Other salts of fulminic acid

Among other fulminates, the silver salt, (CNO)2Ag, is of some importance. It is prepared in a way similar to mercury fulminate, by the action of alcohol on a silver solution in nitric acid. Silver fulminate, however, is of little value as an explosive since silver is an expensive raw material. Detonators of silver fulminate were employed only in the Italian Navy. 

The other fulminates are of no practical value. They are prepared from mercury fulminate either by reacting the metal amalgam with a suspension of mercury fulminate in water (this is applicable to the majority of metals, including the alkali metals, or simply by the action of the metal itself (e.g. zinc or thallium) which displaces mercury from mercury fulminate (also in water). For example, chips of thallium, zinc, or copper are allowed to stand for some time in a suspension of mercury fulminate in water, the corresponding metal fulminate is gradually formed. 

Fulminate Initiation temperature °C Sensitiveness to impact, work in kgm/cm2 

Rosenberg [63] investigated the properties of sodium, potassium, calcium, strontium, barium, cadmium, cupric, copper, manganese, thallium and silver fulminates and compared them with mercury fulminate. Some of this results are shown in Table 24. 

Martin [64] examined the initiating properties of certain fulminates, and found that silver, cadmium and copper fulminates have stronger initiating properties than mercury fulminate. Table 25 and Fig. 45 show the figures obtained by Wohler and Martin [65], expressed as the smallest amounts of the fulminate of different metals necessary to produce detonation of various high explosives. 

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Burning under reduced pressure Initiating properties of mercuric fulminate Other salts of fulminic acid Manufacture of mercuric fulminate Esters of fulminic acid I lydra >ic acid, its derivatives and salts Decomposition of azides HctcrtK yclics from azides Other react ions of azide anion amt radical Some organic azides Danger of handling a/ides Cyanic triazide... 

The only other salt of fulminic acid which was in some limited use was silver fulminate. However it no longer seems to be in use, and other salts were also of no use. 

Mercury fulminaic tnanut aciure Storage and further processing of mercury fulminate Treatment of waste Other salts of fulminic acid Literature... 

The other potential isomer of HOCN (in addition to isocyanic acid [H-N=C=0] and cyanic acid [H-O-CfeN]) is fulminic acid (H-0-N sC ), which is also incapable of isolation as the free acid (since attempts to do so result in polymerization). However, salts of fulminic acid are known and mercury fulminate, prepared by treatment of a mixture of mercury and ethanol with nitric add, is used commercially as a detonator (blasting cap) for explosives. 

Fulminic Acid, C=N--OH.—Salts of this acid are obtained when nitric acid, alcohol, and mercury or silver are brought together in certain proportions. Mercuric fulminate, (CNO)2Hg, is prepared for use in percussion caps, which are used to explode gunpowder, dynamite, and other explosives. Free fulminic acid is a very unstable volatile liquid. It resembles closely hydrocyanic acid in odor and poisonous properties. 

Fulminic acid C = NOH is a gaseous, highly toxic substance with an odour resembling that of hydrogen cyanide. It is isomeric with other acids cf the same empirical formula HCNO. The chief of these is cyanic acid HCNO, which is obtainable only in the form of its salts free cyanic acid is unstable. The action of inorganic acids on cyanates leads to the evolution of cyanic acid which hydrolyses to form carbon dioxide and ammonia ... 

Aqueous solutions of organic acids such as formic, acetic, and oxalic, decompose mercury fulminate, forming the corresponding mercuric salts. On the other hand, the action of dilute inorganic acids involves decomposition with formation of C02. 

Fulminic Acid or Paracyanic Acid (Oxime of Carbon Monoxide) (Knallsaure in Ger Acide fulminique in Fr Gremuchaya Kislota in Russ), HONCC mw 43.03, N 32.56%, OB to C02 —55.8%. Known in solution, forms variously expl metallic salts known as fulminates. The mercury salt, apparently the first discovered was formed by the action of mercuric nitrate on ethyl alcohol (Ref 2). The free acid can be isolated in cold ether and below —5° may exist as a gas for a short time. When heated it polymerizes to meta-fulminuric acid, HC.C(=NOH)C(=NOH)O.N. Other methods of... 

Tri-nitro toluene cannot be exploded by a flame nor by heating in the open, and is only slightly decomposed by striking it a blow. It is best exploded by means of a detonator of fulminate of mercury. It is used for military purposes in shells, bombs and submarine mines. It also forms a constituent of many mixed explosives. It is about 5 per cent less powerful and also less violent and less sensitive than picric acid (p. 630), and does not form sensitive salts or other products under storage conditions as does the latter. A few examples may be given of mixed explosives made with tri-nitro toluene in which ammonium nitrate is used as an oxidizer. The presence of the nitrate weakens the power of the T.N.T , but the mixtures are not very sensitive and are adapted to military purposes and some of them to mine blasting. 

Any commercial application of sodium or other alkali-metal fulminates is unknown. They are formed by the reactions of alkali-metal salts with nitric acid and ethanol. Sodium fulminate is highly sensitive to shock and heat. It explodes when warmed or lightly touched with a spatula or a glass rod. It forms a double salt with mercuric fulminate, which is unstable and explodes readily. 

Fulminates other than those of Hg and Ag (and also complex Na[Au(CNO)2] from AuCls [110]) cannot be prepared directly by reaction of the metal with nitric acid and subsequently with ethanol like MF or SF [15, 33]. Several reasons exist that make direct formation of other fulminates impossible. Wohler and Martin reported that solubility of most fulminates in the reaction mixture is a reason why only MF and SF can form directly. Most other fulminates are soluble and unstable in the reaction mixture, in which they decompose [57]. Another reason is that the fulminic acid too readily forms complex salts and therefore simple fulminates cannot be isolated [35]. A catalytic effect of noble metals (Hg, Ag) on some of the reaction steps of fulminate formation was reported by Krauz. He mentioned the analogy of the catalytic effect of mercuric ions on hydrocarbons that are oxidized to the relevant nitrophenols in dilute nitric acid [35]. 

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