Ammonia and ammonium salts

In the laboratory NH3 is usually obtained from cylinders unless isotopically enriched species such as NH3 or NDj are required. Pure dry can be prepared by treating an enriched NH salt with an excess of KOH and drying the product gas over metallic Na. Reduction of NOs or with Devarda s alloy (50% 

45% Al, 5% Zn) in alkaline solution provides an alternative route as docs the hydrolysis of a nitride, c.g.  

CzuppoN, S. A. Knez and J.. M. Rovner, Ammo-ria, Kirk-Othrrier Encyclopedia of Chemical Technology 4lh edn.. Vol. 2, pp. 638-91, Wiley, New York. 1992 

The operation of a large synthetic ammonia plant based on natural gas involves a delicately balanced sequence of reactions. The gas is first desulfurized to remove compounds which will poison the metal catalysts, then compressed to 30 atm and reacted with steam over a nickel catalyst at 750°C in the primary steam reformer to produce H2 and oxides of carbon  

Under these conditions the issuing gases contain some 9% of unreacted methane sufficient air is injected via a compressor to give a final composition of 1 3 N2 H2 and the air bums in the hydrogen thereby heating the gas to 1100°C in the secondary reformer  

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The baking process, particularly the batch variety, presents a number of serious disadvantages. Not only does the reaction produce solid urea decomposition products, but it also releases large amounts of ammonia and ammonium salts which escape by sublimation. The foam which is thus formed makes for a porous reaction mixture, which in turn even prevents heat conduction. Moreover, the reaction mixture tends to adhere to the surface of the reaction vessel and the stirring unit a phenomenon which adds to the complexity of the problem. 

Although S-diketones cannot compete with hydroxyoximes for the extraction of copper from acid media, they do have advantages for extraction from ammoniacal leach solutions because, unlike hydroxyoximes, they do not transfer ammonia. The extraction follows Eq. (11.6), and the extent of extraction depends on the concentration of ammonia and ammonium salts. 

The chromi-ammines are produced by the action of ammonia and ammonium salts on chromic salts, or by the action of ammonia in presence of ammonium salts on chromous salts and subsequent oxidation. The second method is analogous to that for the formation of cobalt-ammines. The chromi-ammines form a group of coloured substances, and comprise unstable and stable derivatives, some of which are very complex. 

Agriculture therefore depends on there being a sufficient supply of inorganic nutrients to plants. Cereals, vegetables, fruit-bearing trees or plants, and animal fodder require bioavailable nutrients, that is, nutrients in forms that they can use. Since intensive agriculture depletes many natural nutrients, synthetic nutrients (fertilizers) must be supplied.1-7 In particular, we need to fix the inert N2 of the atmosphere as soluble, reactive compounds such as nitrates, ammonia, and ammonium salts. Other major fertilizer components are sulfate, potassium, and phosphate ions. It may also be necessary to provide trace nutrients, such as cobalt compounds, or to remove excess soil acidity by treatment with lime (CaO). World fertilizer demand in the year 2001 is expected to be about 1.5 x 10s metric tons N, 7.6 x 107 metric tons P2O5, and 6.7 x 107 metric tons K2O these projections represent an... 

Uses.—Ammonium chloride is used in pharmacy in certain galvanic batteries and in the preparation of ammonia and ammonium salts. It is used in the manufacture of colours in cotton printing in tin plating in galvanizing and in soldering. 

The thiocyanates are generally soluble in water, the exceptions being those of lead, silver, mercury and copper. Most of them dissolve also in alcohol and ether. Aqueous solutions of the alkali thiocyanates undergo atmospheric oxidation under the influence of sunlight with solutions of medium concentration this change takes place rapidly, with separation of a yellow, amorphous precipitate consisting of pseudocyanogen sulphide, (CNS)3 (cf. p. 236). The concentration of thiocyanate most favourable to the separation of this sulphide is about 50 per cent, in summer and 10 per cent, in winter. In addition to this substance the products of the photochemical oxidation of potassium thiocyanate include hydrocyanic acid, sulphate, carbon dioxide, ammonia and ammonium salts ... 

The reaction of furans with ammonia and its derivatives is of considerable synthetic utility (B-73MI31 too). Substituted furan-2-carbaldehydes and 2-acylfurans on heating with ammonia and ammonium salts, often under pressure, yield 3-hydroxypyridines. The mechanism of this reaction is thought to involve nucleophilic attack of ammonia at the 2-position. Ring opening affords an amino aldehyde or ketone and thence, by reclosure, the 3-hydroxy-pyridine (Scheme 29). A wide range of substitutents is tolerated. Primary amines with furan-2-carbaldehydes yield A-substituted pyrroles, the closure of the intermediate... 

By decomposition with steam it is used for preparing ammonia and ammonium salts. 

This reaction takes place in a matter of seconds and produces significantly more fluorescence than the diacetylmonoxime fluorophors. Excess reagent is quickly hydrolyzed to form nonfluorescent water soluble products. Secondary, tertiary, and aromatic amines did not react with fluram to produce any measureable fluorescence. The reaction did not occur when ammonia and ammonium salts were tested for fluorescence. Mass spectrometry of an actual field sample confirmed that the substitution product is the fluorescent species that is shown above. Further mass spectra studies indicated that dimethyl-urea is not produced during this reaction. This was later confirmed by introducing known quantities of the urea and little or no fluorescence was noted. These tests indicate that Fluram does react with the primary amine intermediate on the adsorbent according to the above equation, and that monomethyl amine and other primary aliphatic amines would interfere. 

VI.16 IDENTIFICATION OF GROUP V CATIONS ON THE SEMIMICRO SCALE Apart from a partial separation of magnesium, it is not possible to separate the Group V cations from one another it is however simple to carry out individual tests for each of them. As we have used ammonia and ammonium salts in the previous separations, we cannot test for ammonium ions in the... 

The normal carbonate is a decomposition-product of urine,11 and plays an important part in the nitrification of ammonia and ammonium salts in the soil.12... 

Ammonia.—The liquid portion, held by the condenser, consists of the ammoniacal liquor (water solution of ammonia and some other compounds) and coal tar, and is easily separated into the two constituents. The ammoniacal liquor together with the wash water from the purification of the gas is known as gas liquor and forms the large commercial source of ammonia and ammonium salts. 

Incompatible with halides anionic emulsifying agents and suspending agents tragacanth starch talc sodium metabisulfite sodium thiosulfate disodium edetate silicates aluminum and other metals amino acids ammonia and ammonium salts sulfur compounds rubber and some plastics. 

Phenylmercuric salts are incompatible with halides, particularly bromides and iodides, as they form less-soluble halogen compounds. At concentrations of 0.002% w/v precipitation may not occur in the presence of chlorides. Phenylmercuric salts are also incompatible with aluminum and other metals, ammonia and ammonium salts, amino acids, and with some sulfur compounds, e.g., in rubber. 

Ammonia and Ammonium Salts.—Ammonia, NHg, is a decomposition product of organic matter, resulting either from its destructive distillation or from its putrefaction and decay. 

The following may be considered as the chief sources of ammonia and ammonium salts, as they at present exist ... 

The Knoevenagel reaction is one of the oldest C-C bond forming reactions (see also Section 7.1) [36]. It involves the condensation of a carbonyl component (typically benzaldehyde) with a C-acid (typically ethyl cyanoacetate)-Figure 5. This classical reaction is usually catalyzed by organic bases (primary, secondary, and tertiary amines), ammonia, and ammonium salts [37]. 

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