Fixation of Atmospheric Nitrogen

In 1895 Frank and Caro discovered a process to fix atmospheric nitrogen using barium or calcium carbide at high temperatures, as follows  

It was recognized that the calcium cyanamide thus formed could be used directly as a fertilizer. Caro obtained a patent in 1900 for the generation of ammonia from the cyanamide by hydrolysis. 

Although the formation of calcium carbide from calcium oxide and carbon requires temperatures as high as 2300 K, the overall power necessary for this fixation process was only one quarter of that required by the arc process. The reasons for the observation are described below. 

The thermodynamic equilibrium concentration of nitric oxide is very low at normal temperatures, and in order to obtain an appreciable amount of nitric oxide it is necessary to heat up the air to temperatures above 3000 K. This was only possible at that time by the use of an electric arc and, even then, a very large quantity of electric energy was necessary. 

The concentration of nitric oxide in the effluent gas produced by this process was only 2%. The energy consumption was enormous and, consequently, the process could only be viable in countries where cheap electric power was available. This is the reason why the first plant was operated in Notodden, Norway, in 1904, using hydroelectricity. 

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Other PK variations include microwave conditions, solid-phase synthesis, and the fixation of atmospheric nitrogen as the nitrogen source (27—>28). Hexamethyldisilazane (HMDS) is also an excellent ammonia equivalent in the PK synthesis. For example, 2,5-hexanedione and HMDS on alumina gives 2,5-dimethylpyrrole in 81% yield at room temperature. Ammonium formate can be used as a nitrogen source in the PK synthesis of pyrroles from l,4-diaryl-2-butene-l,4-diones under Pd-catalyzed transfer hydrogenation conditions. 

There are well over 100 gaseous and aqueous phase reactions that can lead to acid formation and more than fifty oxidizing agents and catalysts may be involved. However, in the simplest terms sulfur in fuels is oxidized to SO2, and SO2 in the atmosphere is further oxidized and hydrolyzed to sulfuric acid. Most nitric acid is formed by the fixation of atmospheric nitrogen gas (N2) to NO. (NO and NO2) during high temperature combustion, followed by further oxidation and hydrolysis that produces nitric acid in the atmosphere. These materials can be dry-... 

H.W. Webb, Absorption of Nitrous Gases , Longmans, Green Co, London (1923) (Absorption of gases by nitric acid description of various absorption towers, etc) 16) F.A. Ernst, Fixation of Atmospheric Nitrogen , Van Nostrand, NY (1928) 17) Anon, IEC 22, 433 (1930)... 

Fixed beds are the main interest of this Section. Usually it is adequate to assume that the fluid and solid are at the same temperature at a point. There are cyclic processes, however, where the solid is first heated with flue gases or by burning off carbon before contacting the reacting fluid for a time. A moving bed of heated pebbles (Phillips pebble heater) has been used for the production of olefins from butane and for the fixation of atmospheric nitrogen. A fluidized sand cracker for the production of olefins functions similaiiy, with burning in a separate zone. 

CaCa is used extensively for the manuf of acetylene, and Ca cyanamide(by fixation of atmospheric nitrogen), as the starting material for making the melamine family of resins, for the manuf of acetylene black and many other purposes Refs l)Beil 1,242,(105), [218] [ 12i 2)F. Wohler, Ann 124, 220( 1862) 3)H. 

There are a large number of chain reactions that are significant in industrial processes or play an important role for the environment. Classes of chain reactions that are relevant industrially include hydrogen/halogen reactions and pyrolysis of hydrocarbons, which are both discussed below, and free-radical polymerization discussed in many textbooks on kinetics. As an example of a chain reaction of significant environmental consequence, we will discuss formation of nitric oxide from fixation of atmospheric nitrogen. 

Figure 17.14. Some unusual reactor configurations, (a) Flame reactor for making ethylene and acetylene from liquid hydrocarbons [Patton et al., Pet Refin 37(li) 180, (1958)]. (b) Shallow bed reactor for oxidation of ammonia, using Pt-Rh gauze [Gillespie and Kenson, Chemtech, 625 (Oct. 1971)]. (c) Sdioenherr furnace for fixation of atmospheric nitrogen, (d) Production of acetic acid anhydride from acetic acid and gaseous ketene in a mixing pump, (e) Phillips reactor for low pressure polymerization of ethylene (closed loop tubular reactor), (f) Polymerization of ethylene at high pressure.

Nitrate. Sodium nitrate, nitrate of soda, Chile saltpeter, caliche, [CAS 7631-99-4], NaN03, white solid, soluble, mp 308°C. source in nature is Chile, in the fixation of atmospheric nitrogen HN03 is frequently transformed by sodium carbonate into sodium nitrate, and the solution evaporated. Used tl) as an important nitrogenous fertilizer, (2) as a source of nitrate and HNO3, (3) in pyrotechnics, (4) in fluxes,... 

Cottrell, Frederick G. (1877-1948). American scientist, inventor of an electrostatic precipitator, now known as Cottrell Precipitator, for smoke, dust fumes. Among other inventions are the pebble bed furnace, boiling point apparatus the Cottrell-Daniels process for fixation of atmospheric nitrogen. Cottrell was Director of US Bureau of Mines Director of the Fixed Nitrogen Research Laboratory, and founder of the Research Corporation, a nonprofit organization... 

A special place among kinetic studies in combustion is occupied by work on nitrogen oxidation. Begun at the AS USSR Institute of Chemical Physics in the mid-thirties on the initiative of N. N. Semenov, research to determine the feasibility of fixation of atmospheric nitrogen for the production of mineral fertilizers has today found application in the development of environmental protection measures for toxic components of combustion products, including nitrogen oxide. In December, 1939, Ya.B. defended his doctoral dissertation on The Oxidation of Nitrogen in Combustion and Explosions. It was precisely these studies, in which D. A. Frank-Kamenetskii, P. Ya. Sadovnikov, A. A. Rudoy, A. A. Kovalskii, and others actively participated, that led Ya.B. to the problems of combustion and detonation. 

Hendrikson WG, Daniels F. Fixation of atmospheric nitrogen in a gas-heated furnace. Ind. Eng. Chem 1953 45 26113-2615. 

Another process for the fixation of atmospheric nitrogen is the subject of an English Patent, 1894, 18315. 

Vanadium (II)/catechol systems can be useful in fixation of atmospheric nitrogen, reducing it to ammonia [244-246]. A detailed EPR study concluded that the active catalyst is a trinuclear V-Cat species 966 [125a,246,247] ... 

Environmental quality parameters such as oxygen depletion, changes in primary productivity, and changes in the processing of nutrients such as mineralization of organic matter or fixation of atmospheric nitrogen... 

Dinitrogen makes up 79 mol per cent of dry air. The element is essential for life and is one of the elements often in short supply, as fixation of atmospheric nitrogen to form chemically usable compounds is a difficult process. 

One of the most important uses of hydrogen today is for the fixation of atmospheric nitrogen into the form of ammonia. 

One of the most important uses of hydrogen today is for the fixation of atmospheric nitrogen into the form of ammonia. Ammonia then carries, either directly or in combination with other compounds, such as urea, ammonium nitrate and various NPK materials, the supplemental nitrogen nutrient to the soil for plant growth. 

The direct fixation of atmospheric nitrogen and its conversion into ammonia, then urea, then melamine. 

The extraordinary demand for nitric acid and nitrates brought about by the abnormal conditions consequent on the great European War of 1914 and succeeding years gave a powerful impetus to the development of synthetic methods for the fixation of atmospheric nitrogen. For an account of these developments reference should be made to Volume VI. of this series. 

Probably the one high temperature chemical process which has received the most attention is the fixation of atmospheric nitrogen as nitric oxide. The advantage of high temperatures is apparent from Fig. 18,... 

Molybdenum is important in agriculture, and plays a vital part in the fixation of atmospheric nitrogen. However, the concentration present in the soil is critical in relation to copper metabolism. If the molybdenum intake by animals is too high, especially with ruminants, then a copper-deficiency problem called "molybdenosis" can occur. On the other hand, too low an intake of molybdenum can lead to excessive copper metabolism and copper poisoning. The total use of molybdenum... 

Whatever data we have generally available in most publications are mean concentrations of litter or leaves of all species in an area. For example, it is not all species which contribute to fixation of atmospheric nitrogen and contribute to a general improvement of soil fertility. Calcicole species can probably survive well only on soils with neutral or alkaline pH. The ecological significance of the differences in relative importance of functional groups such as Al-accumulators or Leguminosae in native communities is rarely discussed in the literature (Haridasan and Araujo 1988). 

The Fixation of Nitrogen as Nitric Oxide. A method (the arc process) formerly used for fixation of atmospheric nitrogen but now abandoned is the direct combination of nitrogen and oxygen to nitric oxide at the high temperature of the electric arc. The reaction... 

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