Carbamic acid, ammonium salt

Synonyms Ammonium aminoformate Carbamic acid, ammonium salt Carbamic acid, monoammonium salt... 

Carbamic acid, (2-aminoethyl)-. See Ethylenediamine carbamate Carbamic acid, (6-aminohexyl)-. See Hexamethylenediamine carbamate Carbamic acid, ammonium salt. See Ammonium carbamate Carbamic acid, 1H-benzimidazol-2-yl-. See Benzimidazole carbamate Carbamic acid, butyl-3-iodo-2-propynyl ester. See lodopropynyl butylcarbamate Carbamic acid, compd. with 1,2-ethanediamine Carbamic acid, compd. with ethylenediamine. See Ethylenediamine carbamate Carbamic acid, dibutyidithio-, zinc complex. 

Ammonium carbamate Carbamic xid, ammonium salt Carbamic acid, monoammonium salt EINECS 214-185-2 HSDB 485, Crystals bp approx. 60° freely soluble In H2O, soluble In EtOH. 

The reaction commences at about 120° the carbamic acid formed decomposes immediately into carbon dioxide and ammonia. The latter may form the ammonium salt with unreacted acid the ammonium salt also reacts with urea at temperatures above 120° to yield the amide ... 

The acid chloiide (chloioformamide [463-72-9] "uiea chloiide"), NH2COCI, and its salts have been prepared. Ammonium carbamate [1111 -78-OJ can be obtained as a white crystalline sobd by reaction of dry carbon dioxide and ammonia. It is an impurity in commercial ammonium carbonate [506-87-6] (see Ammonium compounds). Esters of carbamic acid are quite stable. The best known is the ethyl ester usually called urethane [51 -79-6],... 

A particularly useful synthesis of primary nitramines involves the nitration of the appropriate carbamate ester followed by ammonolysis with gaseous ammonia in diethyl ether. The ammonium salt of the nitramine precipitates in pure form and is carefully acidified to give the free nitramine. The corresponding carbamate esters are readily synthesized from the action of chlorocarboxylic acid esters on alkylamines in the presence of alkali hydroxides. 

Nitramine (161), the simplest member of the nitramines, can be prepared from ethyl carbamate (158) in three synthetic steps nitration of the latter with mixed acid or a solution of ethyl nitrate in concentrated sulfuric acid, followed by isolation of the resulting ethyl N-nitrocarbamate as the ammonium salt (159), hydrolysis with aqueous potassium hydroxide and subsequent acidification, yields nitramine (161). ... 

Upon dissolving the copolymer/catalyst mixture in ethylbutylamine (EtBuNH) the introduction of CO2 at atmospheric pressure results in formation of an equilibrium mixture of carbamic acid and the quaternary ammonium salt of carbamate. The carbamic acid serves to remove the copolymer from the metal center, at which time it precipitates in the ionic liquid and is isolated by filtration. The metal catalyst... 

Nitrogen NMR data have been obtained using both the low-abundance, spin = 1/2 N and the predominant spin = 1 N nuclei. Several different references have been used for nitrogen NMR including aqueous ammonia, ammonium salts, acetonitrile, nitric acid, and nitrates. Current opinion favors neat nitromethane, and the compilation of the known data for 1,4-oxazines (Table 6) is expressed with respect to this reference and arranged in order of the observed chemical shift. For the C-labeled compound 87, carbamate rotamers lead to two separate signals and the value of 7c n can be determined -283.98 (d, J 9) and -284.46 (d, 7 11) <2001JOC8010>. 

The detailed mechanism of sarcosine NCA polymerisation may be radically modified by a change of solvent. For example, in dimethyl formamide this reaction is first order with respect to growing ends [see e. g. ref. (44)] instead of being second order as in nitrobenzene. The higher acidity of the former solvent reduces the basicity of the dissolved amine and, therefore, destroys its catalytic action. This effect influences also the equilibrium between the amine and the dissolved C02. In nitrobenzene, the carbamic acid produced is associated with the free amine forming the respective ammonium salt (ion-pairs), whereas in the more acidic dimethyl formamide it exists as an un-ionised acid. 

Ammonium carbamate is prepared from dry ice and liquid ammonia [14]. These conditions are very similar to the conditions under which we have observed the formation of amine salts. To some readers, ammonium carbamate may seem to be an exotic compound. In fact, it is manufactured industrially on a multiton scale, because on heating (usually at 100-185°C) ammonium carbamate is converted to urea and water [14-16]. Urea is important for both the agricultural and the plastics industries. The ammonium carbamate is not always isolated during urea preparation. Instead, the reactions are carried out under conditions where the carbamate is just an intermediate. Ammonium carbamate is only moderately stable and it gradually loses ammonia in air. Although the data are sparse, the rate of decomposition of carbamates in solution seems to decrease as the volatility of the parent amine decreases [17]. Free carbamic acids in solution do not decompose spontaneously to free amine and C02. Instead, the acid ionizes by reaction with water the proton is transferred from the hydronium ion to the amine and then decomposition occurs [17]. Acids catalyze the decomposition. 

Of these, the best known are the ammonium salt of (3), which is termed carbamic acid, and (4), the important compound urea or carbamide. 

A similar compound, viz., carbamic acid, stands intermediate between carbonic acid and carbamide (urea). It is not known, however, as such but as the ammonium salt or as an ester. 

The product, methyl ammonium methyl di-thio-carbamate, is an alkyl ammonium salt, corresponding to the ammonium salt, of methyl di-thio-carbamic acid as shown by the following formulas ... 

Even though formic anhydride is not a stable compound (see p. 723), amines can be formylated with the mixed anhydride of acetic and formic acids (HCOO-COMe) or with a mixture of formic acid and acetic anhydride. Acetamides are not formed with these reagents. Secondary amines can be acylated in the presence of a primary amine by conversion to their salts and addition of 18-crown-6. The crown ether complexes the primary ammonium salt, preventing its acylation, while the secondary ammonium salts, which do not fit easily into the cavity, are free to be acylated. Dimethyl carbonate can be used to prepare methyl carbamates in a related procedure. A-Acetylsulfonamides were prepared from acetic anhydride and a primary sulfonamide, catalyzed by Montmorillonite KlO-FeO or sulfuric acid. "... 

A hydrotrope is a compound that helps other compounds normally not very soluble in water to dissolve in water.) The one used was (2.26). Pyrolysis of the carbamate (obtained in 90-96% yield) would lead to the isocyanate. This type of reaction can also be carried out in 95% yield using TV-bromosuccinimide and sodium methoxide in methanol or with bromine and sodium hydroxide.67 This suggests the possibility of generating the bromine or iodine during the reaction by electrolysis of sodium bromide or sodium iodide so that no waste salts result. The starting amides can be made by heating the ammonium salts of the acids. This... 

M, Carbamic Acid. Aminoformic acid aminometban -dcirid, NHjCOOH. Not known in the free state. Its salts tccur is blood and urine of mammals, la salts, e.g ammonium carbamate, and its esters, such Kite ethyl ester (urethan), are entered separately. 

Ammonium dithiocarbamate Ammonium sulfocarb-amate Carbamic acid, dithio-, monoammonium salt Dithiocarbamic acid monoammonium salt EINECS 208-166-8 HSDB 5675 NSC 202959. 

AI3-25347 Ammonia sesquicarbonate Ammonium carbonate Ammoniumcarbonat Carbonate d ammoni-aque Carbonic acid, diammonium salt Caswell No. 042 CCRIS 7328 Diammonium carbonate EINECS 208-058-0 ERA Pesticide Chemical Code 073501 HSDB 6305 Salt of Hartshorn. Also typically contains ammonium carbamate. Crystals mp = 58 (dec) vaporizes at about 60° incompatible with acids and acid salts soluble in H2O (25 g/100 ml). 

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