Uses of ammonia

The main uses for ammonia are directly as fertilizer or for conversion to ammonium nitrate, ammonium sulphate, nitric acid or urea which forms a highly nitrogenous fertilizer. A list of its other main uses is given in Table 3.8. 

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Uses of ammonia and ammonium compounds. Most of the ammonia produced is used in the manufaeture of nitrogenous fertilisers such as ammonium sulphate. Other uses include nitric acid and synthetic fibre and plastic manufacture. 

Markets. Industrial use of ammonia varies according to region. Eor example, industrial usage represents 20% of the ammonia production in the United States and Western Europe, 10% in the USSR, 1—10% in Asia, and 5% in Latin America and North Africa (79). Fertiliser ammonia consumed domestically in most countries is converted to straight or compound fertilisers such as urea, ammonium nitrate, diammonium phosphate, and various grades of mixed fertilisers. However, almost 29% of ammonia nitrogen in the United States is consumed as direct appHcation material. The use of nitrogen solution such as urea and ammonium nitrate (UAN) has also become popular in the United States and the USSR. 

As CFG refrigerants are phased out of production, their replacements in the cold storage appHcations will be HFC candidates such as R-134a, R-404A, and R-507. The use of ammonia, which is considered an environmentally benign refrigerant, will continue to play an ever-increasing role. 

In the future, CFCs and HCFCs will play a smaller role as they are phased out and replaced by HFCs such as R-134a, R-125, and R-507 where ammonia or hydrocarbons may not be considered appropriate. Because many industrial appHcations can safely manage the safety issues with ammonia, it is expected that the use of ammonia in this sector will continue to grow and may displace up to one-third of the industrial CFC and HCFC market of the late 1990s. 

The cleavage products of several sulfonates are utilized on an industrial scale (Fig. 3). The fusion of aromatic sulfonates with sodium hydroxide [1310-73-2J and other caustic alkalies produces phenohc salts (see Alkylphenols Phenol). Chlorinated aromatics are produced by treatment of an aromatic sulfonate with hydrochloric acid and sodium chlorate [7775-09-9J. Nitriles (qv) (see Supplement) can be produced by reaction of a sulfonate with a cyanide salt. Arenesulfonates can be converted to amines with the use of ammonia. This transformation is also rather facile using mono- and dialkylamines. 

The most important use of ammonia is in the production of nitric acid (HNO3). Ammonia burns in oxygen, releasing hydrogen to form water and free nitrogen. With the catalysts platinum and rhodium, ammonia is oxidized and reacted with water to form nitric acid. Nitric acid treated... 

The major end use of ammonia is the fertilizer field for the production of urea, ammonium nitrate and ammonium phosphate, and sulfate. Anhydrous ammonia could be directly applied to the soil as a fertilizer. Urea is gaining wide acceptance as a slow-acting fertilizer. 

The safety aspects of ammonia plants are well documented and there is reason to expect an increase in the use of ammonia as a refrigerant. 

In certain direct steam-contact process applications (such as in food and beverage processing or pharmaceutical preparations) the use of amine-based products in steam and condensate systems is subject to legal restrictions. Also, the use of ammonia or amines may be dependent on the materials of construction employed or technical limitations (such as the risk of copper alloy corrosion). 

An example of the use of ammonia is the deposition of silicon nitride, a common reaction in the semiconductor industry ]... 

The use of ammonia for the protonation of nitroarenes leads frequently to formation of aduct ions, e.g. [M + NH4]+, but not to the protonated species (MH+)112,113. The ammonia chemical ionization spectrum of nitrobenzene shows, in addition to a series of adduct ions, a dominant signal corresponding to the anilinium ion (m/z 94)112114115. Evidence for the isomerization of the [M + NR ]"1" adduct followed by successive loss of NO and OH or NH3 to give ions corresponding to the substitution products, e.g. the anilinium ion, has been given115 see Scheme 41. 

Toxic substances such as chlorine and ammonia are a homeland security concern in part because of their widespread use in industrial applications and, hence, their accessibility. When released into the air or water in high concentrations, they can be very poisonous. The major use of ammonia and its compounds is as fertilizers. 

A second case of the use of ammonia for odour measurement is reported by van Harreveld (3). 

A diverse group of secondary and tertiary amines are readily synthesized from the reaction of primary and secondary amines with allylic carbonates in the presence of preformed iridium metalacycles, but the direct synthesis of primary amines via iridium-catalyzed allylic amination requires the use of ammonia as a nucleophile. The asymmetric allylation of ammonia had not been reported until very recently, and it is not a common reagent in other metal-catalyzed reactions. Nonetheless, Hartwig and coworkers developed the reactions of ammonia with allylic carbonates in the presence of la generated in situ [89]. Reactions conducted in the initial work led exclusively to the products from diallylation (Scheme 16). Further advances in... 

The direct use of ammonia or dinitrogen and hydrogen to synthesize imido amido complexes is essentially pioneers territory [58, 59]. Recently, we have formed, by surface organometaUic chemistry, a well-defined Ta amido imido species by reaction with either ammonia [9] or with dinitrogen and dihydrogen at subatmospheric pressure [60]. 

The single largest use of ammonia is its direct apphcation as fertdizer, and in the manufacture of ammonium fertilizers that have increased world food production dramatically. Such ammonia-based fertilizers are now the primary source of nitrogen in farm soils. Ammonia also is used in the manufacture of nitric acid, synthetic fibers, plastics, explosives and miscellaneous ammonium salts. Liquid ammonia is used as a solvent for many inorganic reactions in non-aqueous phase. Other apphcations include synthesis of amines and imines as a fluid for supercritical fluid extraction and chromatography and as a reference standard in i N-NMR. 

When the lithium dianion was prepared in a completely different manner, viz from an a,j -epoxy ester 8 by treatment of the latter with lithium in liquid ammonia and tetrahydrofuran at - 78 C, alkylation experiments (CH3I, — 40 °C) gave the expected a-alkyl- -hydroxy ester 10, but in a ratio of only 4 1 in favor of the anti-isomer and not in the usual 19 1 ratio15. This result could be interpreted as a direct consequence of the participation of an intermolecularly chelated dianionic enolate such as 7 which gains importance because of the use of ammonia as a cosolvent. 

As mentioned earlier, the synthesis of primary amides is rather challenging due to technical difficulty in handling gaseous ammonia. Thus, the use of ammonia substitutes such as HMDS and formamide has been studied (see Schemes 21 and 22). With the use of microwave irradiation, however, it has been shown that it is possible to generate both CO and ammonia at the same time for the synthesis of primary amides from aryl bromides. This protocol is very useful for laboratory organic syntheses, especially combinatorial syntheses. As Scheme 29 illustrates, the Pd-catalyzed aminocarbonylation of aryl bromides 200 with formamide (33.5 equiv.) in the presence of KOBu (1.5 equiv.) and imidazole (1 equiv.) with microwave irradiation for 400 s (6.7 min) gave the corresponding benzamides... 

ZnO films for use as buffer layers in photovoltaic cells (see Chap. 9) have been chemically deposited from aqueous solutions of ZnS04 and ammonia [57]. The solution was heated to 65°C, and adherent, compact Zn(OH)2 + ZnO films were formed after one hour. Low-temperature annealing converted the hydroxide to oxide. The solution composition will be important in this deposition. On one hand, increased ammonia concentration will increase the pH and therefore the homogeneous Zn(OH)2 precipitation in solution. However, further increase in ammonia concentration will redissolve the hydroxide as the ammine complex. There will clearly be an optimum ammonia (and zinc) concentration where Zn(OH)2 does form, but slowly enough to prevent massive homogeneous precipitation. The use of ammonia in (hydr)oxide deposition derives, in part at least, from its gradual loss by evaporation if the system is not closed [58], Any open solution of an ammonia-complexed metal ion (which forms an insoluble hydroxide or hydrated oxide) should eventually precipitate the (hydr)oxide for this reason alone. 

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