Fulminic acid, 132

Fulminic acid is a gaseous, very toxic, and unstable substance with a hydrogen cyanide-like odor but much more aggressive [1,2]. Its melting point is —10 °C with decomposition [3]. The structure of fulminic acid is demonstrated above with the left-hand structure being dominant. 

The stmcture of fulminic acid was originally believed to be linear. Based on the IR spectra and theoretical calculations, it was, however, proved that fulminic acid does not have linear, but rather an unusual quasi-linear molecule with angle between H—C—N of precisely 165.13° [8, 10, 11]. The isomers of fulminic acid have attracted the attention of theoreticians and are even the topic of some recent papers [8,19]. A comprehensive review of fulminic acid and its salts was published relatively recently by Wolfgang Beck [8]. 

The structure of metallic salts of fulminic acid is usually presented by a Pauling-like structure with metal bonded to carbon [3, 20-22], This seems to be a reasonable assumption even though some authors published studies supporting bonding between metal and oxygen [23] or even the possibility of the existence of both of these forms [24], The issue still causes discussion and a report of a theoretical study [22] and X-ray analysis [21], supporting the bonding between metal and carbon, was recently published. The character of the metal to carbon bond of alkaline and thalhum fulminate is ionic, whereas fulminates of silver and mercury are covalent [20, 25], 

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HONC fulminic acid H2P2H2OS diphosphonic acid... 

Mercury Acetylenic compounds, chlorine, fulminic acid, ammonia, ethylene oxide, metals, methyl azide, oxidants, tetracarbonylnickel... 

Thermolysis of 4-methyl(4-phenyl)isoxazolin-5-one produced a-cyanophenylacetic acid <67JHC533). The pyrolysis of 3-methylisoxazoline-4,5-dione 4-oxime generated fulminic acid, which was trapped in a liquid N2 cooled condenser for further study. Pyrolysis of metal salts such as Ag or Na produced the corresponding highly explosive salts of fulminic acid 79AG503). Treatment of the oxime with amines generated bis-a,/3-oximinopropionamides (Scheme 65) <68AC(R)189). 

Isoxazole was first synthesized by Claisen in 1903 from propargylaldehyde diethyl acetal and hydroxylamine (03CB3664). It has also been obtained by addition of fulminic acid to acetylene in methanol-dilute sulfuric acid solution, by acidic hydrolysis of 5-acetoxyisoxazo-line, by reaction of /S-chloroacrolein or/3-alkoxyacrolein with hydroxylamine hydrochloride... 

HC(17)1, p. 53), and by retro-Diels-Alder reaction of the adduct from norbornadiene and fulminic acid <67AG(E)456). 

Isoxazole-3-carbaldehyde has been obtained as a minor product from the reaction of acetylene with a mixture of nitric oxide and nitrogen dioxide (61JOC2976). Although 3-aryl-4-formylisoxazoles have been synthesized in good yields from the reaction of benzonitrile Af-oxides with 3-(dimethylamino)-2-propen-l-one (71S433), the parent member of the series, isoxazole-4-carbaldehyde, has never been reported. It may possibly be obtained by the addition of fulminic acid to 3-(dimethylamino)-2-propen-l-one. 

Acetylene, fulminic acid (produced in ethanol - nitric acid mixtures), ammonia Acetic acid, acetone, alcohol, aniline, chromic acid, hydrocyanic acid, hydrogen sulphide, flammable liquids, flammable gases, or nitratable substances, paper, cardboard or rags Inorganic bases, amines Silver, mercury... 

Glycerol, ethylene glycol, benzaldehyde, sulphuric acid Acetylene, oxalic acid, tartaric acid, fulminic acid (produced in ethanol-nitric acid mixtures), ammonium compounds See alkali metals (above)... 

Of the few recent publications in this field two papers are noteworthy these are Cramer s report on the synthesis of 3,3 -diisoxazolyl in 60-70% yield from acetylene and nitrogen oxides and on the synthesis of a mixture of 5,5 -diisoxazolyls [34 35, R = Me2C(OH)] from fulminic acid and diacetyiene. ... 

Knall-saure, /. fulminic acid, -silber, n. fulminating silver, -welle, /. explosion wave, shock wave, -zucker, m. (Expl.) nitro-saccharose. -ziinder, m. detonator, -zund-mittel, n. detonating priming, knapp, a. close, tight, narrow scanty exact. Enappe, m. miner. 

It was first prepd by Palazzo by the interaction of hvdrazoic acid and fulminic acid at low temp. Can also be prepd by acidifying Na oxy-iso-tetrazole with dil sulfuric acid (Refs 1,2 4)... 

Mercury Acetylene, fulminic acid (produced in ethanol - nitric acid mixtures), ammonia... 

Fulminating gold Fulminating mercury Fulminating platinum Fulminating silver Fulminic acid Furan... 

Peroxides, organic Phosphorus (white) Potassium chlorate Potassium perchlorate Potassium permanganate Silver Acids (organic or mineral), avoid friction, store cold Air, oxygen Acids (see also chlorates) Acids (see also perchloric acid) Glycerol, ethylene glycol, benzaldehyde, sulphuric acid Acetylene, oxalic acid, tartaric acid, fulminic acid (produced in ethanol — nitric acid mixtures), ammonium compounds... 

Reaction of the silane with nitromethane is explosive, probably by intermediacy of fulminic acid (a dehydration product of nitromethane). 

The oxime (an isomer of ethylnitrolic acid ) decomposes gradually at ambient temperature, but explosively above 110°C [1], The product from treatment of nitromethane with strong sodium hydroxide solution at 50°C, followed by acidification and ether extraction, gave, after vacuum evaporation, a residue which exploded when air was admitted. On this occasion, a weekend elapsed between alkali and acid treatments, and it seems possible that formation of fulminic acid derivatives may have occurred [2], A 75 g sample of methazonic acid, from a preparation which had transiently overheated to 70°C, during the addition of nitromethane to sodium hydroxide solution, was stored for a week at — 15°C, then allowed to warm to room temperature. Twelve hours later it spontaneously detonated, destroying a fume hood. There is no evident cause for this explosion [3], It seems sensible to... 

See Fulminic acid (reference 2), also Sodium 3-methylisoxazolin-4,5-dione-4-oximate... 

Use of the mixed cone, acids to dissolve an organic residue caused a violent explosion. Nitric acid is a very powerful and rapid oxidant and may form unstable fulminic acid or polynitro compounds under these conditions. 

Nitrile oxides, RNCO, are derivatives of fulminic acid (R = H). They can be named as fulmido-substituted parent molecules, but usually their names are derived from corresponding nitriles, for example, benzonitrile oxide, mesitonitrile oxide, thiophene-2-carbonitrile oxide. 

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