Sodium cyanate

A mixture of 26.5 g, (0.25 mol) of finely powdered anhydrous sodium carbonate and 35 g. (0.58 mol) of urea is heated in a tail-form crucible as rapidly as possible with two M6ker or similar burners. Sodium cyanate melts at a higher temperature than potassium cyanate therefore, smaller quantities are xised, and stronger heating is necessary. Otherwise, the fusion operation is the same as that for potassium cyanate. It is difficult to obtain a carbonate-free melt of sodium cyanate, but the carbonate may be 

Since sodium cyanate is less soluble in water than potassium cyanate, the soluble impurities are more easily removed by crystallization. Further, because an alcohol precipitation would require more alcohol per gram for sodium cyanate than for potassium cyanate, the recrystallization is made from water alone. The yield is lower but the product is pure. 

A solution of sodium cyanate is made by mechanically stirring the finely powdered material with water at 50° (100 ml. of water for each 15 g. of material). Glacial acetic acid is added until the solution is neutral to phenol-phthalein. After filtration, the solution is allowed to stand in a refrigerator for a few hours. Then the crystals are collected and washed with alcohol. Yield 5 g. (33 per cent). The substance is thoroughly dried in a vacuum desiccator to avoid partial hydrolysis on storage. 

Carbonate. The tip of a glass rod is touched to the surface of the cyanate melt, and the cap of solid that forms is dissolved in 2 ml. of distilled water. Ten drops of 0.1 M barium nitrate is added. The presence of carbonate ion is indicated by the formation, within a minute, of a precipitate of barium carbonate. 

Ammonium Ion and Urea. To a solution of 0.1 g. of the cyanate in 2 ml. of distilled water is added a few drops of 0.1 M mercury(II) chloride solution. The mixture is then made alkaline with sodium hydroxide solution. If a white precipitate is obtained, ammonium ion or urea is present, or both. A yellow precipitate of mercury(II) oxide indicates the substantial absence of these impurities. 

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Wohler s classical synthesis of urea from ammonium cyanate may be carried out by evaporating solutions of sodium cyanate and ammonium sulphate ... 

Method 1 (from the amine hydrochloride). Dissolve 13 Og. of anihne hydrochloride in 200 ml. of water and filter, if necessary, from any insoluble matter into a 350 ml. beaker or conical flask. Add a solution of 6-5 g, of pure sodium cyanate in 50 ml. of warm water. Allow to stand for a few hours until crystallisation is complete. Filter with suction on a Buchner funnel, and wash with a little cold water. Dry in the steam... 

Hydrazine sulphate reacts with sodium cyanate in the presence of sodium carbonate to give semicarbazide, which remains in solution ... 

For example, 5,6-acenaphthenedicarboximide (44) can be prepared in 84% yield by the reaction of acenaphthene with excess sodium cyanate in anhydrous HF (78). The intermediate can be oxidized to the tetracarboxyhc acid. 

Benzyl chloride reacts with alkaH hydrogen sulfides, sulfides, and polysulfides to yield benzenethiol, dibenzyl sulfide, and dibenzyl polysulfide, respectively. With sodium cyanate it forms benzyl isocyanate (20). 

Molten sodium cyanide reacts with strong oxidizing agents such as nitrates and chlorates with explosive violence. In aqueous solution, sodium cyanide is oxidized to sodium cyanate [917-61 -3] by oxidizing agents such as potassium permanganate or hypochlorous acid. The reaction with chlorine in alkaline solution is the basis for the treatment of industrial cyanide waste Hquors (45) ... 

The hydroxyl derivative of X-CN is cyanic acid HO-CN it cannot be prepared pure due to rapid decomposition but it is probably present to the extent of about 3% when its tautomer, isocyanic acid (HNCO) is prepared from sodium cyanate and HCI. HNCO rapidly trimerizes to cyanuric acid (Fig. 8.25) from which it can be regenerated by pyrolysis. It is a fairly strong acid (Ka 1.2 x 10 at 0°) freezing at —86.8° and boiling at 23.5°C. Thermolysis of urea is an alternative route to HNCO and (HNCO)3 the reverse reaction, involving the isomerization of ammonium cyanate, is the clas.sic synthesis of urea by F. Wohler (1828) ... 

Dioxotetrahydro-l,3-oxazine derivatives (24) can be obtained by reacting jS-hydroxy acids with sodium cyanate to form a urethane derivative (23) followed by the action of thionyl chloride. ... 

C2H2ClNa02 3926-62-3) see Betaine hydrate sodium 2-(4-chlorophenoxy3-2-methylpropionate (C H,oClNaO, 7314-47-8) see Ronifibrate sodium cyanate... 

Isocyanic acid from sodium cyanate Schering Plough Res. Inst. Giusto (1994)... 

Aluminum hydroxychloride is used as a plugging agent [1394]. A weak-base activator such as sodium cyanate with an activator aid can establish delayed gelation. 

If excess acid is present, considerable foaming may occur on addition of sodium cyanate. 

A solution of 14.8 g. (0.20 mole) of Z-butyl alcohol in 125 ml. of benzene (Note 1) is placed in a 500-ml. three-necked flask equipped with a stirrer, a thermometer, and an addition funnel, and 26.0 g. (0.40 mole) of sodium cyanate (Note 2) is added. The suspension is stirred as slowly as possible (ca. 120 r.p.m. Note 3) while 48.0 g. (31.2 ml., 0.42 mole) of trifluoroacetic acid is added dropwise at a rapid rate. The temperature slowly rises to about 37° after three-quarters of the trifluoroacetic acid has been added (ca. 7 minutes). At this point (Note 4) the mixture is cooled to 33-35° by brief immersion in an ice-water bath, then the addition is continued. When the addition of the acid is completed (10-12 minutes total time), the temperature slowly... 

A" 0-Butenolide, 46, 22 /-Butyl alcohol, in synthesis of phenyl /-butyl ether, 45, 89 reaction with sodium cyanate and trifluoroacetic acid, 48, 32 /-Butyl azidoacctatc, 46, 47 hydrogenation of, 45, 47 /-Butyl carbamate, 48,32 /-Butyl chloroacetate, reaction with sodium azide, 45, 47 /ra S-4-/-BuTYI,CYCLOHEXANOL, 47,16... 

Sodium cyanate, reaction with <-butyl alcohol and trifluoroacetic acid, 48,32... 

Sodium cyanate cannot be replaced by other cyanates (potassium, ammonium, etc.), for the yields are then drastically lowered. 

The carbamates of tertiary acetylenic alcohols have also been made by reaction of these alcohols with sodium cyanate in tri-fluoroacetic acid.9 The yields by this procedure are significantly lower than those obtained by the present modification, which is essentially that described by Loev and Kormendy.5... 

Sodium compounds, 22 760-761, 762 as soap bar additives, 22 744 Sodium cyanamide, 8 184 Sodium cyanate, 8 184 Sodium cyanide, 8 183-184 analysis, 8 190 economic aspects, 8 189 health and safety factors, 8 190-191 manufacture, 8 187-189 properties, 8 184-187, 185t silver extraction via, 22 638, 646-647 uses, 8 191... 

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