Displacement, ammonia

Ethylamine, monoethylamine, CH3CH2NH2-B.p. 19 C. Prepared by reduction of acetonitrile or by heating ethyl chloride with alcoholic ammonia under pressure. It is a strong base and will displace ammonia from ammonium salts. Forms a crystalline hydrochloride and also crystalline compounds with various metallic chlorides. 

The hydroxide is strongly basic. It reacts with acids undergoing neutralization reactions i.e., reaction with HCl or HNO3 yields hydrated salt of lanthanum chloride or nitrate on evaporation and crystalhzation of the solution. It reacts with ammonium salts displacing ammonia ... 

The hydroxide, [Ir(NH3)6](OH)3, is obtained in solution by treating the chloride with moist silver oxide. The solution is strongly alkaline, displaces ammonia from ammonium salts, and precipitates the hydroxides of some metallic salts. If exposed to air containing carbon dioxide it quickly absorbs the gas, being transformed into the carbonate, [Ir(NH3)6]2(C03)3, which crystallises in microscopic plates. 

Tetrammino-platinous Hydroxide, [Pt(NH3)4](OH)2, the base of the series, is isolated by treating a solution of tlie sulphate with baryta. The liquid is filtered and evaporated in vacuo, when the hydroxide separates in white deliquescent needles. It is a strong base, absorbs carbon dioxide from the air, displaces ammonia from its salts, and precipitates metallic hydroxides from solution of their salts. It decomposes at 110° C., and ammonia is not liberated from it by potassium hydroxide. 

World demand for nitric acid will continue to be largely dependent upon demand for solid ammonium nitrate fertilizer and nitrogen fertilizer solutions that incorporate ammonium nitrate. Since the early 1980 s, urea has been displacing ammonia nitrate as a fertilizer. The resulting reduction in demand for nitric acid has been partially offset by the increased use of ammonium nitrate in explosives and by the growth in production of polyurethane foams and nylon-6,6. World nitric acid production declined by about 5% between 1987 and 1999, but it is projected to increase marginally by 2005. The declines occurred mainly in the former Soviet Union, Eastern Europe and Western Europe. Production increases occurred mainly in the United States and Africa91,104. Nitric Acid production in the United States is listed in Table 9.11. 

According to Moissan,4 ferrous oxide can exist in two polymorphic modifications, according as it is produced at high or at lower temperatures. The variety obtained at the lower temperatures, namely below 600° C., is more chemically reactive, uniting with oxygen, upon exposure to air, with such rapidity that the whole mass becomes incandescent. It decomposes water, slowly in the cold but with considerable rapidity at the boiling-point. It is readily soluble even in dilute acids, such as acetic acid, and easily displaces ammonia from its salts. 

Leucine aminopeptidase is interesting in that its active site contains two zinc atoms which together bind and activate the water molecule [74]. Despite this enzyme containing a dinuclear metal center at its active site, its mechanism, and specifically its mode of proton transfers reactions, appear to follow the general theme established by thermolysin and carboxypeptidase Adenosine deaminase and other members of the family of nucleoside and nucleotide deaminases utilize zinc-bound water as the catalytic nucleophile to displace ammonia from the 6-position of purines or the 4-position of pyrimidines and in all cases display inverse solvent deuterium isotope effects ranging from 0.3 to 0.8 on fec/Kni [75-80]. These effects are reminiscent of those observed for metallopro-teases and have their origins, like those of the proteases, in fractionation factors for the protons of the bound water that are less than one. 

Hydroxide, La(OII white, amorphous predp, prepd by adding excess of caustic alkali to a lanthanum salt soln. Strongly basic, displaces ammonia from ammonium salts, absorbs CO, from air- On dehydration yields La,0,.Hz0. 

Oxide, OjY2, yttria White powder, body-centered cubic structure d 5.03. Obtained by igniting yttrium or its salts. Sol in dil acids readily absorbs ammonia from the air displaces ammonia from ammonium salts, LD in rats 500 mg/kg i.p., Cochran et ai. Arch. Ind. Hyg. Qccup. Med. 1, 637 (1950),... 

Weigel but replied, and Weigel dealt his reply in 1772. Michael Friedrich Boehm, a pupil of Spielmann, rejected both Black s and Meyer s theories and said limestone became caustic by loss of water causticity was capacity for combining with water. C. F. Wenzel accepted Black s theory but (since he did not distinguish between fixed air and oxygen) could not understand why metallic calces displace ammonia from sal ammoniac like quicklime but do not effervesce with acids. Limestone loses weight on solution in acids, metallic calces do not, and this will never be explained. 

You could make it in the laboratory by heating any ammonium compound with any alkali. The alkali drives out or displaces ammonia from the compound. For example ... 

Displaced ammonia is eliminated by heating. A first titration with a standard sulfuric acid solution in the presence of phenolphthalein permits us to neutralize the sodium hydroxide in excess together with the first basicity of the formed carbonate. Then the titration is continued in the presence of helianthine. The added volume between the two color changes corresponds to the neutralization of the second basicity, that is, to the carbonate concentration. 

Bucherer reaction Bucherer discovered that the interconversion of 2-naphthol and 2-naphthylamine through the action of alkali and ammonia could be facilitated if the reaction was carried out in the presence of (HSO3]" at about 150 C. This reaction is exceptional for the ease with which an aromatic C —OH bond is broken. It is not of general application, it is probable that the reaction depends upon the addition of [HSO3]" to the normally unstable keto-form of 2-naphthol, and subsequent displacement of —OH by —NH2. 

Pyrrole is a colorless, slightly hygroscopic Hquid which, if fresh, emits an odor like that of chloroform. However, it darkens on exposure to air and eventually produces a dark brown resin. It can be preserved by excluding air from the storage container, preferably by displacement with ammonia to prevent acid-catalyzed polymerization. A review of the physical and theoretical aspects of pyrrole is found in Reference 4. Some physical properties of pyrrole are Hsted in Table 1. 

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. 

Amides, Imides, Alkamides. When zirconium tetrachloride reacts with hquid ammonia, only one chloride is displaced to form a white precipitate, insoluble in hquid ammonia (227) ... 

Halogen Reactions. Hydrolysis of chlorotoluenes to cresols has been effected by aqueous sodium hydroxide. Both displacement and benzyne formation are involved (27,28). o-Chlorotoluene reacts with sodium in Hquid ammonia to afford a mixture of 67% of o-toluidine [95-53-4] and 33% of yW-toluidine [108-44-1], C H CIN, as shown in equation 3 (29). 

The waste gas remaining after removal of ammonia and recovery of hydrogen cyanide contains enough hydrogen and carbon monoxide that it is flammable and has enough heat value to make it a valuable fuel. It is usually used to displace other fuel ia boilers. 

Hydroxyl Group. The OH group of cyanohydrins is subject to displacement with other electronegative groups. Cyanohydrins react with ammonia to yield amino nitriles. This is a step in the Strecker synthesis of amino acids. A one-step synthesis of a-amino acids involves treatment of cyanohydrins with ammonia and ammonium carbonate under pressure. Thus acetone cyanohydrin, when heated at 160°C with ammonia and ammonium carbonate for 6 h, gives a-aminoisobutyric acid [62-57-7] in 86% yield (7). Primary and secondary amines can also be used to displace the hydroxyl group to obtain A/-substituted and Ai,A/-disubstituted a-amino nitriles. The Strecker synthesis can also be appHed to aromatic ketones. Similarly, hydrazine reacts with two molecules of cyanohydrin to give the disubstituted hydrazine. 

A.mina.tlon. Amination describes the introduction of amino groups into aromatic molecules by reaction of ammonia or an amine with suitably substituted halogeno, hydroxy, or sulfonated derivatives by nucleophilic displacement. Although reaction and operational conditions vary, the process always involves the heating of the appropriate precursor with excess aqueous ammonia or amine under pressure. 

The original commercial source of E was extraction from bovine adrenal glands (5). This was replaced by a synthetic route for E and NE (Eig. 1) similar to the original pubHshed route of synthesis (6). Eriedel-Crafts acylation of catechol [120-80-9] with chloroacetyl chloride yields chloroacetocatechol [99-40-1]. Displacement of the chlorine by methylamine yields the methylamine derivative, adrenalone [99-45-6] which on catalytic reduction yields (+)-epinephrine [329-65-7]. Substitution of ammonia for methylamine in the sequence yields the amino derivative noradrenalone [499-61-6] which on reduction yields (+)-norepinephrine [138-65-8]. The racemic compounds were resolved with (+)-tartaric acid to give the physiologically active (—)-enantiomers. The commercial synthesis of E and related compounds has been reviewed (27). The synthetic route for L-3,4-dihydroxyphenylalanine [59-92-7] (l-DOPA) has been described (28). 

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