Ammonia and Its Compounds

Ammonia, NH3, is an easily condensable gas (b.p.—33.4°C m.p.—77.7 C). readily soluble in water. The gas is colorless and has a pungent odor, often detected around stables and manure piles, where ammonia is produced by decomposition of organic matter. The solution of ammonia in water, called ammonium hydroxide solution (or sometimes aqua ammonia), contains the molecular species NH3, NH4OH (ammonium hydroxide), NH4 , and OH . Ammonium hydroxide is a weak base, and is only slightly ionized to ammonium ion, NH4 , and hydroxide ion OH  

NH4+ ion can be described as having four electrons in four tetrahedral sp orbitals. In the ammonium hydroxide molecule the ammonium ion and the hydroxide ion are held together by a hydrogen bond (Section 9-6). 

Ammonia is easily made in the laboratory by heating an ammonium salt, such as ammonium chloride, NH4CI, with a strong alkali, such as sodium hydroxide or calcium hydroxide  

The gas may also be made by warming concentrated ammonium hydroxide. 

Smaller amounts of ammonia are obtained as a by-product in the manufacture of coke and illuminating gas by the distillation of coal, and are made by the cyanamide process. In the cyanamide process a mixture of lime and coke is heated in an electric furnace, forming calcium acetylide (calcium carbide), CaC2  

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Nitrogen compounds These also arise from both natural and synthetic sources. Thus ammonia is formed in the atmosphere during electrical storms, but increases in the ammonium ion concentration in rainfall over Europe in recent years are attributed to increased use of artiflcial fertilisers. Ammonium compounds in solution may increase the wettability of a metaland the action of ammonia and its compounds in causing season cracking , a type of stress-corrosion cracking of cold-worked brass, is well documented. 

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. 

In the 1870s, the French biologists Jean Schloesing and Achille Muntz discovered that nitrification is a biological process (Schloesing and Muntz 1877). Although years before (1859), Louis Pasteur had theorized that the process was biological, he was never able to prove it. The phenomenon of nitrification, i. e., the formation of nitrites and nitrates from ammonia and its compounds in the soil, was formerly held to be a purely chemical process. 

A flow diagram for the system is shown in Figure 5. Feed gas is dried, and ammonia and sulfur compounds are removed to prevent the irreversible buildup of insoluble salts in the system. Water and soHds formed by trace ammonia and sulfur compounds are removed in the solvent maintenance section (96). The pretreated carbon monoxide feed gas enters the absorber where it is selectively absorbed by a countercurrent flow of solvent to form a carbon monoxide complex with the active copper salt. The carbon monoxide-rich solution flows from the bottom of the absorber to a flash vessel where physically absorbed gas species such as hydrogen, nitrogen, and methane are removed. The solution is then sent to the stripper where the carbon monoxide is released from the complex by heating and pressure reduction to about 0.15 MPa (1.5 atm). The solvent is stripped of residual carbon monoxide, heat-exchanged with the stripper feed, and pumped to the top of the absorber to complete the cycle. 

Part 1 Ammonia. Part 2 l-Chloro-2,3-epoxypropane (epichlorohydrmj. Part 3 Carcinogenicity of cadmium and its compounds... 

As expected, compounds of type 78 possess an acidic hydrogen and readily form A-acetyl derivatives. The acetyl group is removed by warming with aqueous ammonia, and it is replaced by a methyl group when the compound is treated with alkaline dimethyl sulfate or excess diazomethane. 

Ammonia and its inorganic and organic derivatives (HNR R2) couple readily with arenediazonium ions to give triazenes (Ar — N2—NR R2). Originally these compounds were called diazoamino compounds. Nowadays IUPAC nomenclature (IUPAC, 1979, Rule 942.2) recommends that the prefix diazoamino should be used only for compounds with the same organic residue at each end of the — N2 —NH — group. 

Addition of ammonia and its derivatives to carbonyl compounds preparation of oximes and imine derivatives (Schiff s bases)... 

Ammonia Ammonia and its synthesis by the Haber process serve as the gateway to nitrogen chemistry because ammonia is the starting material for the industrial synthesis of other important nitrogen compounds, such as nitric acid. Used in agriculture as a fertilizer, ammonia is the most commercially important compound of nitrogen. 

Ammonia and its derivatives are very prone to react in this way thus conjugate addition provides a method for the preparation of j8-amino carbonyl compounds. 

Ammonium chloride exerts a catalytic, accelerating effect on certain reactions, examples being the interaction of iodic acid and sulphurous acid,17 and the inversion of sucrose by hydrochloric acid.18 It is employed in the manufacture of ammonia and ammonium compounds, in pharmacy and the dye-industry, and in soldering. 

Ammonia possesses similar physical properties to that of water, which is similarly highly associated. It is a good solvent for many compounds. Owing to the lower dielectric constant (NH3 16.9, H2O 78.3 at 298 K) of ammonia in comparison with water, less polar compounds are more soluble in ammonia and polar compounds, for example, salts, are more soluble in water. Organic compounds tend to have a higher solubihty in ammonia than in water. Armnonium salts, nitrates, nitrites, cyanides, and thiocyanates dissolve readily in ammonia. The solubihty increases from fluorides to chlorides, bromides, and iodides. Salts with higher charged ions dissolve only poorly in ammonia. This results in the reversal of some precipitation reactions in ammonia compared to water. 

SAFETY PROFILE Poison by intravenous route. See also FLUORIDES, AMMONIA, and TITANIUM COMPOUNDS. When heated to decomposition it emits very toxic fumes of F and NOx. 

The fate of the iminal depends upon the reaction conditions. It may cleave in the manner observed by Emmons to yield ammonia and dicarbonyl compounds that aldolize under the alkaline reaction conditions, or it may undergo an S y2 -like substitution to produce the isomeric iminal ether 53. When the a-hydrogen and oxaziridine ring are constrained to a cis relationship, no reaction occurs under these conditions. This mechanism has received further study and has been generally confirmed. ... 

The most common compounds of nitrogen are those in which the element demonstrates oxidation numbers of 3, 3+, or 5+. Ammonia (NH3) and its compounds (ammonium compounds) are examples of the first of these, the nitrites (NO2 ) are examples of the 3+ oxidatiou state, and the nitrates (N03 ) are examples of the 5+ oxidation state. 

B. Reaction of Diazonium Compounds with Nucleophiles I. Ammonia and its derivatives... 

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