Reaction with mercury fulminate

The reaction of mercury fulminate (33 M = Hg/2) with a halogen gave the first furoxan (although misidentified) to be prepared,1 and it was later... 

The first reaction can be used for the determination of the purity of mercury fulminate. Even in the presence of 0.5 percent moisture, pure mercury fulminate does not react with any of the common metals. However, the standard grade of the compound may contain as much as one percent free mercury, formed by exposure to light or elevated temperatures. The free mercury readily forms amalgams with copper, brass, or bronze, so components containing these metals must be protectively coated if used with mercury fulminate. 

Gamer and Hailes [462] postulated a chain branching reaction in the decomposition of mercury fulminate, since the values of n( 10—20) were larger than could be considered consistent with power law equation [eqn. (2)] obedience. If the rate of nucleation is constant (0 = 1 for the generation of a new nuclei at a large number of sites, N0) and there is a constant rate of branching of existing nuclei (ftB), the nucleation law is... 

No peroxide has found practical use as an explosive, a consequence of the weak oxygen-oxygen bond leading to poor thermal and chemical stability and a high sensitivity to impact. Hexamethylenetriperoxidediamine (HMTD) (46) is synthesized from the reaction of hexamine with 30 % hydrogen peroxide in the presence of citric acid. HMTD is a more powerful initiating explosive than mercury fulminate but its poor thermal and chemical stability prevents its use in detonators. 

Fire or explosion hazard may arise from the foUowing ammonia reactions Reaction with halogens produces nitrogen trihahdes which explode on heating its mixture with fluorine bursts into flame reacts with gold, silver, or mercury to form unstable fulminate-type shock-sensitive compounds similarly, shock-sensitive nitrides are formed when ammonia reacts with sulfur or certain metal chlorides, such as mercuric, or silver chloride liquid ammonia reacts violently with alkah metal chlorates and ferricyanides. 

Mercury fulminate is prepared by the reaction of mercury metal with strong nitric acid and ethanol. The preparative method involves pouring a nitric acid solution of mercury(II) nitrate into ethanol. The reaction is not well understood. 

Beside this basic method of manufacturing mercury fulminate, which is widely practised, there are alternate processes. Angelico [11] recognized that mercury fulminate is formed by treating a mercury solution in an excess of nitric acid with a concentrated aqueous solution of malonic acid in the presence of a small amount of sodium nitrate. The reaction results in a considerable rise of temperature, C02 evolution and the precipitation of the fulminate (L. W. Jones [12]). 

Nef [7] showed that the mercuric salt of nitromethane (obtained by the action of HgCl2 on the sodium salt of nitromethane) decomposes when boiled with dilute hydrochloric acid to produce mercury fulminate. In all probability the following reaction takes place ... 

On treatment with phenylhydrazine, mercury fulminate undergoes reduction to free mercury. The phenylhydrazine changes colour from olive, grey (at the moment when mercury is set free) to reddish-brown. Several hours after the addition of alcohol and dilute sulphuric acid, a red-violet colour appears (Langhans [35]). This reaction may be used for the qualitative detection of mercury fulminate. 

Reactions with metals. When mercury fulminate is boiled with water containing metallic suspensions, the majority of metals (e.g. aluminium, zinc, copper), form their fulminates and mercury is precipitated. Reaction can also occur at room temperature, except with nickel. Other metals may be ranged according to increasing reactivity silver, tin, bismuth, cadmium, iron, lead, copper, zinc, brass, aluminium. With aluminium, the reaction takes only a few hours, yielding a large amount of A1203. 

A similar reaction was observed when mercury fulminate was kept in contact with metals in a damp atmosphere. Aluminium gave a white bloom after only four... 

One of the earliest descriptions of the manufacture of mercury fulminate given by Chevalier [59] is as follows 300 g of mercury are dissolved in 3000 g of cold nitric acid (54% HN03, s.g. 1.34) and the solution is poured into a flask containing 1900 g of 90% alcohol. After few minutes a vigorous reaction begins and crystals are precipitated. On completion of the reaction 238 g and 158 g of alcohol are added in turn. The fulminate is filtered off through a cloth filter and carefully washed free of acid with water. The yield is 118-128 parts of fulminate per 100 parts of mercury, i.e. 83-90% of theoretical. 

Fig. 38. General view of plant for manufacturing mercury fulminate in Atlas Powder Company, according to Davis [62]. On the left, conical flasks with mercury nitrate in nitric acid. On the right, reaction flasks.

Mercury fulminate prepared by one of the methods outlined above is tested to check the acid content and the content of other mercury compounds. When tested with litmus paper, the moist product should give a neutral reaction. A 5 g test sample mixed with 2 g of sodium hydrogen carbonate should not give a black or bluish tint. 

This reaction, together with its products, has been studied by a number of chemists, including Liebig, who gave an account of the elementary chemical composition of fulminate in 1823. The mechanism of the reaction which results in the formation of mercury fulminate was reported by Wieland and by Solonina in 1909 and 1910, respectively. 

Mercury fulminate is prepared by dissolving mercury in nitric acid and then pouring into ethanol. A vigorous reaction takes pace which is accompanied by the evolution of white fumes, then by brownish-red fumes and finally again by white fumes. At the same time crystals of mercury fulminate are formed. The crystals are recovered and washed with water until all of the acid is removed. 

Fulminic acid. HONC, and the fulminates are violently explosive. Utilizing this properly, mercuric fulminate. Hg(ONC) - HiO. is used as a detonator for other explosives. Mercury fulminate is made by the reaction of ethyl alcohol and mercuric nitrate in excess of nitric acid, from which insoluble mere-uric fulminate separates. Silvei fulminate. Agl ONC). is more explosive than mercuric fulminate, and is used in the manufacture of firecrackers Free fulminic acid may be obtained by reaction of potassium fulminate and excess of ether. It volatilizes with the ether upon distilling, and changes rapidly to meiufulminic acid. Related to fulminic acid is fulminuric acid, (HONCn. or NOy-CH(CN)-CONH-. 

The commercial preparation of mercury fulminate is carried out by a process which is essentially the same as that which Howmrd originally recommended. Five hundred or 600 grams of mercury is used for each batch, the operation is practically on the laboratory scale, and several batches are run at the same time. Since the reaction produces considerable frothing, capacious glass balloons are used. The fumes, which are poisonous and inflammable, are passed through condensers, and the condensate, which contains alcohol, acetaldehyde, ethyl nitrate, and ethyl nitrite, is utilized by mixing it with the alcohol for the next batch. 

Figure 93. Fulminate Manufacture. (Courtesy Atlas Powder Company.) At left, flasks in which mercury is dissolved in nitric acid. At right, balloons in which the reaction with alcohol occurs.

Mercury fulminate dissolves readily in an aqueous solution of potassium cyanide to form a complex compound from which it is reprecipitated by the addition of strong acid. It dissolves in pyridine and precipitates again if the solution is poured into water. A sodium thiosulfate solution dissolves mercury fulminate with the formation of mercury tetrathionate and other inert compounds, and this reagent is used both for the destruction of fulminate and for its analysis.10 The first reaction appears to be as follows. 

Acetylene. Contact with acetylene gives explosive mercury(II) acetylide.5 Ethanol. In ethanol, mercury(II) fulminate may be formed.5 Petroleum Hydrocarbons. Risk of violent reaction with petroleum hydrocarbons.6 Phosphine. Aqueous solution reacts with phosphine to give explosive complex.5... 

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