Ammonia hydrolysis reaction

A portion of the monophenylurea then reacts with the aniline (formed by the hydrolysis of the aniline hydrochloride or cyanate) to give diphenyl-urea and ammonia, a reaction which probably proceeds through the... 

This is an example of an ammonolytic reaction ia which a chemical bond is broken by the addition of ammonia. It is analogous to the hydrolysis reactions of water. An impressive number of inorganic and organic compounds undergo ammonolysis. 

A common technique for minimizing secondary amine formation is to carry out the hydrogenation in the presence of ammonia (21,23,42). Ammonia is thought to complete with the primary amine in attack on the intermediate imine. Anhydrous ammonia is preferred to prevent hydrolysis reactions,... 

Solvents influence the hydrogenation of oximes in much the same way as they do hydrogenation of nitriles. Acidic solvents prevent the formation of secondary amines through salt formation with the initially formed primary amine. A variety of acids have been used for this purpose (66 ), but acids cannot always be used interchangeably (43). Primary amines can be trapped also as amides by use of an anhydride solvent (2,/5,57). Ammonia prevents secondary amine formation through competition of ammonia with the primary amine in reaction with the intermediate imine. Unless the ammonia is anhydrous hydrolysis reactions may also occur. 

Conversion of Amides into Carboxylic Acids Hydrolysis Amides undergo hydrolysis to yield carboxylic acids plus ammonia or an amine on heating in either aqueous acid or aqueous base. The conditions required for amide hydrolysis are more severe than those required for the hydrolysis of add chlorides or esters but the mechanisms are similar. Acidic hydrolysis reaction occurs by nucleophilic addition of water to the protonated amide, followed by transfer of a proton from oxygen to nitrogen to make the nitrogen a better leaving group and subsequent elimination. The steps are reversible, with the equilibrium shifted toward product by protonation of NH3 in the final step. 

A very efficient and universal method has been developed for the production of optically pue L- and D-amino adds. The prindple is based on the enantioselective hydrolysis of D,L-amino add amides. The stable D,L-amino add amides are effidently prepared under mild reaction conditions starting from simple raw materials (Figure A8.2). Thus reaction of an aldehyde with hydrogen cyanide in ammonia (Strecker reaction) gives rise to the formation of the amino nitrile. The aminonitrile is converted in a high yield to the D,L-amino add amide under alkaline conditions in the presence of a catalytic amount of acetone. The resolution step is accomplished with permeabilised whole cells of Pseudomonas putida ATCC 12633. A nearly 100% stereoselectivity in hydrolysing only the L-amino add amide is combined with a very broad substrate spedfidty. 

The hydrolysis reactions of ammonium ions to give ammonia and carbonate to give hydrogen carbonate result in a pH of about 9, depending on the temperature. This pH is suitable for precipitating a large number of metal hydroxides. 

This enzyme [EC 4.1.99.1], also known as L-tryptophan indole-lyase, catalyzes the hydrolysis of L-tryptophan to generate indole, pyruvate, and ammonia. The reaction requires pyridoxal phosphate and potassium ions. The enzyme can also catalyze the synthesis of tryptophan from indole and serine as well as catalyze 2,3-elimination and j8-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. 

Calcium cyanamide partially hydrolyzes to calcium hydrogen cyanamide, CaHCN2. The final hydrolysis products are calcium carbonate and ammonia. The reaction is slow, occurring in moist soil ... 

Silica Nanoparticles. The base-catalyzed hydrolysis of silicon aikoxides in microemulsions produces nanoparticles (20-39). Aqueous ammonia has been used primarily as the base, with AOT and nonionic polyoxyethylene ethers as the main surfactants. Figure 2.2.6 presents a flow diagram for the synthesis of pure silica (23-32) the microemulsion is first prepared and then the alkoxide is added. As can be seen from Table 2.2.1, the microemulsions include the systems AOT/ isooctane/water/ammonia, AOT/toluene/water/ammonia, NP-5/cyclohexane/water/ ammonia, and NP-4/heptane/water/ammonia. Typical reaction times are l -5 days. Various modified silica nanoparticles have also been prepared, including hydropho-... 

Reaction (39) is a hydrolysis of hexamine resulting in the formation of formaldehyde and ammonia, and reaction (40) consists of the oxidation of formaldehyde with nitric acid. 

Meszaros, Hermecz et al. transformed the quaternary 6,7.8,9-tetrahydro-pyrido[1.2-u]pyrimidinium salts (204) with acid to the carboxylic acids (205 R1 = H)257 and with sodium hydrogen carbonate solution to the l,6,7,8-tetrahydropyrido[l,2- ]pyrimidines (205 R = alkyl).7x2 8 From the alkaline hydrolysis reaction mixture, compounds 206 and 207 were also isolated.133 The quaternary salt (204 R = Me) was transformed with hydrazine hydrate to 6-methylpiperidone and with ammonia to 6-methyl-4-oxo-6.7,8,9-tetrahydro-4//-pyrido[1.2- ]pyrimidine-3-carboxamide and its A-methyl derivative.133... 

Amides undergo an acid- or base-catalyzed hydrolysis reaction with water in the same way that esters do. Just as an ester yields a carboxylic acid and an alcohol, an amide yields a carboxylic acid and an amine (or ammonia). The net effect is a substitution of -N by -OH. This hydrolysis of amides is the key process that occurs in the stomach during digestion of proteins. 

The mechanism of the reaction is not certain but hydrolysis of the salt may yield the primary amine (5), formaldehyde and ammonia. A hydride ion transfer then probably occurs between the benzylamine and the protonated aldimine (6), derived from formaldehyde and ammonia. Hydrolysis of the resulting aromatic aldimine (7) then yields the required aldehyde. 

Hydrolysis with alkali. When nitriles are treated with 20-40 per cent sodium or potassium hydroxide solution, there is no reaction in the cold upon prolonged boiling hydrolysis proceeds comparatively slowly (compare primary amides which are rapidly hydrolysed) to the sodium salt of the acid and ammonia. The reaction is complete when ammonia is no longer evolved ... 

In 1948, Rochow252,383 discovered that the hydrolysis product of Me2GeCl2 was easily dissolved in water in contrast to the hydrolysis product of Mc2SiCl2- The solution was evaporated without leaving any residue, indicating the formation of volatile hydrolysis products. This was also observed in the reaction of Me2GeCl2 with aqueous ammonia. This led Rochow to the conclusion that the hydrolysis reaction of Me2GeCl2 was reversible. 

Difluoroamine (fluorimide) was discovered by Kennedy and Colburn as a by-product accompanying tetrafluorohydrazine in the reduction of NF3 by arsenic1 and arsine. It was found to be a product of hydrolysis of fluorinated urea80 and was detected in trace amounts among the products of fluorination of ammonia.8 Reactions to be considered for preparative purposes include the following (1) reduction of tetrafluorohydrazine,4 (2) hydrolysis of difluorourea, (3) protonation of trityldifluoroamine, (4) hydrolysis of difluorosulfamide,7 and (5) hydrolysis of isopropyl difluorocarbamate.8... 

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