Barium styphnate

The scientific literature is a bit puzzling regarding the history of this substance. Griess is sometimes mentioned as the first chemist who prepared barium styphnate [63] in 1874. It is, however, not true as the article clearly references work of Stenhouse [28] who prepared the barium, lead, and silver salts of styphnic acid for comparison with orcin (5-methylbenzene-l,3-diol) salts of the same metals four years earlier. In addition, the article of Griess is surprisingly often erroneously referred to as the first work publishing preparation of lead styphnate. 

Height at which 100 % initiation occurs (without pressing) measured on pendulum for investigation of sensitivity to flame. 

Barium styphnate (barium salt of 2,4,6-trinitrobenzene-l,3-diol BaS) forms an anhydride and two hydrates, monohydrate and trihydrate only the anhydride and the monohydrate are used in practical applications [20,75,76]. According to Bagal the monohydrate of barium styphnate exists in three polymorphic forms listed in Table 5.9 [33]. 

The red form is not stable and easily changes to the yellow labile form in (a) acidic environments, (b) large amount of residues of solvent or inorganic compounds from precipitation in crystals, or (c) in presence of DNR in TNR. In solution, the red form also changes into the yellow labile form. The red form is slightly soluble in cold water, better in boiling water, and insoluble in ethanol, ether, and other organic solvents. The yellow stable form is less soluble in water than red BaS (about 2.5 times less) [33]. 

Barium styphnate trihydrate forms yellow-orange needles. It is more soluble in water than the monohydrate. Trihydrate loses two crystal waters at 105 °C and red needles of monohydrate are formed [33]. The original work of Griess reports the trihydrate formed as rhombohedric prisms with low solubility in water [63]. 

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Azidoethyl Barium carbonate Barium chlorate Barium nitrate Barium oxalate Barium styphnate BBC... 

Anon, Atlas/Aerospace No 8, 1969, Atlas Chemical Ind, Valley Forge, Pa 19481 reviewed by G. Cohn, Edit in Expls Pyrots 3(3), 1970 under the title Explosives for Actuators [LMNR (Lead Mononitroresorcinate), KDNBF (Potassium Dinitrobenzofuroxane) and BaSt (Barium Styphnate) are the three common materials used as either ignition drops or base charges in actuators, motors, switches, and matches. LMNR, a stable, low-cost compd, is always used with 5 to 40% KCIO3. KDNBF, a higher cost material, is 5 to 10 times more powerful than LMNR. 

A plot of logio Ed against 1/1) is almost rectilinear. Therefore, Ea may be determined by equating (EJ4.57) with the slope of the straight line. Equation 3.3 holds good for a number of explosives such as lead azide, cuprous azide, mercury fulminate, lead styphnate, barium styphnate and metal picrates and metal picramates etc. [25-30]. Thus, it appears that the determination of Ea gives a more complete picture concerning the heat sensitivity of explosives than ED or ET. 

Tompkins and Young [50] examined the thermal decomposition of barium styphnate and found it to be similar to that of lead styphnate hydrate (Fig. 54). 

Primary explosives have a high degree of sensitivity to initiation through shock, friction, electric spark or high temperatures and explode whether they are confined or unconfined. Typical primary explosives which are widely used are lead azide, lead styphnate (trinitroresorci-nate), lead mononitroresorcinate (LMNR), potassium dinitrobenzo-furozan (KDNBF) and barium styphnate. Other primary explosive materials which are not frequently used today are mercury azide and mercury fulminate. 

Ubbelohde et al (Ref) describe a method of detg this period for initiating expls, such as LA (Lead Azide), MF (Mercuric Fulminate), LSt (Lead Styphnate), BaSt (Barium Styphnate) and Basic LDNR (Lead Dinitroresorcinate)... 

The following results are listed Barium Styphnate 12, LMNR (Lead Mononitroresor-cinate)16 and KDNBF (Potassium Dinitro-benzofuroxan) 14... 

Barium Styphnate forms yellow, uniform crystals. The crystals are stable, but may detonate if strongly heated and they deflagrate on ignition. Barium styphnate is well suitable for use in priming compositions for bullets and the like, in pyrotechnic compositions, and rocket propellants. Barium styphnate however, is primarily used as a substitute for lead styphnate in initiation compositions. Barium styphnate should be stored submerged in kerosene. ... 

Summary Barium styphnate is easily prepared by reacting styphnic acid with ammonia solution forming ammonium styphnate. This ammonium styphnate is then converted into the water insoluble barium styphnate by addition of barium chloride dihydrate. The product is then filtered-off, washed, and then dried. Commercial Industrial note For related, or similar information, see Serial No. 360,756, July 28th, 1970, by Atlas Chemical Industries, to Harold F. Bluhm, Tamaqua PA. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult any protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

Barium styphnate can be prepared either as a monohydrate or a trihydrate and the kinetics of tiie dehydrations and the decompositions of both forms have been studied by Tompkins and Young [139]. The decomposition of the dehydrated monohydrate (542 to 581 K) exhibited a sigmoid curve which initially fitted the power law and the induction period was very short E = 153 kJ mol ). Reaction at a non-coherent interface proceeded along grain boundaries and into the sub-grains. 

Tompkins and Young [139] concluded that the reaction of lead styphnate monohydrate (468 to 502 K) was comparable with that of barium styphnate monohydrate. The or-time curves for both salts were not identical, but again there was nucleation at grain boundaries, followed by the advance of a non-coherent reaction interface into the reactant crystallites. The activation energy (138 kJ mol" ) is slightly less than that for the barium salt, but was ascribed to the same primary process, activation of a surface styphnate ion. 

The emery-paper friction test is more discriminating (Tables XI and XII), the test revealing that dextrinated lead azide is less sensitive than Service, RD1333, and RD1343 lead azides. The values obtained for lead styphnate and barium styphnate suggest that they are as friction sensitive as dextrinated lead azide. 

B. Inhalation of insoluble inorganic barium salts can cause baritosis, a benign pneumoconiosis. One death resulted from barium peroxide inhalation. Detonation of barium styphnate caused severe poisoning from inhalation and dermal absorption. 

LS is often used in bridge-wire compositions where it is in direct contact with wire heated by an electric current. An interesting study of the effect of loading density on the hot wire initiation of lead and barium styphnates was carried out by Naval Ordnance Laboratory [42]. It was found that the energy required for the initiation remained constant and the time to ignition decreased as the loading density increased. 

Table 5.9 Differing forms of barium styphnate monohydrate [33]...

Barium styphnate is not very sensitive to impact less than LA and LS. The F of I of this compound is only 40 (while 20 for LS and 15 for LA) [2]. Thermal sensitivity and sensitivity to flame depends on the form. The values for the anhydride and the... 

Direct precipitation of BaS anhydride is not possible as one of three polymorphic forms of the monohydrate is produced depending on reaction conditions. The red form is created when freshly prepared styphnic acid is used for precipitation of barium styphnate. It is formed by direct reaction of equivalent amounts of TNR and barium carbonate. The yellow stable salt is formed when old TNR is used for BaS preparation, in an acidic environment or in excess precipitating agent. It is commonly prepared via the sodium salt of styphnic acid. The trihydrate of BaS forms in reaction mixture with low concentration of reagents and without stirring. The trihydrate also sometimes contaminates the monohydrate [33]. 

Preparation of barium styphnate monohydrate for practical applications is similar to preparation of LS. Magnesium styphnate is used as a starting material which reacts with barium nitrate, chloride, or acetate resulting in precipitation of barium styphnate. A reaction temperature of 60-85 °C is recommended. Product precipitates in form of the trihydrate, which dehydrates to the monohydrate by the slow addition of sufficiently dilute lutric acid [75]. It is difficult to re-crystallize in a suitable form and it is therefore recommended to use a crystal-modifying agent (e.g., carboxymethyl cellulose) [2, 26, 27]. 

Barium styphnate has been used for firearms in Britain since World War II [2]. The type of production process and shape of prepared crystals determines the application of this primary explosive. It is used in delay composition, as an ingredient of primary compositions, as a component of compositions for electric primers or igniters, delay compositions, and so on [2, 3, 75, 76]. 

Leopold, H.S. Effect of loading density on the hot wire initiation of normal lead styphnate and barium styphnate. Report NOLTR-70-96, AD716024, U.S. Naval Ordnance Laboratory, White Oak, Silver Spring (1970)... 

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