Synthesis of ammonium cyanate and urea from – ScienceDirect

W0hler in 1824 who employed its salt, ammonium cyanate, in his famous synthesis of urea …

Catalytic process for the production of urea and ammonium cyanate ..

Table 2: Nitrogen Oxide Reduction Using Ammonia and Urea Only 10 - 20% of the gas is converted to ammonia through the synthesis of nitrogen and hydrogen.

This was an early discovery of isomerism, since ureahas the formula CO(NH) and ammonium cyanate has the formula NHCNO.

…anhydrous ammonia, ammonium nitrate, and urea

are formed by the action of carbonyl chloride on ammonium chloride (at 400° C.), or on salts of primary amines. They are readily hydrolysed by water, and combine with bases to form alkyl ureas, and with alcohols to form carbamic esters. Substituted urea chlorides are formed by the direct action of chlorine (F. D. Chattaway and D. F. S. Wunsch, 1909, 95, p. 129). Urea chloride, NH 2 COC1 (L. Gattermann, 1888, 244, p. 30), melts at 50° C. and boils at 61-62° C. In the presence of anhydrous aluminium chloride it reacts with aromatic hydrocarbons to form the amides of aromatic acids. H 2 NCONHNO 2, prepared by adding urea nitrate to wellcooled concentrated sulphuric acid (J. Thiele and A. Lachmann, 1895, 288, p. 281), is a crystalline powder, soluble in water, and which decomposes on heating. It is a strong acid and is stable towards oxidizing agents. Diazomethane converts it into the methyl derivatives of isocyanic acid, and nitramide, NH2N02. or semicarbazide, NH 2 CONHNH 2, is best prepared from hydrazine sulphate and potassium cyanate (J. Thiele and 0. Stange, 18 94, 2 7, p. 31). It may also be obtained by reducing nitrourea in acid solution with zinc dust. It crystallizes in prisms, which melt at 96° C., and are easily soluble in water. It reduces Fehling's solution in the cold. It reacts with carbonyl compounds, giving and in consequence is frequently used for characterizing such substances. N H2CONHOH, is produced from hydroxylamine and cyanic acid (W. F. Dresler and R. Stein, 1869, 150, p. 242), or from ammonium hypochlorite and potassium cyanate (A. Hantzsch, 1898, 299, p. 99). It crystallizes in needles, which melt at 128-130° C., and is decomposed on long heating. It is readily soluble in water and reduces warm silver solutions. Hyponitrous acid is formed by passing nitrous fumes into its methyl alcohol solution.

The Wöhler synthesis is the conversion of ammonium cyanate into urea

Results of studies on the metabolic fate of dietary ammonium citrate (Foster et al., 1939) and intravenously-administered ammonium lactate (Duda & Handler, 1958) in rats showed that urea synthesis represented a nearly constant fraction of the administered ammonia over a large concentration range.

Wijhler synthesis could be reversed and urea converted back to ammonium cyanate was not ..


Industrial Chemical - Carbon Disulphide Manufacturer …

NH 2 CONH000H 31 formed by the action of acetic anhydride on urea, crystallizes in needles which melt at 212° C. and, on heating, strongly decomposes into acetamide and cyanuric acid. CH 3 NHCONH000H 31 is formed by the action of potash on a mixture of bromine (I mol.) and acetamide (2 mols.) (A. W. v. Hofmann, 1881, 14, p. 2725), or of methylamine on acetylurethane (G. Young, 18 9 8, 73, p. 364). When heated with water it is decomposed into carbon dioxide, ammonia, methylamine and acetic acid. or a-bromisovaleryl urea, NH 2 C0NHC0CHBrCH(CH 3) 2, has been introduced as an hypnotic; its action is mild, and interfered with by the presence of pain, cough or delirium.

Discoveries In The Field Of Chemistry | Chemistry …

or sulphocarbamide, CS(NH 2) 2, is formed by prolonged fusion of ammonium thiocyanate (E. Reynolds, 1869, 150, p. 224), by passing sulphuretted hydrogen into an ethereal solution of cyanamide (E. Baumann, 1873, 6, p. 1 375), or by heating isopersulpho-cyanic acid (F. D. Chattaway, 1897, 71, p. 612). It crystallizes in thick prisms which melt at 180° C. and is readily soluble in water. When heated for some time with water to 140° C. in a sealed tube, it is transformed into ammonium thiocyanate, a similar result being obtained by heating the base alone for some hours to 160-170° C. On heating alone for some hours to r70-180° C. it is converted into guanidine thiocyanate. It is hydrolysed by alkalis, giving carbon dioxide, ammonia and sulphuretted hydrogen. It is readily desulphurized by silver oxide, mercuric oxide or lead oxide. Potassium permanganate oxidizes it to urea (R. Maly, 1890, II, p. 278). It acts as a weak base and forms salts with one equivalent of an acid.

Ammonia (EHC 54, 1986) - INCHEM

The synthesis of urea from cyanic acid and ammonia through the intermediate of is known as the Wöhler synthesis. Different sets of reactants have been tried for this reaction. Other method has also been explored where a mixture of and NH4Cl when heated and cooled, and the resulting urea is precipitated with . It has been reported that ammonia and cyanic acid (or isocyanic) acid can form two sets of products, or urea, each one is readily converted into the other or forms an equilibrium in solution. This reaction has been applied for the preparation of urea and thiourea derivatives.