Nitric acid, anhydrous fuming

All the isomers are crystalline, pale yellow products and are poisonous. In addition, sym-trinitrobenzene causes severe irritation of the skin. 1,3,5-Trinitrobenzene can be formed in poor yield by the action of a mixture of anhydrous nitric acid and fuming sulphuric acid on m- dinitrobenzene, the 1,2,4-isomer also being formed in a very small quantity. The 1,2,3-isomer can be obtained only by indirect methods. 

Direct nitration of m- dinitrobenzene. Hepp [30] who first used this method in 1887, reported that he was able to nitrate only two thirds of the dinitrobenzene used, in spite of using anhydrous nitric acid and fuming sulphuric acid. 

NOTE. Anhydrous nitric acid (white fuming nitric acid) is a colorless liquid, bp 83°C It is estimated that the nitric acid obtained in this preparation is at least 99.5-100% pure. If it is necessary to store the distillate, remove the acid from the collar of the still (Pasteur pipet) and place it in a 1.0-mL conical mol fitted with a glass stopper. It may be necessary to slightly bend the end of the pipet in aflame so that it can reach the collar of a still that does not have a side port. The anhydrous nitric acid is colorless or faintly yellow. 

Hexafluorophosphoric Acid. Hexafluorophosphoric acid (3) is present under ambient conditions only as an aqueous solution because the anhydrous acid dissociates rapidly to HF and PF at 25°C (56). The commercially available HPF is approximately 60% HPF based on PF analysis with HF, HPO2F2, HPO F, and H PO ia equiUbrium equivalent to about 11% additional HPF. The acid is a colorless Hquid which fumes considerably owiag to formation of an HF aerosol. Frequently, the commercially available acid has a dark honey color which is thought to be reduced phosphate species. This color can be removed by oxidation with a small amount of nitric acid. When the hexafluorophosphoric acid is diluted, it slowly hydrolyzes to the other fluorophosphoric acids and finally phosphoric acid. In concentrated solutions, the hexafluorophosphoric acid estabUshes equiUbrium with its hydrolysis products ia relatively low concentration. Hexafluorophosphoric acid hexahydrate [40209-76-5] 6 P 31.5°C, also forms (66). This... 

Fluoronaphthalene [321-38-0] is prepared from 1-naphthylamine by the Balz-Schiemaim reaction in 52% yield or by diazotization in anhydrous hydrogen fluoride in 82% yield. Electrophilic substitution occurs at the 4-position, eg, nitration with fuming nitric acid in acetic acid gave 88% yield of l-fluoro-4-nitro-naphthalene [341 -92-4]. 

Copper, chromium, iron, most metals or their salts, any flammable liquid, combustible materials, aniline, nitromethane Fuming nitric acid, oxidizing gases Acetylene, ammonia (anhydrous or aqueous)... 

Stress-corrosion cracking (Section 8.10) New metal/environment combinations which produce stress-corrosion cracking are continually being found. Combinations discovered in service in recent years include titanium in red fuming nitric acid carbon steel in liquid anhydrous ammonia and in... 

Under a gentle stream of nitrogen and with stirring, the flask is charged with 400 ml. of methylene chloride, 41 ml. (65.5 g., 1.00 mole) of red fuming nitric acid (95%), and 22 ml. (22 g., 1.10 moles) of cold, liquid, anhydrous hydrogen fluoride (Note 5). 

Other preparations and isolations. If damp methylenedi(nitroformamide) is allowed to stand for several days, the odor of formic acid is noticed, and MEDINA can be isolated from the residue (Ref 11, p 14). The details of scale-up to 150 lb batches, including exp details and flow sheets, and further scale-up with the aim of prodn of 1000 lbs are given. The report describes a fume-off and fire which occurred during the S3rd run. The cause was attributed to a stuck valve which allowed nitric acid to build up in the reactor (Ref 13, p 57). In Ref 16, p 73 there are cost analysis data for pilot plant and large scale prodn, flow sheet for a proposed coml plant, and material balances. The action of acet anhydr on N,Nf-bis(hydroxy-methyl)MEDlNA regenerates MEDINA (Ref 6) the diNa salt of N. N trinitrotrimethylene-diamine, on warming with me ale, ppts the Na salt of MEDINA... 

Other Uses of Nitric Acid. As mentioned earlier, fuming nitric acid (FNA) when mixed with ale, toluene or acet anhydr will cause an expln. However, there are many other uses for FNA in energetic materials technology. As either red fuming nitric acid (RFNA) or as nitrogen tetrox-ide, it is used extensively as the oxidizer in pro-pint systemsnfor ram-jets, jet motors, space rockets and other missiles (Refs 37, 38 39). See also under Liquid Propellants in Vol 7, L24-Rff... 

A. Dinitrodurene.—A solution of 13.4 g. (0.1 mole) (Notes 1,2) of durene (p. 32) in 100 cc. of chloroform is added to 75 cc. of concentrated sulfuric acid in an 800-cc. beaker provided with a thermometer and an efficient mechanical stirrer. The mixture is cooled to io°, and 16 g. (10.7 cc.) of fuming nitric acid (sp. gr. 1.5) (Note 3) is added drop by drop, with stirring, from a 125-cc. separatory funnel, the mixture being cooled in an ice-salt bath and the nitric acid added at such a rate that the temperature does not rise above 50° (about fifteen minutes is required for the addition). As soon as all the acid has been added the mixture is poured into a separatory funnel, the sulfuric acid layer is removed and the upper chloroform layer is immediately (Note 4) run into 500 cc. of 10 per cent sodium carbonate solution. The sulfuric acid layer is discarded because it contains very little dinitrodurene. Four portions are nitrated and the combined chloroform solutions are washed twice with 2.5 per cent sodium carbonate solution, dried over night with 30 g. of anhydrous calcium chloride, filtered, and the chloroform distilled off until crystals of dinitrodurene begin to appear. At this point four times the volume of hot 95 per cent ethyl alcohol is added (about... 

A large number of reagents are available for the preparation of nitro PAHs. These include fuming nitric acid in acetic acid (20) or acetic anhydride (13), sodium nitrate in trifluoroacetic acid (21) or trifluoroacetic acid and acetic anhydride (17), dinitrogen tetroxide in carbon tetrachloride (22), sodium nitrate in trimethyl phosphate and phosphorus pentoxide (23), and nitronium tetrafluoroborate in anhydrous acetonitrile (24). Alternative approaches must be used to synthesize nitro PAHs substituted at positions other than the most reactive carbon. For instance,... 

The reaction of alkynes with nitric acid or mixed acid is generally not synthetically useful. An exception is the reaction of acetylene with mixed acid or fuming nitric acid which leads to the formation of tetranitromethane. A modification to this reaction uses a mixture of anhydrous nitric acid and mercuric nitrate to form trinitromethane (nitroform) from acetylene. Nitroform is produced industrially via this method in a continuous process in 74 % yield. " The reaction of ethylene with 95-100 % nitric acid is also reported to yield nitroform (and 2-nitroethanol). The nitration of ketene with fuming nitric acid is reported to yield tetranitromethane. Tetranitromethane is conveniently synthesized in the laboratory by leaving a mixture of fuming nitric acid and acetic anhydride to stand at room temperature for several days. ... 

This unusual process known as the W-method was discovered in Germany by Wolfram and involves the condensation of the potassium salt of sulfamic acid with formaldehyde to form the heterocycle (238) followed by treatment with nitric acid. The extreme sensitivity of (238) to hydrolysis means that nitrolysis has to be conducted under anhydrous conditions using sulfur trioxide or phosphorous pentoxide " dissolved in fuming nitric acid. The yield of RDX from the W-method is 80-90 %. 

Nickel nitrate hexahydrate may be prepared by several methods based on the reaction of dilute nitric acid on nickel powder, nickel oxide or nickel carbonate. The reaction is exothermic and requires controlled cooling during production. The hexahydrate can be dehydrated to anhydrous salt by treatment with fuming nitric acid. 

OB -38.2% shiny crystals (from cone nitric acid), platelets and prisms, containing 1 mole H20 (from w), mp ca 105° (loses water) of hydrated compd, 186° of anhydrous,darkens at 200° puffs off on rapid heating sol in water, ale or eth, si sol in benz. Prepd by heating diazoaminobenzoic acid with coned nitric acid, or reacting 3-amino-benzoic acid with fuming nitric acid (Ref 1). It is quantitatively precipitated by a phenylacridine soln (Ref 3)... 

Nitric acid is a strong oxidizing agent. Organic substances may ignite when reacted with the concentrated acid (fuming and anhydrous). Nitric acid vapour irritates the respiratory tracts. If nitric acid gets on one s skin, it causes serious... 

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