Ammonium chloride, hydrolysis

A certain amount of hydrolysis of the original acetamide to acid and ammonia always occurs, and the final amine always contains traces of ammonia. This is separated by extracting the mixed anhydrous hydrochlorides with absolute ethanol, which dissolves the amine hydrochloride but not the ammonium chloride filtration of the hot ethanolic extract removes the ammonium chloride, whilst the amine hydrochloride crystallises readily from the filtrate on cooling. 

The method of hydrolysis depends on the nature of the product. It is usually sufficient to add dilute sulphuric acid to the ethereal solution and to shake thoroughly, when the magnesium enters the aqueous solution, whilst the organic compound remains in the ether. Alternatively, however, the ethereal solution may be poured on to ice and water, and then treated with dilute sulphuric acid. Should the product be affected by this acid, the hydrolysis can be carried out with an aqueous solution of ammonium chloride. In the following examples the hydrolysis is usually shown as a simple double decomposition... 

In these cases, the use of weaker acids such as acetic acid or ammonium chloride permits the recovery of the desired alcohol. After the hydrolysis step is complete, the aqueous phase is separated from the organic phase and the product is then isolated. 

The most successful of these products contain high ratios of VP to DMAEMA and are partially quatemized with diethyl sulfate (Polyquaternium 11) (142—144). They afford very hard, clear, lustrous, nonflaking films on the hair that are easily removed by shampooing. More recendy, copolymers with methyl vinyl imidazoliiim chloride (Polyquaternium 16) (145) or MAPTAC (methacrylamidopropyltrimethyl ammonium chloride) (Polyquaternium 28) have been introduced. Replacement of the ester group in DMAEMA with an amide analog as in Polyquaternium 28 results in a resin resistant to alkaline hydrolysis and hence greater utility in alkaline permanent-wave and bleach formulations (see Quaternary ammonium compounds). 

Phenylstibine [58266-50-5] C H Sb, has been obtained by the reduction of phenyldiio do stihine [68972-61-2] CgH3l2Sb, (73) or phenyldichlorostibine [5035-52-9] 031130.2, (74) with lithium borohydride. It has also been prepared by the hydrolysis or methanolysis of phenylbis(trimethylsilyl)stibine [82363-95-9] C22H23Si2Sb (75). Diphenylstibine [5865-81-6] C22H22Sb, can be prepared by the interaction of diphenylchlorostibine [2629-47-2] C22H2QClSb, with either Hthium borohydride (76) or lithium aluminum hydride (77). It is also formed by hydrolysis or methanolysis of diphenyl (trimethylsilyl)stibine [69561-88-2] C H SbSi (75). Dimesitylstibine [121810-02-4] h.3.s been obtained by the protonation of lithium dimesityl stibide with trimethyl ammonium chloride (78). The x-ray crystal stmcture of this secondary stibine has also been reported. 

In 1959 a new non-protein L-a-amino acid was isolated from the seeds of Acacia willardiana and later from other species of Acacia-, it proved to be l-/3-amino-/3-carboxyethyluracil (977) (59ZPC(316)164). The structure was confirmed by at least four syntheses in the next few years. The most important involves a Shaw synthesis (Section 2.13.3.1.2e) of the acetal (975) and hydrolysis to the aldyhyde (976) followed by a Strecker reaction (potassium cyanide, ammonia and ammonium chloride) to give DL-willardiine (977) after resolution, the L-isomer was identical with natural material (62JCS583). Although not unambiguous, a Principal Synthesis from the ureido acid (978) and ethyl formylacetate is the most direct route (64ZOB407). 

When lithium di-n-butylcuprate is used, the yields are often improved by adding 1-bromobutane to the reaction mixture before hydrolysis with aqueous ammonium chloride. 

On hydrolysis in presence of alcohol it breaks up into glycocoll ester hj drochloride, ammonium chloride and formaldehyde. 

Merck s thienamycin synthesis commences with mono (V-silylation of dibenzyl aspartate (13, Scheme 2), the bis(benzyl) ester of aspartic acid (12). Thus, treatment of a cooled (0°C) solution of 13 in ether with trimethylsilyl chloride and triethylamine, followed by filtration to remove the triethylamine hydrochloride by-product, provides 11. When 11 is exposed to the action of one equivalent of tm-butylmagnesium chloride, the active hydrogen attached to nitrogen is removed, and the resultant anion spontaneously condenses with the electrophilic ester carbonyl four atoms away. After hydrolysis of the reaction mixture with 2 n HC1 saturated with ammonium chloride, enantiomerically pure azetidinone ester 10 is formed in 65-70% yield from 13. Although it is conceivable that... 

The pH at which basic iron(III) formate begins to precipitate depends upon several factors, which include the initial iron and chloride concentration a high concentration of ammonium chloride is essential to prevent colloid formation. It is important to use an optimum initial pH to avoid a large excess of free acid, which would have to be neutralised by urea hydrolysis, and yet there must be present sufficient acid to prevent the formation of a gelatinous precipitate prior to boiling the solution ideally, a turbidity should appear about 5-10 minutes... 

B) Hydrolysis of Ethyl Benzoylacefoacetate.—Thirty-two grams (0.6 mole) of ammonium chloride is dissolved in 150 cc. (8.3 moles) of water, in a 500-cc. Erlenmeyer flask, and 10 cc. (0.15 mole) of ammonia (sp. gr. 0.9) added. After the solution is warmed to 420, 58.5 g. (0.25 mole) of ethyl benzoylacetoacetate at 200 is added quickly, and the mixture shaken (Note 3). The flask is placed in a water bath at 420 for exactly ten minutes and then cooled rapidly by placing it in an ice bath. The solution is extracted twice with 100-cc. portions of ether, and the ether solution dried with anhydrous magnesium sulfate. The ether is distilled, and the residue distilled in vacuo the yield is 37.0-37.5 g. (77-78 per cent of the theoretical amount) of ethyl benzoylacetate boiling at 132-1370 at 4 mm., or 165-169° at 20 mm. 

The running of parallel reactions of hydrolysis, ammonolysis and depolymerization of apple pectin in aqueous solution of ammonia (IM) at 25 C were investigated. It was examined the effects of monovalent cations (Na, K", NH4 ) and divalent cations (Ca, Mg ) when they were added as chloride salts. It was found that the relative rates of the above mentioned reactions, depend on the nature and concentration of the added salts as well. The chlorides of sodium, potassium and calcium accelerate hydrolysis and depolymerization, while magnesium chloride delays these reactions. Ammonolysis was increased in cases of ammonium chloride addition. 

Water vapor is produced in the reaction, but the hydrolysis of the rare earth chloride formed is prevented by using excess ammonium chloride. After the reaction, the remaining ammonium chloride is removed completely by heating in vacuum at 300-320 °C. 

The extent of hydrolysis of the copolymers was determined by conductometric titration. The increase in carboxylate content was determined by difference, before and after hydrolysis. (The AMPS content of the polymers, where measured, was determined by colloid titration with poly [diallyl dimethyl ammonium chloride].)... 

When the imino compound XIV is heated with dilute hydrochloric acid, hydrolysis of the imino group takes place and there is formed ammonium chloride and D-glucoascorbic acid (XV). The latter displays all the chemical properties of L-ascorbic acid. 

Calculate the hydrolysis constant Kh for the ammonium chloride solution from Part III. Assume that [NH4+] is the same as the initial concentration of ammonium chloride. 

Anionicallv Activated Alumina. At this time we had also developed an interest in anionically activated alumina. These basic reagents were active in promoting alkylation(42), condensation(43) and hydrolysis(44) reactions. Thus, we impregnated alumina with sodium hydroxide and used this combination both with and without a phase transfer catalyst (benzyltriethyl ammonium chloride). When BTEAC was added, the conversion to ether was decreased and the formation of ester was noted. In the absence of a phase transfer catalyst, the ether became a minor product and methyl phenylacetate became the major product with coproduction of phenylacetic acid. This ester does not result from esterification of the acid as simple stirring of phenylacetic acid with Na0H/A1203 in methanol does not produce methyl phenylacetate. 

A nice example of the chemical similarity between imines and carbonyl compounds is the Strecker synthesis of amino acids. This involves reaction of an aldehyde with ammonia and HCN (usually in the form of ammonium chloride plus KCN) to give an intermediate a-aminonitrile. Hydrolysis of the a-aminonitrile then produces the a-amino acid. 

Hydrolysis An aliquot of the reaction mixture is quenched with saturated aqueous ammonium chloride solution eind extracted with ether, then injected on GC to verify that al the 4-bromobenzonifrile has been consumed, lodolysis An aliquot of the reaction mixture is added to a dry vial containing iodine after 10 min ether is added and the ethereal solution is washed with an aqueous solution of sodium thiosulfate. The organic phase is injected on... 

Combination with bipyridyl hgand in carbon tetrachloride followed by hydrolysis yields a molybdenum oxychloride bipyridyl complex of formula MoOCR(bipy). When mixed with ammonium chloride in acetonitrile and water, an oxychloride-acetonitrile complex, NIRfMoOCRCHsCN], is obtained. 

The synthesis of losartan potassium (1) by the process research chemists at Merck is outlined in the following (Griffiths et ak, 1999 Larsen et al., 1994). Phenyltetrazole (8) is protected as the trityl phenyltetrazole 9 (Scheme 9.3). Ortho-lithiation of 9 followed by quenching with triisopropyl borate afforded boronic acid 10 after treatment with aqueous ammonium chloride. Reaction of glycine (11) with methyl pentanimidate (12) in a methanol/water mixture yielded (pentanimidoylamino) acetic acid (13), which underwent a Vilsmeier reaction with phosphorous oxychloride in DMF followed by hydrolysis to give imidazole-4-carbaldehyde 14 in moderate yield. 

Mn203 films have been deposited on glass from an ammoniacal solution of Mn [33]. Ammonium chloride was added to decrease the pH and slow down the rate of hydrolysis. The initial product was believed to be Mn(OH)2, which oxidized in air to Mn203. 

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