Nitric acid materials used

Materials Ferrous sulphate, ammonium sulphate, concentrated nitric acid, materials used in testing for ferric and for ammonium compounds. 

Oxidizing Properties. Nitric acid is a powerful oxidizing agent (electron acceptor) that reacts violentiy with many organic materials (eg, turpentine, charcoal, and charred sawdust) (19,20). The concentrated acid may react explosively with ethanol (qv). Such oxidizing properties have had military appHcation nitric acid is used with certain organics, eg, furfuryl alcohol and aniline, as rocket propellant (see Explosives AND PROPELLANTS). 

The materials of constmction for the mixing device and storage vessels must be selected carefully. Glass (qv), polytetrafluoroethylene, or certain kiads of stainless steels are usually used. Glass must be pickled with nitric acid before use. 

The rate of a nitration is fastest at the start of a reaction when a large excess of nitric acid is present. As the reaction progresses the water formed during nitration dilutes the mixed acid and slows the rate of reaction, and as such, it is common towards the end of a nitration, when most of the substrate has reacted, to heat the reaction to completion. This dilution of the acid with water is an important point and the amount of sulfuric acid used should be enough to take up all the water formed during the reaction otherwise, nitration may be incomplete and result in an unfavourable mixture of product and starting material. Increased amounts of water in mixed acid rapidly reduce the concentration of nitronium ions. When concentrated nitric acid is used for the nitration of some of the more reactive substrates a large excess of sulfuric is often used to compensate for the water present. 

Some nitric acid is used for the manufacture of explosives and chemicals, but much is converted on-site to the potentially explosive high nitrogen fertilizer ammonium nitrate (Section 2.11). Ammonia gas from the Haber plant is absorbed in aqueous HN03, and the NH4N03 solution is evaporated to a liquid melt (< 8% H20) for crystallization, but care must be taken to keep the pH of the solution above about 4.5 and to exclude any material (chlorides, organic compounds, metals) that might catalyze the explosive decomposition of NH4N03. It is also wise to keep the melt mass low and to vent it to avoid pressure buildup. The solid product should be stored well away from the main plant. 

Almost without exception the nitro compounds and nitric acid esters used as explosives are toxic. The degree of toxicity varies widely with the material in question, but most are capable of causing acute distress if taken orally. Nitroglycerin has a small medical use as a vasodilator. 

The sensitivity of AAS is usually sufficieut to allow determinatiou of these elemeuts iu steels after simply dissolving the sample. Most often a mixtme of hydrochloric and nitric acids is used, but sometimes sulfuric aud phosphoric acids with several drops of nitric acid to facilitate oxidation are preferred. In any case, the volumes of acids in all the solutions sprayed must be kept constant, because generally the acids have a depressive effect. For the analysis of organic materials, plants, fertihzers, and so on, the ash is often digested with acids and the undissolved residue filtered off. 

It should be stable in the presence of chemical agents used in the process, such as nitric acid. Solvents used for radioactive materials should also have good radiation stability. 

For example, in 3 h at 180-190° there are produced from dodecane 40% of mononitro-dodecanes, together with 43% of unchanged material and small amounts of di- and poly-nitro compounds. There is more dinitration if a longer residence time or a greater excess of nitric acid is used.150... 

The purified pertechnetate eluted from the column was detected and quantified with a flow through scintillation detector using a lithium glass solid scintillator. This scintillator material exhibited excellent stability in the strong nitric acid solutions used for pertechnetate elution. 

Reyad et al carried out surface modification of oil fly ash (OFA), a byproduct generated by oil power plants, by chemical treatment. A mixture of sulfuric and nitric acids was used to modify the surface in order to attach a carboxylic functional group to the surface of OFA. The goal of surface modification of OFA is to make its surface more compatible with non-polar polymers in order to produce OFA/polymer composite materials with improved dispersion of OFA, and to increase OFA surface area in order to support its use as adsorbent materials in adsorptive separation and purification applications. Different acid compositions were used in their study for the treatment by gradually increasing the nitric add concentration from 0 to 20%. They also examined the effect of oxidation on surface modification by introducing air to enhance the oxidation of OFA. 

Kirchheiner, R., Heubner, U., Hoffmann, P. (1989), Increasing the lifetime of nitric acid equipment using improved stainless steels and nickel alloys. Material Perf., Vol. 28, No. 9, 58-67. 

Use spill-control pillows to contain the spill. Wear coveralls, rubber apron, gloves, face protection, rubber boots, and, if necessary, respiratory protection (especially for spills of hydrochloric and nitric acids). Materials left after cleanup is completed should be handled as hazardous chemical wastes. Complete cleanup by washing the area of the spill with a detergent solution, and have any damage repaired. 

Nitrations are usually carried out at comparatively low temperatures at higher temperatures there may be loss of material because of the oxidising action of the nitric acid. For substances which do not nitrate readily with a mixture of concentrated nitric and sulphuric acids ( mixed acid ), the intensity of the reaction may be increased inler alia by the use of fuming sulphuric acid (containing up to 60 per cent, of sulphur trioxide) or by fuming nitric acid. Thus nitrobenzene is converted by a mixture of fuming nitric acid and concentrated sulphuric acid into about 90 per cent, of wi-dinitrobenzene and small amounts of the o- and p-isomers the latter are eliminated in the process of recrystallisation ... 

Acid—Base Chemistry. Acetic acid dissociates in water, pK = 4.76 at 25°C. It is a mild acid which can be used for analysis of bases too weak to detect in water (26). It readily neutralizes the ordinary hydroxides of the alkaU metals and the alkaline earths to form the corresponding acetates. When the cmde material pyroligneous acid is neutralized with limestone or magnesia the commercial acetate of lime or acetate of magnesia is obtained (7). Acetic acid accepts protons only from the strongest acids such as nitric acid and sulfuric acid. Other acids exhibit very powerful, superacid properties in acetic acid solutions and are thus useful catalysts for esterifications of olefins and alcohols (27). Nitrations conducted in acetic acid solvent are effected because of the formation of the nitronium ion, NO Hexamethylenetetramine [100-97-0] may be nitrated in acetic acid solvent to yield the explosive cycl o trim ethyl en etrin itram in e [121 -82-4] also known as cyclonit or RDX. 

Nitric Phosphate. About 15% of worldwide phosphate fertilizer production is by processes that are based on solubilization of phosphate rock with nitric acid iastead of sulfuric or phosphoric acids (64). These processes, known collectively as nitric phosphate or nitrophosphate processes are important, mainly because of the iadependence from sulfur as a raw material and because of the freedom from the environmental problem of gypsum disposal that accompanies phosphoric acid-based processes. These two characteristics are expected to promote eventual iacrease ia the use of nitric phosphate processes, as sulfur resources diminish and/or environmental restrictions are tightened. 

The U.S. domestic commercial potassium nitrate of the 1990s contains 13.9% N, 44.1% I+O, 0—1.8% Cl, 0.1% acid insoluble, and 0.08% moisture. The material is manufactured by Vicksburg Chemical Co. using a process developed by Southwest Potash Division of AMAX Corp. This process uses highly concentrated nitric acid to catalyze the oxidation of by-product nitrosyl chloride and hydrogen chloride to the mote valuable chlorine (68). The much simplified overall reaction is... 

Cellulose nitrate also has widespread use as an adhesive and coating material. Whereas stabilizers are added to products, eg, sodium carbonate as a neutralizer, many conservators are hesitant to use cellulose nitrate materials because of the inherent instabiUty and the dangers to the object from nitric acid, formed when the nitric oxide combines with moisture. 

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