Oxidation of ammonia with air

Modern processes for strong acid are based on direct oxidation of ammonia with air or oxygen, with the first two steps being similar to the weak acid process. Various processes exist allowing co-production of weak and strong acid. 

A technically important reaction is the oxidation of ammonia with air to nitrous oxides which are then converted into nitric acid. In this catalysis, losses are mainly caused by the formation of nitrogen as an oxidation product. 

All nitric acid plants are based on the same basic chemical operations 1) Oxidation of ammonia with air to give nitric oxide, 2) Oxidation of the nitric oxide to nitrogen dioxide and 3) Absorption in water to give a solution of nitric acid. The efficiency of the first step is favored by low pressure whereas that of the second step is favored by high pressure. These considerations, combined with economic reasons give rise to two types of nitric acid plants - single pressure and dual pressure97. 

Nitric acid is made industrially by oxidation of ammonia with air over platinum catalysts. The resulting nitric oxide is absorbed in water in the presence of air to... 

Nitric Acid.38 Nitric acid is made industrially by oxidation of ammonia with air over platinum catalysts.39 The resulting nitric oxide (Section 12-6) is absorbed in water in the presence of air to form N02, which is then hydrated. The normal concentrated aqueous acid (approximately 70% by weight) is colorless but often becomes yellow as a result of photochemical decomposition, which gives N02 ... 

E. C. C. Baly and H. M. Duncan studied the decomposition of ammonia by means of a hot platinum wire. Two types of ammonia may be prepared—an inactive and an active modification—which are decomposed to different extents by the same quantity of energy. The active form is obtained by the slow withdrawal of ammonia from a cylinder containing the compressed gas by warming the cone. aq. soln. and drying the gas by quicklime and by isothermal evaporation of the liquefied gas at its b.p. The inactive form is obtained by the rapid evaporation of the liquefied gas. The inactive gas slowly recovers its activity on remaining in contact with the liquefied gas. The same effect can be produced by gently warming the gas by means of a platinum wire heated at 200°. In order to observe these phenomena, the platinum wire must be activated in the same way as is customary in W. Ostwald s process for the catalytic oxidation of ammonia in air to nitric acid. Alternatively,... 

The most processes described above are also imder consideration as industrial relevant processes. Both methods, using acidic [54,55] and basic hydrolysis with the subsequent neutralization with an adequate mineral acid were developed, as well. The basic hydrolysis is performed with alcoholic KOH [56] and NaOH [57,58] solutions in the presence of aprotic solvents or in aqueous NaOH including the oxidation of contaminants with air obtaining an insoluble inorganic residue [59], The hydrolysis of PET in 7wt% ammonia solution results in a diammonium terephthalate yield of 80% after 30min reaction at 190°C [60]. 

Ostwald process A catalytic process used for the production of nitric acid by the oxidation of ammonia with aic The first step involves mixing air as a supply of oxygen and ammonia over a catalystat a temperature of700 C ... 

Allied-Signal Process. Cyclohexanone [108-94-1] is produced in 98% yield at 95% conversion by liquid-phase catal57tic hydrogenation of phenol. Hydroxylamine sulfate is produced in aqueous solution by the conventional Raschig process, wherein NO from the catalytic air oxidation of ammonia is absorbed in ammonium carbonate solution as ammonium nitrite (eq. 1). The latter is reduced with sulfur dioxide to hydroxylamine disulfonate (eq. 2), which is hydrolyzed to acidic hydroxylamine sulfate solution (eq. 3). 

Isatin (190) is a compound with interesting chemistry. It can be iV-acetylated with acetic anhydride, iV-methylated via its sodium or potassium salt and O-methylated via its silver salt. Oxidation of isatins with hydrogen peroxide in methanolic sodium methoxide yields methyl anthranilates (81AG(E)882>. In moist air, O-methylisatin (191) forms methylisatoid (192). Isatin forms normal carbonyl derivatives (193) with ketonic reagents such as hydroxylamine and phenylhydrazine and the reactive 3-carbonyl group also undergoes aldol condensation with active methylene compounds. Isatin forms a complex derivative, isamic acid (194), with ammonia (76JCS(P1)2004). 

It is available commercially from several routes including as a product from the manufacture of sodium nitrate from sodium chloride and nitric acid, and from a process involving the passage of ammonia and air over heated platinum and treating the nitric oxide so formed with oxygen. 

Nitric acid was known to alchemists in ancient times. Cavendish in 1784 synthesized the acid by applying an electric spark to humid air. Earlier in 1776, Lavoisier determined that the acid contained oxygen. In 1798, Milner prepared nitric acid from ammonia along with nitrogen oxides by oxidation of ammonia vapor over red-hot manganese dioxide. In 1816, Gay-Lussac and Berthollet established its composition. 

Ammonia Oxidation consists of treating anhydrous ammonia with air (or oxygen) at high temp and pressure and in the presence of a catalyst(such as Pt gauze) to obtain nitrogen oxides and eventually nitric acid. Installations for this treatment are called Ammonia Oxidation Plants , and nearly every large plant using nitric acid for the... 

Each c.c. of free space corresponds with 20 sq. cms. of catalyst surface. E. I. Orloff observed the oxidation of ammonia when mixed with air and passed over a heated copper gauze 4NH3-f-302 =2N2+6H20, with traces of nitrous and nitric acids—aniline, toluidine, and pyridine were oxidized in a similar way. W. W. Scott and W. D. Leech found that the conversion efficiency of cobalt oxide at 600°-800° is 79 3 per cent. This is augmented when about 3 per cent, of bismuth, or 10 to 12 per cent, of alumina, is used as... 

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