Nitric acid, properties

All thermodynamic data for air, the reaction gas mixture, and feed ammonia are taken from Ref.TDI (Section 3). Heat capacities for the various gas mixtures are calculated from the correlations in Ref.TD2. (Table E.1, p.538). Steam tables in Ref.TD3 are also used. Nitric acid properties are taken from Ref.TD4 (p.D-126 and D-77). Reaction equilibrium data are obtained from Refs. PT1 and PT2. 

Their cerium complex is reported as stable to air and acid (although decomposed by hot nitric acid), properties which are not consistent with those of the known bis([8]annulene)actinide(IV) complexes. The infrared spectrum of their complex is also inconsistent with the presence of a planar [8]annulene ligand. We have attempted to duplicate the synthesis of cerocene by the method of Kalsotra, Multani, and Jain and have not been able to reproduce their reported results. 

Lead dioxide is slightly soluble in concentrated nitric acid and concentrated sulphuric acid, and it dissolves in fused alkalis. It therefore has amphoteric properties, although these are not well characteri.sed since it is relatively inert. 

The chemical properties of nitric acid require us to consider the structure first. The vapour of pure nitric acid (i.e. anhydrous) is probably composed of molecules of hydrogen nitrate , which structurally is a resonance hybrid of such forms as ... 

Hence mercury is a poor reducing agent it is unlikely to be attacked by acids unless these have oxidising properties (for example nitric acid), or unless the acid anion has the power to form complexes with one or both mercury cations or Hg]", so altering the... 

Hughes, Ingold and Reed discussed the relative merits of the and e3 schemes as mechanisms for nitration by considering the properties of acetic acid, nitromethane, nitric acid and sulphuric acid as media for the reaction. The facts have already been discussed ( 2.2.3, 2.2.4, 2.3.2, 2.4.2, 2.4.3, 3-2). 

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. 

The cooled, dried chlorine gas contains - 2% HCl and up to 10% O2, both of which are removed by Hquefaction. A full scale 600-t/day plant was built by Du Pont ia 1975. This iastaHatioa at Corpus Christi, Texas operates at 1.4 MPa (13.8 atm) and 120—180°C and uses tantalum-plated equipment and pipes. Oxidation of HCl Chloride by JSHtricHcid. The nitrosyl chloride [2696-92-6] route to chlorine is based on the strongly oxidi2iag properties of nitric acid... 

Table 1 Hsts some of the physical properties of duoroboric acid. It is a strong acid in water, equal to most mineral acids in strength and has a p p o of —4.9 as compared to —4.3 for nitric acid (9). The duoroborate ion contains a neady tetrahedral boron atom with almost equidistant B—F bonds in the sohd state. Although lattice effects and hydrogen bonding distort the ion, the average B—F distance is 0.138 nm the F—B—F angles are neady the theoretical 109° (10,11). Raman spectra on molten, ie, Hquid NaBF agree with the symmetrical tetrahedral stmcture (12).

Lead Fluoride. Lead difluoiide, Pbp2, is a white oithorhombic salt to about 220°C where it is transformed into the cubic form some physical properties ate given in Table 1. Lead fluoride is soluble in nitric acid and insoluble in acetone and ammonia. It is formed by the action of hydrofluoric acid on lead hydroxide or carbonate, or by the reaction between potassium fluoride and lead nitrate. 

Table 1. Physical Properties of Nitric Acid Solutions at 20°C...

Thermo dynamic data for nitric acid are given ia Table 2. Properties for the ternary systems sulfuric acid—nitric acid—water (5,14) and magnesium nitrate—nitric acid—water (11,15—17) used ia processes for concentrating nitric acid are available. 

Table 2. Thermodynamic Properties of Nitric Acid and Its Hydrates...

Acidic Properties. As a typical acid, it reacts readily with alkaUes, basic oxides, and carbonates to form salts. The largest iadustrial appHcation of nitric acid is the reaction with ammonia to produce ammonium nitrate. However, because of its oxidising nature, nitric acid does not always behave as a typical acid. Bases having metallic radicals ia a reduced state (eg, ferrous and staimous hydroxide becoming ferric and stannic salts) are oxidized by nitric acid. Except for magnesium and manganese ia very dilute acid, nitric acid does not Hberate hydrogen upon reaction with metals. 

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). 

Esters of nitro alcohols with primary alcohol groups can be prepared from the nitro alcohol and an organic acid, but nitro alcohols with secondary alcohol groups can be esterified only through the use of an acid chloride or anhydride. The nitrate esters of the nitro alcohols are obtained easily by treatment with nitric acid (qv). The resulting products have explosive properties but are not used commercially. 

The corrosion behavior of tantalum is weU-documented (46). Technically, the excellent corrosion resistance of the metal reflects the chemical properties of the thermal oxide always present on the surface of the metal. This very adherent oxide layer makes tantalum one of the most corrosion-resistant metals to many chemicals at temperatures below 150°C. Tantalum is not attacked by most mineral acids, including aqua regia, perchloric acid, nitric acid, and concentrated sulfuric acid below 175°C. Tantalum is inert to most organic compounds organic acids, alcohols, ketones, esters, and phenols do not attack tantalum. 

Hydrolysis of solutions of Ti(IV) salts leads to precipitation of a hydrated titanium dioxide. The composition and properties of this product depend critically on the precipitation conditions, including the reactant concentration, temperature, pH, and choice of the salt (46—49). At room temperature, a voluminous and gelatinous precipitate forms. This has been referred to as orthotitanic acid [20338-08-3] and has been represented by the nominal formula Ti02 2H20 (Ti(OH). The gelatinous precipitate either redissolves or peptizes to a colloidal suspension ia dilute hydrochloric or nitric acids. If the suspension is boiled, or if precipitation is from hot solutions, a less-hydrated oxide forms. This has been referred to as metatitanic acid [12026-28-7] nominal formula Ti02 H2O (TiO(OH)2). The latter precipitate is more difficult to dissolve ia acid and is only soluble ia concentrated sulfuric acid or hydrofluoric acid. 

Barium nitrate is prepared by reaction of BaCO and nitric acid, filtration and evaporative crystallization, or by dissolving sodium nitrate in a saturated solution of barium chloride, with subsequent precipitation of barium nitrate. The precipitate is centrifuged, washed, and dried. Barium nitrate is used in pyrotechnic green flares, tracer buUets, primers, and in detonators. These make use of its property of easy decomposition as well as its characteristic green flame. A small amount is used as a source of barium oxide in enamels. 

For the properties of these compounds, see Esters, organic. For esters of inorganic acids, see the articles on nitric acid, phosphoric acids, sulfuric acid, etc. 

Figure 8.1 Effect of pH on corrosion of 1100-H14 alloy (aluminum) by various chemical solutions. Observe the minimal corrosion in the pH range of 4-9. The low corrosion rates in acetic acid, nitric acid, and ammonium hydroxide demonstrate that the nature of the individual ions in solution is more important than the degree of acidity or alkalinity. (Courtesy of Alcoa Laboratories from Aluminum Properties and Physical Metallurgy, ed. John E. Hatch, American Society for Metals, Metals Park, Ohio, 1984, Figure 19, page 295.)...

Figure 4-12. Duty range for turbocompressors in nitric acid plants. The diagram refers to atmospheric air and gases with similar properties, such as nitrous gas (A = axial, R = radial flow compressor).

The chemical resistance of polyethylene is, to a large measure, that expected of an alkane. It is not chemically attacked by non-oxidising acids, alkalis and many aqueous solutions. Nitric acid oxidises the polymer, leading to a rise in power factor and to a deterioration in mechanical properties. As with the simple alkanes, halogens combine with the hydrocarbon by means of substitution mechanisms. 

A list of danger categories is given in Table 14.2. Note that chemicals may possess several hazards, e.g. nitric acid is classed as both an oxidizer and a conosive. If a chemical is not in one of these categories it is not generally considered to be dangerous. If the hazards of a new chemical have not been established it should be labelled Caution - substance not yet fully tested . Mixtures can be classified either from results from tests on the preparation, or by calculation to predict the healtli effects of the product based on the properties of individual components and tlieu concentration in the mixture. Preparations need to be classified for both physico-chemical and health effects but, to date, not for environmental effects. 

The 17% ferritic steels are easier to fabricate than the martensitic grades. They are used extensively in equipment for nitric acid production. The oxygen- and sulfur-resistant 30% chromium steel can be used at temperatures up to 1150°C but only for lightly loaded and well-supported furnace items because of its poor creep and brittlement properties when equipment is down to ambient temperatures [18]. 

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