The Ostwald process is chemical process for producing nitric acid, which was developed by Wilhelm Ostwald (patented 1902). It is a mainstay of the modern chemical industry. Historically and practically it is closely associated with the Haber process, which provides the requisite raw material, ammonia. Chemistry (derived from the Arabic word kimia, alchemy, where al is Arabic for the) is the science that deals with the properties of organic and inorganic substances and their interactions with other organic and inorganic substances. ... Look up Process in Wiktionary, the free dictionary Process (lat. ... R-phrases , S-phrases , , , , Flash point not applicable RTECS number QU5775000 Supplementary data page Structure and properties n, εr, etc. ... Wilhelm Ostwald Friedrich Wilhelm Ostwald (commonly just Wilhelm Ostwald) (September 2, 1853 - April 4, 1932) was a German chemist. ... Chemical tanks in Lillebonne, France Chemical industry includes those industries involved in the production of petrochemicals, agrochemicals, pharmaceuticals, polymers, paints, oleochemicals etc. ... The Haber Process (also Haber-Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... Ammonia is a compound of nitrogen and hydrogen with the formula NH3. ...

Description

Ammonia is converted to nitric acid in two stages. It is oxidized (in a sense "burned") by heating with oxygen in the presence of a catalyst of platinum with 10% rhodium, to form nitric oxide and water. This step is strongly exothermic, making it a useful heat source once initiated (ΔH = -950 kJ): The most fundamental reactions in chemistry are the redox processes. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... A catalyst (Greek: καταλύτης, catalytÄ“s) is a substance that accelerates the rate (speed) of a chemical reaction (see also catalysis). ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... Rh redirects here. ... The chemical compound nitric oxide is a gas with chemical formula NO. It is an important signaling molecule in the body of mammals including humans, one of the few gaseous signaling molecules known. ... Water (from the Old English word wæter; c. ...

4 NH_3(g) + 5 O_2(g) → 4 NO_(g) + 6 H₂O_(g)

Stage two (combining two reaction steps) is carried out in the presence of water in an absorption apparatus. Initially nitric oxide is oxidized again to yield nitrogen dioxide: Absorption has a number of meanings: In physics, absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... The chemical compound nitrogen dioxide (NO2) is a red or orange/brown gas with a characteristic sharp, biting odor. ...

2 NO_(g) + O_2(g) → 2 NO_2(g)

This gas is then readily absorbed by the water, yielding the desired product (nitric acid, albeit in a dilute form), while reducing a portion of it back to nitric oxide: Redox reactions include all chemical processes in which atoms have their oxidation number (oxidation state) changed. ...

3 NO_2(g) + H₂O_(l) → 2 HNO_3(aq) + NO_(g)

The NO is recycled, and the acid is concentrated to the required strength by distillation. Strathisla whisky distillery in Keith, Scotland Distillation is a means of separating liquids through differences in their vapor pressures. ...

Typical conditions for the first stage, which contribute to an overall yield of about 96%, are: Yield in chemistry, also known as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction. ...

• pressure between 4 and 10 atmospheres (approx. 400-1010 kPa or 60-145 psig) and
• temperatures between 975 and 1125 K (approx. 700-850°C. or 1295-1565°F.).

Pressure (symbol: p) is the force per unit area acting on a surface in a direction perpendicular to that surface. ... When expressed as a measurement, an atmosphere (symbol: atm) or standard atmosphere is a unit of pressure roughly equal to the average atmospheric pressure at sea level on Earth. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ...

History

An earlier patent (Kuhlmann, 1838) described the basic chemistry, but ammonia (from animal sources) was scarce at the time, so it was probably of only academic interest, either then or when Ostwald patented his version in 1902. A later date is frequently given for the development of the process (1908), and it may be that by then Fritz Haber's method of making ammonia was known, which would have changed the outlook entirely. Ostwald's primary contributions seem to have been practical ones concerning the catalyst and operating conditions, a matter perhaps more of chemical engineering than of basic science. Fritz Haber in 1918. ... The Haber Process (also Haber-Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... Chemical engineering is the application of science, in particular chemistry, physics and mathematics, to the process of converting raw materials or chemicals into more useful or valuable forms. ... Wikimedia Commons has media related to: Science For the scientific journal named Science, see Science (journal). ...

Prior to this the source of most industrial nitrogen was nitrates, primarily imported Chilean saltpeter, from which nitric acid was produced by treatment with sulfuric acid. The Ostwald process gained prominence as an adjunct to the fixing of nitrogen (Haber Process). The combined processes undoubtedly prolonged World War I, when Germany's overseas sources were cut off and explosives production was threatened. Subsequently their use of widely available raw materials (and the resulting low cost) led to their general adoption, resulting in vastly increased nitrogen consumption, mostly as fertilizers. Sodium nitrate is a type of salt(NaNO3)which has long been used as an ingredient in explosives and in solid rocket propellants, as well as in glass and pottery enamel, and as a food preservative (such as in hot dogs), and has been mined extensively for those purposes. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... Combatants Entente Powers Central Powers Commanders {{{commander1}}} {{{commander2}}} Strength {{{strength1}}} {{{strength2}}} Casualties > 5 million military deaths > 3 million military deaths {{{notes}}} World War I, also known as the First World War and (before 1939) the Great War, the War of the Nations, War to End All Wars was a world... This article is concerned solely with chemical explosives. ... Fertilisers or fertilizers are compounds given to plants with the intention of promoting growth; they are usually applied either via the soil, for uptake by plant roots, or by foliar spraying, for uptake through leaves. ...

Initially the process was carried out in low pressure stoneware vessels, but the introduction of stainless steel made higher pressures practical, leading to higher yields. Stoneware is an impervious type of pottery distinguished primarily by its firing temperature (from about 1200°C to 1315°C). ... In metallurgy, stainless steel (inox) is defined as a ferrous alloy with a minimum of 10. ...

External links

• Physics Daily -- but formula for last step seems to be in error
• Nitrogen & Phosphorus (General Chemistry course), Purdue University
• Drake, G; "Processes for the Manufacture of Nitric Acid" (1963), International Fertiliser Society
• Manufacturing Nitrates: the Ostwald process Carlton Comprehensive High School; Prince Albert; Saskatchewan, Canada.