Cyanamide, calcium salt

CYANAMIDE, CALCIUM SALT (156-62-7) Combustible solid. Dust or powder forms explosive mixture with air. Contact with water, steam causes decomposition, forming acetylene gas, ammonia, and calcium hydrogen cyanamide. Violent reaction with strong oxidizers, fluorine, strong acids. Incompatible with barium peroxide, boric acid, dry hydrogen, hydrogen peroxide. Contact with all solvents tested also causes decomposition. 

Cyanamide, calcium salt Cyanamide, dimethyl-Cyanic acid, potassium salt Cyanide ion Cyanide radical... 

Synonyms Calcium carbimide Calcium cyanamid CCC Cyanamide, calcium Cyanamide, calcium salt (1 1)... 

A convenient way of obtaining secondary amines without contamination by primary or tertiary amines involves treatment of alkyl halides with the sodium or calcium salt of cyanamide NH2—CN to give disubstituted cyanamides, which are then hydrolyzed and decarboxylated to secondary amines. Good yields are obtained when the reaction is carried out under phase-transfer conditions. The R group may be primary, secondary, allylic, or benzylic. 1, co-Dihalides give cyclic secondary amines. 

Essentially, all primary skin irritants include acids, alkalis, metals, salts, and solvents. Among organic acids one may include acetic acid, acrylic acid, carbolic acid, chloroacetic acid, formic acid, lactic acid, oxalic acid, and salicylic acid. Among inorganic acids one may list arsenious acid, chromic acid, hydrochloric acid, hydrofluoric acid, nitric acid, phosphoric acid, and sulfuric acid. Alkalis include butylamines, ethylamines, ethanolamines, methylamines, propylamines, and triethanolamine. One also may include ammonium carbonate, ammonium hydroxide, calcium carbonate, calcium cyanamide, calcium hydroxide, calcium oxide, potassium carbonate, potassium hydroxide, sodium carbonate (soda ash), sodium hydroxide (caustic soda), and sodium silicate. 

Folina (Astra-Simes) Folinemic (Firma as calcium saIt)-comb. Lederfolin (Cyanamid as calcium salt)... 

Cyanamide, H2N =N , is a crystalline solid, mp 45 °C, prepared by hydrolysis of its calcium salt, CaNCN, under mild conditions (e.g. aqueous CO2) in order to avoid further hydrolysis of cyanamide. Calcium cyanamide is made on a large industrial scale by a high-temperature reaction of calcium carbide with molecular nitrogen (equation 18). The cyanamide... 

Cyanamide, H2N Ce=N, is obtained in the form of its calcium salt by the high-temperature reaction between calcium carbide and nitrogen. This reaction is... 

Bleach (chloride of lime) Bromine Butyl acetate Butyl phthalate Butyric acid Calcium carbide Calcium cyanamide Calcium hypochlorite Calcium nitrate Calcium potassium ferrocyan-ide (double salt)... 

Calcium ions are necessary for the growth of plants, and several calcium salts are used as fertilizers, e.g., calcium nitrate [Ca(N03)2] and calcium cyanamide (CaCN2)-... 

In the first step, calcium carbide is treated with nitrogen at about 1000°C to give calcium cyanamide. A suspension of calcium cyanamide in water is then treated with dilute sulphuric acid or carbon dioxide to form calcium sulphate or carbonate and cyanamide. The calcium salt is filtered off and the aqueous... 

Cyanamide can be made from the commercial calcium salt by hydrolysis, followed with H2SO4 ... 

Plants can also be pests that need to be controlled, particulady noxious weeds infesting food crops. Prior to 1900, inorganic compounds such as sulfuric acid, copper nitrate, sodium nitrate, ammonium sulfate, and potassium salts were used to selectively control mustards and other broadleaved weeds in cereal grains. By the early 1900s, Kainite and calcium cyanamid were also used in monocotyledenous crops, as well as iron sulfate, copper sulfate, and sodium arsenate. Prom 1915 to 1925, acid arsenical sprays, carbon bisulfate, sodium chlorate, and others were introduced for weed control use. Total or nonselective herbicides kill all vegetation, whereas selective compounds control weeds without adversely affecting the growth of the crop (see Herbicides). 

Preparation. Hexagonal boron nitride can be prepared by heating boric oxide with ammonia, or by heating boric oxide, boric acid, or its salts with ammonium chloride, alkaU cyanides, or calcium cyanamide at atmospheric pressure. Elemental nitrogen does not react with boric oxide even in the presence of carbon, though it does react with elemental boron at high temperatures. Boron nitride obtained from the reaction of boron trichloride or boron trifluoride with ammonia is easily purified. 

Benzeneamine, N-hydroxy-N-nitroso,ammonium salt Nitrilotrlacetic acid 4,4 -Thiodianiline Ethyl acrylate Butyl acrylate Ethyleneimine (Aziridine) p-Nrtrosodiphenylamine Calcium cyanamide Hydrazine Aldrin... 

Guanidines have been prepared by the reaction between an amine, or an amine salt, and a host of other reagents, such as a thiourea in the presence of lead or mercuric oxide [83, 157, 158], carbodi-imides [140, 174, 175],calcium cyanamide [176, 177], isonitrile dichlorides [178—180], chloroformamidines [181], dialkyl imidocarbonates [182], orthocarbonate esters [183], trichloro-methanesulphenyl chloride [184], and nitro- or nitroso-guanidines [185-188]. Substituted ureas can furnish guanidines, either by treatment with amines and phosphorus oxychloride [189], or by reaction with phenylisocyanate [190] or phosgene [191]. 

Chretien and Woringer [34] described the preparation of silver cyanamide from calcium cyanamide by the action of silver nitrate and also described its explosive properties. Montagu-Pollock [35] described a method for growing large crystals of the salt from its aqueous solution in the presence of ammonium nitrate, ammonia and a surface active agent. Bowden and Montagu-Pollock [36] and Montagu-Pollock [35] studied the slow decomposition of the crystals when heated at temperatures from 150 to 360°C. The course of decomposition was studied by electron microscope. 

Cyanamide pigments are produced from industrial-grade calcium cyanamide which is first dissolved. Sulfide and phosphide impurities are precipitated as iron or lead salts [5.127]—[5.132] or oxidized [5.133] [5.135] and filtered off together with graphite impurities. The pure calcium cyanamide is reacted in an aqueous medium with soluble lead or zinc salts or with a slurry of lead oxide or zinc oxide [5.127], [5.129], [5.133], [5.136]—[5.138]. The pigments are filtered, washed, dried, and ground. Zinc cyanamide [5.139] and pure lead cyanamide are not explosive. An explosion reported during the production of lead cyanamide was caused by contamination with small amounts of acid or nitrates [5.140],... 

Cyanamide is also acted upon directly by ammonium salts in aqueous and non-aqueous solutions.17-20 Since it is of decided advantage to avoid the isolation of pure cyanamide, methods have been developed in which aqueous solutions of cyanamide are prepared from calcium cyanamide and are then permitted to react with ammonium salts. However, guanidine nitrate may also be prepared directly from commercial calcium cyanamide by the action of ammonium nitrate. This reaction takes place readily in the fused state, in concentrated aqueous solution,21 or by direct admixture of solid ammonium nitrate with calcium cyanamide and subsequent heating to 100°C.22 The latter procedure is to be preferred, since better yields are obtainable and the hazard of fusion with ammonium nitrate is obviated. The directions given for procedure B require the use of a fairly good grade of unoiled calcium cyanamide containing approximately 65 per cent CaNCN. 

According to Goekel,22 this reaction takes place in the following manner Dry ammonium nitrate reacts with calcium hydroxide present in the crude calcium cyanamide to give calcium nitrate, water, and ammonia. The ammonia and water do not escape but are absorbed by the calcium nitrate to give a mixture of hydrated and ammonated salt and also by the ammonium nitrate which is ammono-deliquescent (Diver s solution). These substances melt below 100°C. and provide a solvent in which the reaction between calcium cyanamide and ammonium nitrate may take place. 

Gold powder, 4 14, 15 Graham s salt, 3 88, 104 Guanidonium nitrate, 1 94 from calcium cyanamide, 1 97 from dicyanodiamide, 1 96... 

The reader is already familiar with the weakly basic properties of ammonia. The commercial preparations of this base, both from the elements and from hydrolysis of calcium cyanamide, have already been noted. For preparation of small quantities of ammonia in the laboratory, an ammonium salt, either dry or in solution, may be heated with base. 

Zinc cyanamide is produced on an industrial scale from pure calcium cyanamide in an aqueous medium with zinc salts or a slurry of zinc oxide [5.56]. The pigment has, until now, not reached the importance of lead cyanamide for application in mirror coatings. 

---