Picrate powder

In World War II a variety of picrate powder consisting of ammonium picrate, potassium or sodium nitrate and a binding agent was introduced in Great Britain and in the U.S.A. as the propellant charge for small rockets. This was reported more fully in a chapter devoted to mixtures for rocket propulsion (p. 365). 

The progress made in recent years in the manufacture of smokeless powders has been very great. With a few exceptions, nearly all these powders are nitro compounds, and chiefly consist of some form of nitro-cellulose, either in the form of nitro-cotton or nitro-lignine or else contain, in addition to the above, nitro-glycerine, with very often some such substance as camphor, which is used to reduce the sensitiveness of the explosive. Other nitro bodies that are used, or have been proposed, are nitro-starch, nitro-jute, nitrated paper, nitro-benzene, di-nitro-benzene, mixed with a large number of other chemical substances, such as nitrates, chlorates, c. And lastly, there are the picrate powders, consisting of picric acid, either alone or mixed with other substances. 

Place a mixture of 0-5 g. of finely powdered thiourea, 0-5 g. of the alkyl halide and 5 ml. of alcohol in a test-tube or small flask equipped with a reflux condenser. Reflux the mixture for a j)eriod depending upon the nature of the halide primary alkyl bromides and iodides, 10-20 minutes (according to the molecular weight) secondary alkyl bromides or iodides, 2-3 hours alkyl chlorides, 3-5 hours polymethy lene dibromides or di-iodides, 20-50 minutes. Then add 0 5 g. of picric acid, boil until a clear solution is obtained, and cool. If no precipitate is obtained, add a few drops of water. RecrystaUise the resulting S-alkyl-iso-thiuronium picrate from alcohol. 

Vaseline, Castor oil, Olivo oil, Sal volatile, Boracic acid powder, Sodium bicarbonate powder, Chloramiue-T powder. Sulpha-pyridine powder, Butesin picrate ointment. 

Chondrodine, CigHji04N, amorphous, m.p. 218-20°, [a]n — 75 (EtOH). The hydrochloride, B. HCl, m.p. 274-5°, occurs in yellow leaflets the picrate, m.p. 193-4°, is a crystalline powder, and the picrolonate m.p. 185-6°, forms greenish-yellow needles. The alkaloid contains e methoxyl and a methylimino-group, and yields a crystalline dibenzoy derivative, m.p. 295°. The diethyl ether hydrochloride, m.p. 258°, forms yellow needles (Scholtz, 1911). 

Lettocine, Cj7H2502N, is a pale brown microcrystalline powder, m.p. 350-2° it yields a crystalline hydriodide, B. HI, m.p. 256° dec.) picrate, m.p. 198°, and is recovered unchanged from boiling acetic anhydride. Bertho suggested that it may be a condensed form of a Kurchi alkaloid (p. 742). 

Cerium Picrate. [C6H2(N02)30]3Ce, mw 824.45, N 15.29%, brown powder which explds violently at 306—13°. Can be prepd by heating either its trlhydrate or undecahydrate Refs 1) Beil 6,277 2) O. Silberrad H.A. 

Ferrous Picrate. [C6H2(N02)30] 2Fe, mw 513.15, N 16.38%, dark green powder which expld feebly at 315—20°. It was obtained by drying the octahydrate in a vac dessicator over sulfuric acid. Its impact sensitivity was 14-15" (vs 14" for TNT). The octahydrate was obtained by treating a hot coned aq soln of ferrous sulfate with Ba picrate yel hexagonal prisms which turned brown on standing impact sensitivity 36"... 

Note Sodium Picrate, Double Salts of. When an aq soln of Na picrate (3 moles) is stirred and heated with 3 moles of finely powdered Ba or Fb picrate, the resulting double salts are less sensitive to impact than the single salts (and for this reason are less dangerous to handle). The same can be said for other picrate double salts (Ref 4)... 

Tropinone. 10 g of pyrrolidinediethyl diacetate are heated with 10 g of cymene and 2 g of sodium powder, the reaction taking place at about 160°. During the reaction (which is complete in about 10 min) the temp should not exceed 172°. The resulting reaction product is dissolved in water, then saturated with potassium carbonate, and the oil, which separates, is boiled with dilute sulfuric acid. 2.9 g of tropinone picrate forms and is filtered. 

Halsey and Savage Explosives. Several smokeless powders, containing Ammonium Picrate, were patented in the US in 1896. They were prepd by adding finely pulverized Ammonium Picrate to an aqueous solution of potassium dichromate in such a manner as to form a plastic mass and then slowly adding a coned aqueous solution of potassium permanganate. 

K2Cr207 25, KMn04 7%. No 2 Sporting Powder Amm Picrate 73, K2Cr207 20, KMn04 7%. No 3 Rifle Powder Amm Picrate 50,... 

Hill Powder. Has been used for loading shells NH4 Picrate 43.0, K Picrate 53.5 charcoal 3.5... 

Jahnite Powders. Austrian mining expls patented by Jahn many years ago. They contained NaN03 70—75, sulfur 12—10, lignite 17—10, KC103 0.4-2, Na Picrate 0-3, PA 0.3-0 NaC03 0.3-0%... 

Jalnias Powders. The following compns for Cannon Powder - KN03 75, Na Picrate 3, sulfur 10, coal 10 KC103 2% and Rifle Powder — KN03 15, Na Picrate 8, sulfur 10, coal 15 KC103 2% are found in Ref Ref Perez Ara (1945), p 223... 

Chap XIII (Amatol) Chap XIV, Pt 1 (Picric Acid) Chap XIV, Pt 2 (Ammonium Picrate) Chap XV (Nitrostarch Explosives) Chap XVI, Pt 1 Pt 2 (Tetryl) Chap XVII (Black Powder) Chap XVIII (Primers and detonators)... 

Ammonium picrate [also known as Explosive D Structure (2.9)] was used as a military explosive to fill armor-piercing shells because of its relative insensitiveness to impact It was also used in admixture with KN03 as a substitute for black powder or gunpowder. Ammonium picrate in conjunction with TNT [Picratol-52/48 (Ammonium picrate/TNT)] was also formulated and used. 

Various loose powder mixtures of ammonium picrate and aluminium were also used by the Japanese during World War II. They will be dealt below, as mixtures with aluminium. 

Blackpowder and small arms powder contained 9-16% and ca. 23% potassium picrate, respectively. 

The new propellant was promising but the nitrocellulose smokeless powder invented soon afterwards superseded all mixtures containing potassium nitrate and similar salts, that give a number of solid particles when exploded. For a time in the United States various mixtures were still used instead of blackpowder—chiefly for sporting purposes. E.g. Gold Dust Powder (Starke [36]) consisted of 55% ammonium picrate, 25% potassium picrate and 20% ammonium bichromate. Soon, however, early in the nineteenth century, the use of these mixtures was discontinued. 

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