Ammonium salts reaction with urea

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 ... 

CP esters are generally prepared as the ammonium salt [9038-38-4] by the reaction of cellulose with phosphoric acid and urea at elevated temperatures (130—150°C). The effects of temperature and urea/H PO /cellulose composition on product analysis have been investigated (33). One of the first commercially feasible dameproofing procedures for cotton fabric, the Ban-Flame process (34,35), was based on this chemistry. It consists of mixing cellulose with a mixture of 50% urea, 18% H PO, and 32% water. It is then pressed to remove excess solution, heated to 150—175°C for 5—30 minutes, and thoroughly washed (36). 

Silylation of amino acids such as r-leucine 180 with TCS 14 gives rise to the O-silylated ammonium salt 181, which reacts selectively with triphosgene and triethylamine to afford the isocyanate 182. Subsequent reaction of 182 with primary amines such as free r-leucine 180 or secondary amines such as N-BOC-pi-perazine 184 affords the ureas 183 and 185 in 49% or 77% overall yield, respectively [10] (Scheme 4.7). 

In 1994, Mansuy and coworkers found that a simple ammonium salt, like ammonium acetate alone, is a very efficient cocatalyst for the metalloporphyrin-catalyzed epoxidation of simple alkenes by hydrogen peroxide ". Bases like sodium carbonate, sodium acetate or tetrabutylammonium hydroxide turned out to promote the porphyrin-catalyzed epoxidation without any other additive. Adducts of hydrogen peroxide (with Na2C03, urea, MesNO, PhsPO), which turned out to be particularly useful for reactions in which the concentration of H2O2 in solution needs to be controlled at a fixed level, have been employed by Johnstone and coworkers. 

Phenylacetamide has been obtained by a wide variety of reactions from benzyl cyanide with water at 250-260° 6 from benzyl cyanide with water and cadmium oxide at 240° 6 from benzyl cyanide with sulfuric acid 7 8 by saturation of an acetone solution of benzyl cyanide with potassium hydrosulfide 9 from benzyl cyanide with sodium peroxide 10 by electrolytic reduction of benzyl cyanide in sodium hydroxide 11 from ethyl phenyl-acetate with alcoholic 12 or aqueous 13 ammonia from phenyl-acetic acid with ammonium acetate 14 or urea 15 from diazoacetophenone with ammoniacal silver solution 16 from phenyl-acetic acid imino ether hydrochloride and water 17 from acetophenone with ammonium poly sulfide at 215° 18 from benzoic acid 19 and by heating the ammonium salt of phenyl-acetic acid.20... 

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. 

This reaction takes place in a matter of seconds and produces significantly more fluorescence than the diacetylmonoxime fluorophors. Excess reagent is quickly hydrolyzed to form nonfluorescent water soluble products. Secondary, tertiary, and aromatic amines did not react with fluram to produce any measureable fluorescence. The reaction did not occur when ammonia and ammonium salts were tested for fluorescence. Mass spectrometry of an actual field sample confirmed that the substitution product is the fluorescent species that is shown above. Further mass spectra studies indicated that dimethyl-urea is not produced during this reaction. This was later confirmed by introducing known quantities of the urea and little or no fluorescence was noted. These tests indicate that Fluram does react with the primary amine intermediate on the adsorbent according to the above equation, and that monomethyl amine and other primary aliphatic amines would interfere. 

Second-order reactions of type II are probably among the most common of all reactions studied. A few typical examples are the gas-phase formation of hydrogen iodide, II2 + I2 2HIthe reactions of free radicals with molecules, for example, H + Br2 HBr + H the famous synthesis of urea from NH4 and CNO ions the hydrolysis of organic esters in non-aqueous media and the reaction of tertiary alkyl amines with alkyl halides to produce quaternary ammonium salts, R3N + R X — R RsN+ +... 

It is well known that halomethyleneiminium salts, often prepared in situ (see Section 2.1.2.2) react with ammonium salts, primary amines, secondary amides, urea and IV-substituted ureas to afrbrd amidinium salts, from which the free amidines can be obtained by addition of bases. > 4 Some recent results are given below. Dimethylformamide chloride and other 7V,iV-disubstituted formamide chlorides were reacted with acetanilides, chloroacetanilides, 6-aminopenam derivatives, 2-aminopyrimidine, 4-aminouracil, 2-amino-4-chloropyridazine, 2-aminothiazole, 2-aminobenzothiazole and thiobenzamides to give the amidines via the amidinium salts. In the reaction of MA -disubstituted formamide chlorides with thiobenzamides the solvent seems to be decisive for the course of the reaction. In tertiary formamides the thiobenzamides are desulfurized to nitriles, whereas in CHCI3 or CCI4 amidinium salts (296 Scheme 45) are formed. From trimethylsilyl isocyanate and the fluorinated amine (297) the /V-fluorocarbonylamidine (298) is accessible. ... 

High purity submicrometer (100-150 A) powders of BN have been synthesized in the range —75 to -t-750°C, by means of reactions of borax and carbamide (urea) in ammonia. Metal borohydrides and boron halides in NH3 and ammonium salts with benzene solutions of BCI3 were also studied. BN ceramic aerogels were also described. ... 

Chlorobenzene is employed in the synthesis of certain amino-containing vat dye intermediates. When reacted with phthalic anhydride, the product is 2-chloroanthraquinone, which, with ammonia, is converted readily into 2-aminoanthraquinone (61). Other routes include replacement of halogen by amino groups, with ammonia or ammonium salts of urea, and alkyl- and aryl amines to afford secondary amines. Modification of the amino group by alkylation, with dimethyl sulfate, alkyl halides or esters of toluenesul-fonic acids, is of synthetic value. Arylation of the amino groups is of importance only in the reaction between aminoanthraquinones and nitro- or chloroanthraquinones to yield dianthraquinonylamines, or anthrimides48. For example, the reaction between 62 and 63 yields 64, which can then be converted into carbazole 65, Cl Vat Brown R (Scheme 14). Amination of haloanthraquinones such as l-amino-4-bromoanthraquinone-2-sulfonic acid (bromamine acid) (66), prepared from 1-aminoanthraquinone, is of industrial use. 

Reaction of the derivative 98 with a hot methanolic solution of ammonium acetate, containing a small amount of MeONa, gives the 2-aminopyrrole 99 (Eq. (15)). The same product was obtained when the ammonium salt was replaced by urea or thiourea (97EJC105). 

When N2 and O2 molecules collide near a bolt of lightning, they can absorb enough electrical energy to produce molecules of NO. An NO molecule is quite reactive because it contains one unpaired electron. NO reacts readily with O2 to form nitrogen dioxide, NO2. Most NO2 dissolves in rainwater and falls to the earth s surface. Bacterial enzymes reduce the nitrogen in a series of reactions in which amino acids and proteins are produced. These are then used by plants, eaten by animals, and metabolized. The metabolic products are excreted as nitrogenous compounds such as urea, (NH2)2CO, and ammonium salts such as NaNH HPO. These can also be enzymatically converted to ammonia, NH3, and amino acids. 

A cationic starch can be prepared by blending a condensate of formaldehyde plus an inorganic ammonium salt with starch and heating at 80 °C for up to 1 h.1316 A great interest was developed with urea-formaldehyde resins that were made to react with such polyalcohols as starch.1317-1319 It was reported that the reaction of starch with urea-formaldehyde resin required an acidic catalyst592,1320-1325 and the use of such dispersants as polyphosphates.1326 Ammonium metaphosphate catalyzed the reaction without the addition of any other acid catalyst.1327 A product that formed a paste was produced by controlling the proportion of starch to aldehyde (either up to 20% of formaldehyde or up to 30% of acetaldehyde) and urea (up to 15%) at pH 2 1.1328... 

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