Tenney L., Davis Ph.D. - The Chemistry of Powder and Explosives(ru)

nitroguanidine, and guanidine picrate. A mixture of PETN with guanidine picrate is less sensitive to heat and to shock than ordinary colloided smokeless powder, and is stable at all temperatures which are likely to be encountered. PETN does not colloid with nitrocellulose. It dissolves readily in warm trinitrotoluene, and mixtures may be prepared which contain 65% or more of PETN. The richer mixtures may be used as propellent powders. The less-rich mixtures are brisant and powerful high explosives comparable in their behavior and effects to TNB.

Stettbacher 113 in 1931 described several dynamite-like explosives which contained both PETN and nitroglycerin. He called them by the general name of Penthrinit, and described simple penthrinit, gelatin penthrinit, and ammonpenthrinit. Naoum 114 later in the same year reported comparative tests of ammonpenthrinit and gelatin dynamite, as follows.

A Swiss patent of 1932 to Stettbacher11B covers the conversion of PETN into a plastic mass by means of 10-30% of a fluid nitric ester such as nitroglycerin or nitroglycol. It states that a mixture of 80% PETN and 20% nitroglycerin is a plastic mass, density 1.65, which does not separate into its components and which is suitable for loading shells and detonators. For the latter purpose it is initiated with 0.04 gram of lead azide.

Dipentaerythrite Hexanitrate (Dipenta)

The formation of a certain amount of dipentaerythrite is unavoidable during the preparation of pentaerythrite. It is nitrated

113 Z. ges. Schiess- u. Sprengstoffw., 26, 8, 39 (1931). "4/forf., 26, 42 (1931).

"B Swiss Pat. 137,476 (1932).

along with the latter substance, and, unless a special purification is made, remains in the PETN where its presence is undesirable because of its lower stability.

HO - CH2-C - CH2-(OH"™l|iO - CH2- C -CH2- OH

N02-O-CH2-C-CH2-0-CH2-C-CH2-ONO2

Dipentaerythrlte hexanltrate

Dipentaerythrite hexanitrate116 is procured in the pure state by the fractional crystallization from moist acetone of the crude PETN which precipitates when the nitration mixture is drowned

temperature than PETN, but it is less stable and decomposes much more rapidly at 100°.

Briin 117 reports measurements by the Dautriche method of the

NITROPENTANONE AND RELATED SUBSTANCES 285

nitromethane trinitrate gives a poorer potassium iodide 65.5° heat test than nitroglycerin. Naoum 12° reports the data which are tabulated below.

Nitropentanone and Related Substances

Cyclopentanone and cyclohexanone contain four active hydrogen atoms and condense with formaldehyde to form substances which contain four —CH2—OH groups. The latter may be converted directly into explosive tetranitrates or they may be reduced, the carbonyl groups yielding secondary alcohol groups,

The explosives derived in this way from cyclopentanone and cyclohexanone were patented in 1929 by Friederich and Flick.121 They

120 Op. dt., p. 241.

121 Ger. Pat. 509,118 (1929).

CHAPTER VI

SMOKELESS POWDER

An account of smokeless powder is, in its main outlines, an account of the various means which have been used to regulate the temperature and the rate of the burning of nitrocellulose. After the degree of nitration of the nitrocellulose, other factors which influence the character of the powder are the state of aggregation of the nitrocellulose, whether colloided or in shreds, the size and shape of the powder grains, and the nature of the materials other than nitrocellulose which enter into its composition.

Bulk Powder

The first successful smokeless powder appears to have been made by Captain Schultze of the Prussian Artillery in 1864. At first he seems only to have impregnated little grains of wood with potassium nitrate, but afterwards he purified the wood by washing, boiling, and bleaching, then nitrated it, purified the nitrated product by a method similar to that which had been used by von Lenk, and finally impregnated the grains with potassium nitrate alone or with a mixture of that salt and barium nitrate.1 The physical structure of the wood and the fact that it contained material which was not cellulose both tended to make the nitrated product burn more slowly than guncotton. The added nitrates further reduced the rate of burning, but Schultze's powder was still too rapid for use in rifles. It found immediate favor for use in shot guns. It was manufactured in Austria by a firm which in 1870 and 1871 took out patents covering the partial gelatinization of the powder by treatment with a mixture of ether and alcohol. The improved powder was manufactured between 1872 and 1875 under the name of Collodin, but the Austrian gov-

ifirit. Pat. 900 (1864).

287

ernment stopped its manufacture on the grounds that it infringed the government's gunpowder monopoly. A company was formed in England in 1868 to exploit Schultze's invention, a factory was established at Eyeworth in the New Forest in 1869, and the

FIGUBB 70. Shreddy Grains of Bulk Powder (25X)- (Courtesy Western

Cartridge Company.)

methods of manufacture were later improved by Griffiths and achieved great success. In 1883 Schultze enterad into a partnership in Germany and started a factory at Hetzbach in HesseDarmstadt.

The next successful smokeless powder was invented 2 at the works of the Explosives Company at Stowmarket in England. It

2 Brit. Pat. 619 (1882) to Walter F. Reid and D. Johnson.

was called E. C. powder (Explosives Company), and consisted of nitrocotton mixed with potassium and barium nitrates with the addition of coloring matter and small amounts of other organic material. It was made into grains which were hardened by being partially gelatinized with ether-alcohol. A separate company was organized to develop the invention, and the manufacture was started at Green Street Green, near Dartford, in Kent.

Schultze powder and E. C. powder are known as bulk sporting powders, either because they are loaded by bulk or because, for the same bulk, they have about the same power as black powder. Bulk powders burn quickly. They are used in shot guns, in hand grenades, in blank cartridges, and occasionally in the igniter charges which set fire to the dense colloided propellent powder which is used in artillery.

Bulk powders are made in considerable variety, but they consist always of nitrocellulose fibers which are stuck together but are not completely colloided. Some contain little else but nitrocellulose; others contain, in addition to potassium and barium nitrates, camphor, vaseline, paraffin, lampblack, starch, dextrine, potassium dichromate or other oxidizing or deterrent salts, and diphenylamine for stabilization, and are colored in a variety of brilliant hues by means of coal-tar dyes. In the United States bulk powders are manufactured by one or the other of two processes, either one of which, however, may be modified considerably; the materials are incorporated under wooden wheels, grained, and partially gelatinized, or the grains are formed in a still where a water suspension of pulped nitrocellulose is stirred and heated with a second liquid, a solvent for nitrocellulose which is volatile and immiscible with water.

Three typical bulk powders are made up according to the

the nitrocellulose is an average secured by mixing pyrocellulose and guncotton. A batch usually amounts to 200 pounds, 100