Fuming acid

Nitric 304 L stainless steel Must use low-carbon (or stabilized grade) if welded not for fuming acid concentrations above 65.5°C... 

Uses. Since 1947, 70 to 85% of the annual USA production of nitric acid has gone into the production of NH4 nitrate fertilizer, initially in the form of solid prills currently, increasing amounts have been supplied mixed with excess ammonia and/or urea as aqueous nitrogen solution for direct application to the soil. Some 15% is used in explsj (nitrates nitro compds), and about 10% is consumed by the chemical industry. As the red fuming acid or as nitrogen tetroxide, nitric acid is used extensively as the oxidizer in proplnts for rocketry. It is estimated that current USA capacity for nitric acid is in excess of 10 million tons (Refs 30, 34, 36 37)... 

S, starch, lignite, charcoal, tar, naphthalene, etc), picrates, NG, NC resins, etc. Some expls even contained fuming acid, eg, Emmens Acid and Emmensite... 

Nitric acid and especially fuming acid is a strong oxidant and nitrating agent, especially when it is combined with sulphuric acid (formation of an electrophilic species). The dangers of the reactions which involve this compound are linked to the exothermicity of the reactions and the eventual formation, particularly in an aromatic series, of nitrated species that can be very unstable in some cases. 

Cyclopentadiene reacts explosively in the presence of fuming acid even in inert gas. The danger is aggravated by sulphuric acid. 

Extracts of these fat samples were treated with sodium sulfate-concentrated sulfuric acid mixture and fuming acid by the method described by Schechter et al. 5) in order to separate the organic-chlorine compound from the fatty materials. An infrared spectrum from 7 to 15 microns on carbon disulfide solutions of the residues from the fat qualitatively identified the organic-chlorine compound as toxaphene. All the bands of toxaphene in this spectral region were plainly seen in the treated steer extract, whereas none of the absorption bands were visible in the untreated steer extract. 

The oxidising power and hazard potential of nitric acid increases progressively with increase in strength from the cone, acid (70 wt%) through fuming acids (above... 

Boron (finely divided forms) reacts violently with cone, acid and may attain incandescence. The vapour of phosphorus, heated in nitric acid in presence of air, may ignite. Boron phosphide ignites with the cone, acid [1], Silicon crystallised from its eutectic with aluminium reacts violently with cone, acid [2], arsenic may react violently with the fuming acid, and finely divided carbon similarly with cone, acid [3], Use of cone, acid to clean a stainless steel hose contaminated with phosphorus led to an explosion [4],... 

Phosphine ignites in cone, nitric acid and addition of warm fuming nitric acid to phosphine causes explosion [1], Phosphonium iodide ignites with nitric acid, and ethylphosphine explodes with fuming acid [2], Tris(iodomercuri)phosphine is violently decomposed by nitric acid or aqua regia [3],... 

A cracked winchester of cone, acid leaked into sawdust packing and caused a fire [1]. A similar incident was involved in a freight-plane crash [2], Fuming acid, leaking from a cracked bottle, ignited a wooden truck [3], A retrospective survey on nitric acid packed in sawdust reveals an incident before 1894 [4],... 

Trinitrobenzoic acid has been prepared by heating trinitrotoluene with fuming acid in a sealed tube to ioo°, for two weeks,1 the oxidation being only partial. It can also be prepared by heating trinitrotoluene under a reflux condenser, with a mixture of 5 parts of concentrated nitric acid and 10 1 Ber. 8, a 3 (1870). 

For example, treating petroleum distillates with sulfuric acid is generally applied to dissolve unstable or colored substances and sulfur compounds as well as to precipitate asphaltic materials. When drastic conditions are employed, as in the treatment of lubricating fractions with large amounts of concentrated acid or when fuming acid is used in the manufacture of white oils, considerable quantities of petroleum sulfonic acids are formed ... 

In the Kostevitch method a sample of explosive (about O.lg) is introduced into a small glass bulb (volume=ca 3.5cc), resembling in appearance that used for weighing fuming acids, but made from a larger diameter tube in order... 

The catalyst usually employed for sulfuric acid alkylation is 98% sulfuric acid, although concentrations as high as 100% are equally satisfactory. The use of fuming acids is not desirable since the excess sulfur trioxide reacts with isobutane and does not serve as a catalyst. It is possible to use sulfuric acid of concentrations as low as 90%, but the use of these weaker acids has an adverse effect on the alkylate quality and catalyst life. 

Direct sodium hydroxide neutralization of the sulfonation mixture resulting from the fuming acid sulfonation of dodecyl benzene gives a product which, upon drying, contains approximately 50% active detergent and 50% sodium sulfate. If a higher active content is desired, the unreacted sulfuric acid can be partially removed from the sulfonation mixture by the addition of about 10 volume % of water at the end of sulfonation. By this means the active content of the dried detergent can be increased to about 85%, but unless the heat of dilution is carefully controlled, the hydrolysis of undesirable by-products in the spent acid may lead to unpleasant odors in the dried product. 

In the fifteenth and sixteenth centuries the alchemists obtained sulphuric acid in this manner, frequently aiding the process by the addition of silica, and the process was worked on a commercial scale until the end of the nineteenth century. From the fact that much of the fuming acid was distributed from Nordhausen in Prussia, the name Nordhausen sulphuric acid originated, but little if any of the acid was manufactured in this town.6... 

A thermometric method of evaluating the fuming acid consists in adding excess of standard 80 per cent, sulphuric acid and titrating back with the fuming acid the temperature of the solution rises with each addition of the fuming acid until the water content of the standard is exhausted.3... 

Physical Properties of Sulphuric Acid.—The pure product obtained by evaporation or distillation whether of a dilute or a fuming acid contains as a maximum approximately 98-4 per cent, of H2S04, the actual figure varying slightly with the pressure.7 At extremely low... 

The tests to be made are those given under Fuming Hydrochloric Acid. But, instead of using 10 gm. of the fuming acid, use 35 gm. of the 10 per cent acid. 

The indicated proportions of fuming nitric acid and concentrated acid give as good results as fuming acid alone. The addition of the concentrated acid first does not work well. 

This product melts at 145° to 147° C., and is easily soluble in organic solvents. In concentrated sulphuric acid it gives a dark red solution with green fluorescence in the fuming acid the colour is deep green. With p-n itrobenzaldekyde ... 

This body forms blue-black prisms, M.pt. 241° to 242° C., giving a violet-red solution in chloroform, a green solution in concentrated sulphuric acid, and a violet-red solution in the fuming acid. 

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