Acetic acid ammonium salt hydrolysis

Another application of this method is the stereoselective addition of (7 )-2-hydroxy-l,2,2-triphenylethyl acetate, via the lithium enolate, to propenal (acrolein) which affords mainly the ester 13 (d.r. 92 8). When the acid, obtained in the subsequent alkaline hydrolysis, is converted into the ammonium salt derived from (.S)-l -phenylethylaminc, and the salt recrystallized once, then the amine liberated (/f)-3-hydroxy-4-pentenoic acid is obtained in 41 % yield [relative to the (/ )-acetate] and >99.8% ee82. 

Treatment of the ammonium salt of 3,5-dinitro-1,2,4-triazole (113) with hydrazine hydrate leads to selective reduction of one of the nitro groups to yield 3-amino-5-nitro-1,2,4-triazole (ANTA) (114), a high performance explosive (calculated VOD 8460 m/s) possessing thermal stability (m.p. 238 °C) and an extremely low sensitivity to impact. ANTA (114) is also synthesized from the nitration of 3-acetyl-l,2,4-triazole with anhydrous nitric acid in acetic anhydride at subambient temperature followed by hydrolysis of the acetyl functionality. The ammonium salt of 3,5-dinitro-l,2,4-triazole (113) is itself a useful explosive which forms a eutectic with ammonium nitrate. ... 

Ammonium salts of strong acids, such as NH4C1 or NH4N03, however, can lower the pH and encourage the hydrolysis of clays. Salts of weak acids, such as acetates, can, conversely, increase the pH with possible precipitation of metal hydroxides - an effect countered, however, by the complexation of metals by acetate. This complexation also inhibits the reabsorption of released metals. Ammonium acetate (1 moll-1, pH 7) has, therefore, been widely adopted as a soil extractant and recommended by a consortium of European experts for extractable metal trials under the auspices of Bureau Communautaire de Reference (BCR) of the European commission (Castilho and Rix, 1993 Ure et al., 1993a, b). 

Preparative Methods the most convenient preparation of (/ ,/ )-stilbenediamine is described in Organic Syntheses." Condensation of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid (eq 1) produces a spirocyclic 2//-imidazole (mp 105-106 °C). Reduction with Lithium in THF/NH3 followed by an ethanol quench and hydrolysis with aqueous HCl (eq 2) affords the racemic diamine as a pale yellow solid (mp 81-82 °C). Resolution is achieved by multiple recrystallizations of the tartaric acid salts ifom water/ethanol. The sulfonamides are prepared by reaction of the enantiomeri-cally pure diamine with the appropriate anhydride or sulfonyl chloride in CH2CI2 in the presence of Triethylamine and a catalytic amount of 4-Dimethylaminopyridine (eq 3). 

Preparative Methods (i) preparation of racemic DPEN and its optical resolution Reaction of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid at reflux temperature gives a cyclic bis-imine (1) (eq 1). Stereoselective reduction of the bis-imine with lithium in THF-liquid ammonia at —78 °C followed by addition of ethanol, then hydrolysis with hydrochloric acid and neutralization with sodium hydroxide produces the racemic diamine (2). Recrystallization of the l-tartaric acid salt from a 1 1 water-ethanol mixture followed by neutralization with sodium hydroxide, recrystallization from hexane results in (5,5)-DPEN (3) as colorless crystals. 

In order to illustrate the hybrid ion theory, we shall compare ammonium acetate with an amino acid of which the acid and basic dissociation constants are respectively the same as those of acetic acid and ammonium hydroxide. We know that in 0.1 molar solution, ammonium acetate is 0.5% hydrolyzed and the salt is 99.5% ionized. If we employ the same equation (40 in Chapter One) to calculate the degree of hydrolysis of the amino acid, we find that it too is 0.5% hydrolyzed. Thus it appears logical to assume that the remainder of the ampholyte is present in the ionogenic form. 

Capillary phenomena may arise from other causes. Thus a solution of ammonium acetate turns both red and blue litmus papers violet. The drops are more bluish in the center and more red at the edge. It appears that the paper hinders the diffusion of ammonium hydroxide to a greater extent than it does the diffusion of acetic acid. The effect is even more evident when the reaction is produced with lead acetate. Around the center of the drop is found a blue region (adsorption of lead hydroxide) which is surrounded by a red region due to the diffusion of the acetic acid. These observations account for the discrepancy found in medical books regarding the reaction of lead acetate. It is impossible to determine accurately the reaction of this salt with litmus paper. It can be done, however, with methyl red solutions. The reaction resulting from the hydrolysis of salts such as sodium acetate and ammonium chloride is demonstrated readily by means of indicator papers. 

The formula assigned to gallotannic acid is in accord with its reactions. The acid is converted into gallic acid by hydrolysis, forms a penta-acetyl derivative when heated with acetic anhydride, and is converted into the amide and the ammonium salt of gallic acid when boiled with a solution of ammonia. 

All the diarylstibinic acids are solids, and their method of preparation has an influence upon their solubility, eg, the hydrolysis of di-phenylstibinic chloride by ammonium hydroxide yields an acid which is insoluble in ammonium hydroxide or sodium carbonate, but dissolves in sodium hydroxide, whilst solution of the chloride in sodium hydroxide gives a stibinic acid on acidification with acetic acid which dissolves in all the foregoing alkalis. The secondary acids also differ from the primary acids in their action towards hydrochloric acid and ammonium chloride diphenylstibmic acid is insoluble in concentrated hydrochloric acid, and m hot dilute hydrochloric acid its solutions do not give a double salt with ammonium chloride, but pyridine hydrochloride precipitates diphenylstibmic chloride as a double salt. Nitration of the secondary stibinic acids yields nitro-acids containing the nitro-group in the meia-position to the antimony. Reduction of the secondary acids yields stibinoxides. Mercuric chloride converts diphenylstibmic acid in methyl alcohol-hydrogen chloride solution into phenylmercuric chloride and antimony trichloride. 

As with hemiacetal- and acetal-forming reactions, imine formation is reversible acid-catalyzed hydrolysis of an imine gives a 1° amine and an aldehyde or a ketone. When one equivalent of acid is used, the 1° amine, a weak base, is converted to an ammonium salt. 

Although the addition of hydrophobic ammonium salts has little affect upon the rate of hydrolysis of 4-nitrophenyl acetate catalysed by methacrylic acid-A-methacryloylhistamine co-polymer there is a marked increase when 4-nitrophenyl hexanoate is used as the substrate. It is suggested that the polymer-bound ammonium ions facilitate subsequent binding of the substrate. ... 

Chitin is insoluble in water and barely soluble in acidic media (forming ammonium salts). Heating in acid or alkahne solutions leads to the hydrolysis of bound N-acetyl-n-glucosamine with the formation of n-glucosamine and acetic acid. Heating under acidic conditions causes partial depolymerisation of chitin through the hydrolysis of P-glycosidic bonds. In alkaline solutions, depolymerisation occurs to a lesser extent. 

In working up a complete reaction mixture, or filtrates from the amide, it is advantageous to remove water, organic solvent, and as much of the volatile ammonium sulfide as possible by evaporation to dryness on a water bath or by distillation under reduced pressure the residue contains the amide mixed with excess sulfur, small amoimts of the ammonium salt of the acid, and other by-products. Separation of the amide from the sulfur is accomplished usually by extraction with a solvent such as hot water, ethanol, or carbon tetrachloride which will dissolve the amide but not the sulfur. When such a separation is not feasible, it may be necessary to hydrolyze the amide to the acid by heating with aqueous or ethanolic alkali or with a mineral acid. A mixture of acetic acid and concentrated hydrochloric acid is particularly effective for the hydrolysis of insoluble amides. 

Our compatriot N. A. Menshutkin made a great contribution to the development of the kinetics. In 1877 he studied in detail the reaction of formation and Iqrdrolysis of esters from various acids and alcohols and was the first to formulate the problem of the dependence of the reactivity of reactants on flieir chemical structure. Five years later when he studied the hydrolysis of tert-zmy acetate, he discovered and described the autocatalysis phenomenon (acetic acid formed in ester hydrolysis accelerates the hydrolysis). In 1887-, studying the formation of quaternary ammonium salts from amines and alkyl halides, he found a strong influence of the solvoit on the rate of this reaction (Menschutkin reaction) and stated the problem of studying the medium effect on the reaction rate in a solution. In 1888 N. A. Menschutkin introduced the term chmical kinetics in his monograph Outlines of Development of Chemical Views. ... 

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