LYCOS RETRIEVER 
Nitric Acid: Ammonia
built 629 days ago
Nitric acid is made in three stages. The first step is the oxidation of ammonia gas with air to form nitric oxide. In order to achieve a high conversion efficiency, this is normally carried out at pressure over a platinum-rhodium catalyst. The nitric oxide is cooled and further oxidised to form nitrogen dioxide, which is then absorbed in water to nitric acid.
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Nitric acid is a strong oxidizing agent. It ionizes readily in solution, forming a good conductor of electricity. It reacts with metals, oxides, and hydroxides, forming nitrate salts. Chief uses of nitric acid are in the preparation of fertilizers, e.g., ammonium nitrate, and explosives, e.g., nitroglycerin and trinitrotoluene (TNT). It is ... used in the manufacture of chemicals, e.g., in making dyes, and in metallurgy, ore flotation, etching steel, photoengraving, and reprocessing of spent nuclear fuel. It is produced chiefly by oxidation of ammonia (the Ostwald process).
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Nitric acid can be prepared in the lab by the distillation of a mixture of an alkali-metal nitrate and concentrated sulfuric acid. Industrially, it is produced by oxidizing ammonia to nitrogen monoxide, oxidizing this to nitrogen dioxide, and reacting nitrogen dioxide with water. The first reaction – the oxidation of ammonia – is catalyzed by platimum or platinum/rhodium in the form of a thin wire gauze.
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Sulfur dioxide ... interacts with NOx to form nitric and sulfuric acids, commonly known as acid rain, which damages forests and acidifies soil and waterways. Harvard School of Public Health studies have shown that SO2 emissions from power plants significantly harm the cardiovascular and respiratory health of people who live near the plants. According to EPA studies, fine particle pollution from power plants results in thousands of premature deaths each year Nitrogen oxide is tied to ground-level ozone, which is especially harmful to children and people with respiratory problems such as asthma. Ground-level ozone is formed when NOx and volatile organic compounds (VOCs) react in sunlight. NOx also reacts with ammonia, moisture, and other compounds to form fine particle pollution, which damages lung tissue and is linked to premature death. Small particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease such as emphysema and bronchitis, and aggravate heart disease.
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The hydrogenation conditions are normally such that over 95% of the nitric acid is converted in the first stage of a process. This requires the temperature, pressure, feed rate, and quantity catalyst be optimized or adjusted to achieve this conversion. Optionally, a second stage could be used for higher conversion. Continuous feed of the aqueous solution to the suspended catalyst slurry, with simultaneous removal of the product solution through a 1-10 micron filter, is especially advantageous. High conversions, (> 90%) of the nitric acid to ammonia, with only minor losses of catalyst, can be achieved at steady state in this manner.
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Nitric acid is formed in a two-step procedure. First, a mixture of air and ammonia gas is oxidized in two steps into nitric oxide. When the nitric oxide dissolves in water in the presence of oxygen, the nitric acid is formed.
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Ammonia