Nitric Acid and Ammonium Nitrate

The catalytic oxidation of ammonia by air over platinum gauze at 900 °C gives nitric oxide (reaction 9.12), which is then oxidized to nitric acid by air and liquid water in a nitrous gas absorber (reactions 9.13 and 9.14)  

For the same reason, the gas leaving the catalyst should be substantially free of NH3 otherwise, reaction 9.17 will occur while the gas is still hot  

Note that the most important function of the catalyst, here and in many other instances, is not so much its overall catalytic activity as its selectivity in promoting the one reaction (9.12) over its competitors. In biological systems, enzymes have evolved to extraordinary degrees of selectivity often, they will catalyze one specific biochemical reaction and no others. 

The nitrous gas absorption step (reactions 9.13 and 9.14) is slow, especially if concentrated HNO3 is required, since cooling to 2°C is then necessary. Consequently, large countercurrent towers of stainless steel are needed, with associated high capital cost. The recovery of the heat of reaction of this step is inefficient because of the low temperature of the source gases that must be maintained. It has been suggested that the energy of reaction 9.12 could be more effectively recovered if it is run in a fuel cell (see Exercise 15.8). 

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 HNO3, and the NH4NO3 solution is evaporated to a liquid melt ( 8% H2O) 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 NH4NO3. 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. 

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Nitrates those gases and aerosols that have origins in the gas-to-aerosol conversion of nitrogen oxides, e.g., NOj of primary interest are nitric acid and ammonium nitrate. Ammonium nitrate is very hygroscopic so its contribution to visibility impairment is magnified in the presence of water vapor. 

Stein et al. [673] have described a simplified, sensitive, and rapid method for determining low concentrations of cadmium, lead, and chromium in estuarine waters. To minimise matrix interferences, nitric acid and ammonium nitrate are added for cadmium and lead only nitric acid is added for chromium. Then 10,20, or 50 pi of the sample or standard (the amount depending on the sensitivity required) is injected into a heated graphite atomiser, and specific atomic absorbance is measured. Analyte concentrations are calculated from calibration curves for standard solutions in demineralised water for chromium, or an artificial seawater medium for lead and cadmium. 

Dave and co-workers have reported a successful synthesis of 2,2,4,4-tetranitroadamantane (117) which uses the mono-protected diketone (113) as a key intermediate. In this synthesis (113) is converted to the oxime (114) and then treated with ammonium nitrate and nitric acid in methylene chloride to yield the em-dinitro derivative (115). This nitration-oxidation step also removes the acetal-protecting group to leave the second ketone group free. Formation of the oxime (116) from ketone (115), followed by a similar nitration-oxidation with nitric acid and ammonium nitrate, yields 2,2,4,4-tetranitroadamantane (117). In this synthesis the protection strategy enables each carbonyl group to be treated separately and thus prevents the problem of internal nitroso dimer formation. 

The reaction of hexamine dinitrate (241) with 98% nitric acid at —30°C, followed by quenching with aqueous sodium nitrate, yields the nitrosamine (244). When the same reaction is cautiously quenched with ethanol the ethoxyether (245) is obtained. Treatment of the ethoxyether (245) with cold absolute nitric acid yields the bicyclic ether (246). ° Treatment of any of the cyclic nitramines (242)-(246) with nitric acid and ammonium nitrate in acetic anhydride yields RDX. ° Hexamine dinitrate is often used in low temperature nitrolysis experiments in order to avoid the initial exotherm observed on addition of hexamine to nitric acid. 

According to the investigations of T. Urbanski and Szyc-Lewanska [56], cyclonite is also formed by the action of nitric acid and ammonium nitrate on hexamethylene-triperoxidediamine which is discussed on p. 225. 

N-Nitration Tetryl RDX HMX Mixture of nitric and sulfuric acids Nitric acid and ammonium nitrate Nitric acid and ammonium nitrate... 

Ion- Exchange Unit This unit would probably service all three plants (ammonia, nitric acid and ammonium nitrate) in the chemicals complex, and would consist of a series of packed beds containing various organic polymer resins for the removal of unwanted divalent and monovalent ions. 

Iron and steel are dissolved in 1 1 nitric acid, the solution evaporated to dryness and the residue taken up with concentrated hydrochloric acid until all the silica is rendered insoluble. The solution containing the phosphoric and hydrochloric acids is evaporated to dryness once more to get rid of the latter acid, and the residue then taken up with nitric acid and ammonium nitrate solution and precipitated with ammonium molybdate. 

Prepare a complete list, with sample form sheets, of all cost-accounting records which should be maintained in a large plant producing ammonia, nitric acid, and ammonium nitrate. Explain how these records are used in recording, summarizing and interpreting costs and profits. 

The nitrating agents for the manufacture of explosives via C-nitration, 0-nitration, or N-nitration are mixtures of nitric and sulfuric acids, except for RDX and HMX where a mixture of nitric acid and ammonium nitrate is used [4]. 

For the same reason special prominence has been given to the new synthetic processes for making ammonia directly from its component elements, and its subsequent oxidation to nitric acid and ammonium nitrate by catalytic processes, which are now being-worked in Germany on a very large scale. 

R.M. Harrison and H.A. McCartney, Some measurements of ambient air pollution arising from the manufacture of nitric acid and ammonium nitrate fertilizer. Atmos. Envir. 13,1105 (1979). 

As a consequence of its recent development the petrochemical industry is relatively much younger than the major inorganic chemicals industry. However, one can easily be misled by the classification of products that are termed petrochemical . Basically a petrochemical is derived directly or indirectly from a petroleum or natural gas fraction. It may be organic, such as ethylene, benzene, or formaldehyde, or it may be inorganic, such as ammonia, nitric acid, and ammonium nitrate (Chap. 11). So a petrochemical is not synonymous with an organic chemical, although most petrochemicals are also organic chemicals. 

Andrews SPS. (1977) Modem processes for the production of ammonia, nitric acid and ammonium nitrate. In Thompson R, editor. The modem inorganic chemicals industry the proceedings of a symposium organised by the Inorganic Chemicals Group of the Industrial Division of the Chemical Society, London, UK, March 31-April 1, 1977 (Vol. 31). Royal Society of Chemistry, London, UK, p 201-231. 

III. Destruction with Nitric Acid and Ammonium Nitrate... 

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