Picrate compositions

Examples of high explosives dusts which may be removed by a vacuum system are TNT, tetryl, ammonium picrate, composition B, and pentolite. A wet collector, which moistens the dust close to the point of origin and keeps it wet until the dust is removed for disposal, is preferred except for ammonium picrate which should be collected in a dry system. 

Picrates, Picric acid combines with amines to yield molecular compounds (picrates), which usually possess characteristic melting points. Most picrates have the composition 1 mol amine 1 mol picric acid. The picrates of the amines, particularly of the more basic ones, are generally more stable than the molecular complexes formed between picric acid and the hydrocarbons (compare Section IV,9,1). 

Dissolve naphthalene in a little spirit, and add an equal quantity of a solution of picric acid in spirit. On cooling, yellow needles of naphthalene picrate separate, C,oHg.CQH20H(NO,)3. Benzene forms colourless crystals, anthracene, scarlet needles, having a similar composition. Sec Appendix, p. 295. 

The first dip given to a fusehead is known as the flashing composition and is of particular importance. Originally copper acetylide was used for this purpose, but it has been superseded by more stable materials. Three common compositions are based on lead picrate, lead mononitroresorcinate and a mixture of charcoal and potassium chlorate respectively. These materials are suspended in a solution of nitrocellulose in amyl acetate and amyl alcohol, known as Zapon. One or more dips, with intermediate drying, give a layer of suitable thickness. 

It has been shown that picrate ion is formed during the hydrolysis of tetrytol. As shown in Table 2-5, picrate was observed in the midrun analyses for all the hydrolysis runs of tetrytol and in the midrun analyses for the mixed M28/Composition B-4 run. For two of the three tetrytol runs, there was a low level of picrate... 

The results from the work done at LANL (see below) failed to find any picrate in the hydrolysates from either Composition B-4 or tetrytol. However, because the detection limit for the method used was not reported, it is not possible to determine whether or not the LANL results are consistent with those reported in the Holston study (Bonnett and Elmasri, 2001). 

The two studies, taken together, suggest that tetryl, not TNT, leads to the formation of picrate, since neither the LANL results nor the Holston results showed the formation of picrate in the absence of tetryl. If this is correct, the formation of lead picrate cannot occur when Composition B and M28 propellant are coprocessed, provided no tetryl contamination is present. The solubility of lead picrate in the reaction medium under consideration is not known. Because lead in solution at high pH is predominantly in the form of plumbite ion (HPb02), the concentration of free Pb2+ ions should be very low, and the solubility product of lead picrate would have to be exceedingly small for... 

All whistle compositions are hazardous to handle, but those containing picrates and gallates are also shock-sensitive with a tendency to explode. Picric acid (2,4,6-trinitrophenol) is, in fact, classed as a high explosive. 

Copp Ubbelohde (Ref 1) reported such studies for Amatols, Eyring et al (Ref 4) for Ammonium Picrate, Tranter (Ref 3) and Davis et al (Ref 8) for TNT castings, Jones Mitchell (Ref 2) for granular TNT pressed Tetryl, Malin et al (Ref 9) for Comp B, and Cook (Ref 7) for some composite expls... 

During World War II the Germans employed, on a small scale, cap compositions containing lead picrate for the manufacture of electric fuses giving few gaseous products. 

During World War II, an improved process was developed for producing petroleum naphthas ensuring unlimited quantities of toluene. Purification techniques were improved for TNT. Composites mixtures of TNT-PETN, TNT-RDX, TNT-tetryl, TNT-ammonium picrate, TNT aluminium, etc., were prepared. 

Bo Molded Composite Propellants are mixts of finely divided, crystalline, self-combustible solids such as ammonium picrate sodium nitrate, held together by a resinous binder and formed into grains by compression mold-... 

Armament Engrg (Ref lb) gives compn props of molded composite proplnt, desig-nated as 49Z Amm picrate 41, K nitrate 50 resin binder 9% d 0.065 lb/in3, Igp 165secs, burning rate lin/sec, temperature sensitivity 0.17%/°F and smoke - heavy... 

C.A.Thomas, USP 2742672 (1956) CA 50, 11018-20 (1956) (Comp proplnt prepd by coating each grain of finely divided Amm picrate-Na nitrate with liq thermosetting resin, pressure molding curing) 5)G.S.Sutherland "The Mechanism of Combustion of an Ammonium Perchlorate Polyester Resin Composite Propellant , Princeton Univ, New Jersey (1956), 233 6)A.J.Zaehringer, "Solid Propellant... 

Ammonium picrate is used in the so-called indoor fireworks which burn with but little smoke and without the production of objectionable odor. On page 71 some of the compositions recommended by Tessier24 for Bengal lights are tabulated. 

Alexander s Explosive Compositions consisted of naphthalene(with one or more other solid hydrocarbons), K picrate and oxidizers such as KNO, or KC10a in various proportion s... 

---