Ammonium salts carbamate

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. 

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

Scheme 21 [Cp IrCl2]2-catalyzed amination of alcohols with ammonium salts, carbamates, amides, sulfonamides and primary heteroarylamines...

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 ... 

Other chemicals evaluated but not yet adopted commercially include organophosphorus compounds, triphenyltin compounds, quaternary ammonium salts, imidazoles, benzimidazoles, carbamates and the precocene anti-juvenile hormones [517]. Although none of the above has found use as an insect-resist agent, several have been used as antimicrobial agents for textiles. 

Sucii coefficients are needed for the effect of ammonium bicarbonate, carbamate, and hydrosulfide salts on the liquid phase activities of ammonia, carbon dioxide, and hydrogen sulfide. 

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. 

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

The assignment of the 1575 and 1488 cm 1 IR bands to an amine bicarbonate salt has been questioned by Battjes et al.44 NMR and FTTR were applied to show the formation of carbamates (-NH2COO ) instead of bicarbonates in the reaction of various amines with C02. The carbamate reacts with a second amine group with formation of an ammonium salt (equation F). 

Less familiar ammonium salts are the carbamate, NHfOCONH, and the dithiocarbamate NHtSCSNHj. These two salts are related to ammonium bicarbonate as shown ... 

The thiocyanate ion is sometimes regarded as a resonance hybrid of the two structures S—CsN and S—C=N Although organic compounds presumably related to each of the forms (of types R—S—(>s=N and R—N=C S) are known, the Raman spectra of solutions of ionic thiocyanates have been interpreted to show the presence of a feN link and the absence of a 0=S link, thus favoring the triple-bonded structure. Except for the ammonium salt, best made by heating ammonium dithio-carbamate (p. 236), ionic thiocyanates are best prepared by treatment of sulfur with the appropriate cyanide, either in solution or in fused state. (Selenocyanates may be prepared from selenium and ionic cyanides in the same way.)... 

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. "... 

Minakata and coworkers also reported the asymmetric aziridination reactions of electron-deficient olefins using cinchona-based PTCs 33-37 and N-chloro-N-sodio carbamate as an oxidant [32]. Moderate values of the ee were obtained. Comparative experiments revealed that the electron-deficient olefin bearing both the dimethylpyr-azole and the di-isopropylpyrazole groups turned out to be a better Michael acceptor than that bearing the oxazolidinone substituent. The modification of the R-substit-uent of the cinchona-derived anthracenylmethylated ammonium salts 35-37 did not have any effect on the enantioselectivity (Scheme 5.26). 

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