Atmospheric nitrogen fixation

Atmospheric monitoring, 23 139 Atmospheric nitrogen, biological fixation of, 11 111-112... 

A new method for nitrogen fixation involved the treatment of titanium tetraisopropoxide with lithium metal and trimethylsilyl chloride in the presence of a nitrogen atmosphere to give either a titanium-nitrogen complex and/or N(TMS)3 9 (proposed structures) <04BCJ1655>. This reagent was utilized to prepare pyrrole, indoles, and other nitrogen heterocycles. For example, treatment of preformed 9 with enol triflate 8 led to fused pyrrole 10. 

Reports on H2S emissions from common mineral soils are not very consistent and in part contradictory. For example, Bloomfield (1969) and Siman and Jansson (1976) detected the evolution of H2S from water-logged soils amended with sulfate and incubated under nitrogen atmosphere, whereas Banwart and Bremner (1976), who studied 25 soils from Iowa, failed to detect H2S under any conditions, even the most favorable ones. The latter authors ascribe the lack of H2S emission to sorption by the soils, possibly accompanied by fixation as FeS. The field measurements of Jaeschke et al. (1978, 1980) indicate that normally aerobic soils absorb H2S rather than emit it. Farwell et al. (1979), who studied agriclutural, forest, and marsh soils, also found only the last type to emit measurable quantities of H2S. Delmas et al. (1980), by contrast, found H2S to evolve from various soils in France, whose classification was not given but that cannot have differed much from those studied by Jaeschke et al. (1978). 

Fixation of atmospheric oxygen and nitrogen at high-flame temperature. 

Nitrogen fixation Conversion of atmospheric nitrogen into organic nitrogen compounds available to green plants a process that can be carried out only by certain strains of soil bacteria. 

Figure 11.2 Distribution of nitrogen in the biosphere and annual transfer rates can be estimated only within broad limits. The two quantities known with high confidence are the amount of niirogcn in the atmosphere and the rate of industrial fixation. The inventories (within the boxes) are expressed in terms of 10 tonnes of N the transfers (indicated by arrows) are in 10 tonnes of N. Taken from ref. 7 with some adjustments for more recent data.

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)... 

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