts as a hydroxy curing agent in the formation of polyurethane binders of W Composite Propellants; W also Casting of Propellants.

Hexamethylenetetramine Dinitrate

Hexametylentetramindinitrat; dinitrate d’hexam´ethyl´ene t´etramine

colorless crystals

empirical formula: C6H14N6O6 molecular weight: 266.2

energy of formation: – 309.9 kcal/kg = –1296.6 kJ/kg enthalpy of formation:

– 338.8 kcal/kg = –1417.7 kJ/kg oxygen balance: – 78.3 % nitrogen content: 31.57 %

volume of explosion gases: 1081 l/kg heat of explosion

(H2O liq.): 631 kcal/kg = 2642 kJ/kg (H2O gas): 582 kcal/kg = 2434 kJ/kg specific energy: 76.4 mt/kg = 749 kJ/kg

melting point (decomposition): 158 °C = 316°F lead block test: 220 cm3/10 g

impact sensitivity: 1.5 kpm = 15 Nm

friction sensitivity: at 24 kp = 240 N pistil load reaction

This salt is soluble in water, but is insoluble in alcohol, ether, chloroform, and acetone.

Hexamethylenetetramine dinitrate can be prepared from hexamethylenetetramine and nitric acid of medium concentration; it is an important precursor of RDX (W Cyclonite) manufactured by the Sachmann method.

Hexamethylenetriperoxide Diamine	170

Hexamethylenetriperoxide Diamine

Hexamethylentriperoxiddiamin; hexam´ethyl`enetriperoxyde diamine; HMTD

colorless crystals

empirical formula: C6H12N2O6 molecular weight: 208.1

energy of formation: – 384.3 kcal/kg = –1608 kJ/kg enthalpy of formation:

– 413.7 kcal/kg = –1731 kJ/kg oxygen balance: – 92.2 % nitrogen content: 13.46 %

volume of explosion gases: 1075 l/kg heat of explosion

(H2O liq.): 825 kcal/kg = 3450 kJ/kg (H2O gas): 762 kcal/kg = 3188 kJ/kg specific energy: 87.3 mt/kg = 856 kJ/kg

density: 1.57 g/cm3

lead block test: 330 cm3/10 g

detonation velocity: 4500 m/s = 15 000 ft/s deflagration point: 200 °C = 390 °F beginning of decomposition: 150 °C = 300 °F impact sensitivity: 0.06 kp m = 0.6 N m

friction sensitivity: at 0.01 kp = 0.1 N pistil load reaction

This peroxide is practically insoluble in water and in common organic solvents. It is prepared from hexamethylenetetramine and hydrogen peroxide in the presence of citric acid, with efficient cooling.

It is an effective initiating explosive; nevertheless, it cannot be employed in practice owing to its poor storage properties. The thermal stability is low.

Weight loss (%):

after	60 °C	75 °C	100	°C
	at
hours	140 °F	167 °F	212	°F
2	0.10	0.25	3.25
8	0.35	0.60	29.6
24	0.5	1.3	68.0
48	0.5	2.25; smell	decomp.

171	2,4,6,2',4',6'-Hexanitrobiphenyl

Hexanitroazobenzene

Hexanitroazobenzol; hexanitroazobenz`ene

orange red crystals

empirical formula: C12H4N8O12 molecular weight: 452.2 oxygen balance: – 49.7 % nitrogen content: 24.78 % melting point: 221 °C = 430 °F

This compound can be prepared from dinitrochlorobenzene and hydrazine. The tetranitrohydrazobenzene, which is obtained as an intermediate product, is treated with mixed acid, yielding hexanitroazobenzene by simultaneous oxidation and nitration. It is a more powerful explosive than hexanitrodiphenylamine.

2,4,6,2',4',6'-Hexanitrobiphenyl

Hexanitrobiphenyl; hexanitrobiph´enyle

pale yellow crystals

empirical formula: C12H4N6O12 molecular weight: 424.2 oxygen balance: – 52.8 % nitrogen content: 19.81 % density: 1.6 g/cm3

melting point: 263 °C = 505 °F lead block test: 344 cm3/10 g deflagration point: 320 °C = 610 °F

Hexanitrobiphenyl is insoluble in water, but is soluble in alcohol, benzene, and toluene. It is a rather heat-intensive explosive.

2,4,6,2',4',6'-Hexanitrodiphenylamine	172

2,4,6,2',4',6'-Hexanitrodiphenylamine

dipicrylamine; Hexanitrodiphenylamin; hexanitrodiphenylamine; Hexyl; hexite; HNDPhA: HNDP

yellow crystals

empirical formula: C12H5N7O12 molecular weight: 439.2

energy of formation: +38.7 kcal/kg = +162 kJ/kg enthalpy of formation: +22.5 kcal/kg = +94.3 kJ/kg oxygen balance: – 52.8 %

nitrogen content: 22.33 %

volume of explosion gases: 791 l/kg heat of explosion

(H2O liq.): 974 kcal/kg = 4075 kJ/kg (H2O gas): 957 kcal/kg = 4004 kJ/kg specific energy: 112 mt/kg = 1098 kJ/kg

density: 1.64 g/cm3

melting point: 240 – 241 °C = 464 – 466 °F (decomposition)

lead block test: 325 cm3/10 g detonation velocity, confined:

7200 m/s = 23 600 ft/s at r = 1.60 g/cm3 deflagration point: 250 °C = 480 °F impact sensitivity: 0.75 kp m = 7.5 N m friction sensitivity: up to 36 kp = 353 N

pistil load no reaction

critical diameter of steel sleeve test: 5 mm

This explosive is toxic (the dust attacks the skin and mucous membranes) and light-sensitive. It is insoluble in water and most organic solvents. It forms sensitive acid salts.

It is prepared by nitration of asym-dinitrodiphenylamine with concentrated nitric acid. asym-Dinitrodiphenylamine is formed by condensation of dinitrochlorobenzene with aniline.

Its stability and brisance, as well as its sensitivity, are somewhat higher than those of picric acid.

Hexanitrodiphenylamine has been employed in underwater explosives in the form of pourable mixtures with TNT and aluminum powder. Since hexanitrodiphenylamine is toxic and is strongly colored, such mixtures are replaced by better ones (W Torpex; W HBX).

173	Hexanitrodiphenylglycerol Mononitrate

By itself hexanitrodiphenylamine is an explosive with a relatively low sensitivity to heat.

The compound has been used as a precipitant for potassium.

Specifications

melting point: not less than	230 °C = 446 °F
insolubles in 1 : 3 pyridine
acetone mixture: not more than	0.1 %

Hexanitrodiphenylaminoethyl Nitrate

Hexanitrodiphenylaminoäthylnitrat; nitrate d’hexanitrodiph´enyleamino´ethyle

pale yellow platelets empirical formula: C14H8N8O15 molecular weight: 528.3 oxygen balance: – 51.5 % nitrogen content: 21.21 %

melting point: 184 °C = 363 °F

deflagration point: 390 – 400 °C = 735 – 750 °F

Hexanitrodiphenylglycerol Mononitrate

Heptanitrophenylglycerin; mononitrate d’hexanitrodiph´enyleglyc´erine

yellow crystals

empirical formula: C15H9N7O17 molecular weight: 559.3 oxygen balance: – 50.1 % nitrogen content: 17.22 %

melting point: 160 –175 °C = 320 – 347 °F

2,4,6,2',4',6'-Hexanitrodiphenyl oxide	174

lead block test: 355 cm3/10 g

impact sensitivity: 2.3 kp m = 23 N m

This compound is soluble in glacial acetic acid, sparingly soluble in alcohol, and insoluble in water.

It is prepared by dissolving glyceryl diphenyl ether in nitric acid and pouring the resulting solution into mixed acid.

2,4,6,2',4',6'-Hexanitrodiphenyl oxide

Hexanitrodiphenyloxid; hexanitrodiph´enyloxyde

yellow crystals

empirical formula: C12H4N6O13 molecular weight: 440.2 oxygen balance: – 47.3 % nitrogen content: 19.09 % density: 1.70 g/cm3

melting point: 269 °C = 516 °F lead block test: 373 cm3/10 g detonation velocity, confined:

7180 m/s = 23 600 ft/s at r = 1.65 g/cm3 impact sensitivity: 0.8 kp m = 8 N m

Hexanitrodiphenyl oxide is soluble in water, but is sparingly soluble in alcohol and ether. It is a very stable compound, which is less sensitive to impact, bat is a more powerful explosive than picric acid. It is prepared by nitrating dinitro-, trinitro-, tetranitroand pentanitro-substi- tuted diphenyl ether with mixed acid.

2,4,6,2',4',6'-Hexanitrodiphenylsulfide

Hexanitrodiphenylsulfid; Picrylsulfid; hexanitrodiphenylsulfide

reddish-yellow granular powder empirical formula: C12H4N6O12 molecular weight: 456.2 oxygen balance: – 56.1 %