Silver cyanamide

Methylisourea hydrochloride has been prepared by the action of hydrogen chloride on a suspension of silver cyanamide 2 or a solution of cyanamide3-4 in methanol,3 and by the action of dimethyl sulfate on urea at 112°.6 The free base is obtained by treating the salt with powdered potassium hydroxide in a water-ether mixture 3 or with sodium methoxide in methanol.0... 

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, colorless crystals, m.p. 40°, is readily soluble in water, alcohol, and ether. An aqueous solution of cyanamide gives a black precipitate of copper cyanamide with ammoniacal copper sulfate solution, and a yellow precipitate of silver cyanamide with ammoniacal silver nitrate. The precipitates are almost unique among the compounds of copper and silver in the respect that they are insoluble in ammonia water. 

This substance forms salts with acids, and was first isolated in the form of its nitrate. The nitrate is not detonated by shock but undergoes a rapid decomposition with the production of light when it is heated. The picrate and the perchlorate explode violently from heat and from shock. Guanyl azide is not decomposed by boiling water. On hydrolysis with strong alkali, it yields the alkali metal salt of hydrazoic acid. It is hydrolyzed by am-moniacal silver nitrate in the cold with the formation of silver azide which remains in solution and of silver cyanamide which appears as a yellow precipitate. By treatment with acids or weak bases it is converted into 5-aminotetrazole. 

Silver Cyanamide. See under Cyanamide and Derivatives in Vol 3, C581-L, plus the following addnl material ... 

Silicon, higher chlorides of, 42 Silicon tetrabromide, 38, 40 Silicon tetrachloride, 44 Silicopropane, octachloro, 44 Silicotungstic acid, 129 analysis, 131 ether complex, 131 Silver, metallic, 4 Silver chloride, reduction of, 3 Silver cyanamide, 98 Silver residues, purification of, 2 Sodium amalgam, 10 Sodium amide, 74 Sodium azide, purification of, 79 Sodium azidodithiocarbonate, 82 Sodium butoxide, 88 Sodium hypochlorite (solution), 90 Sodium iodate, 168 Sodium metaperiodate, 170 Sodium paraperiodate, chlorine method, 169 persulfate method, 170 Strontium amalgam, 11 Sulfur hexafluoride, 121 Sulfuryl chloride, 114... 

AgCl Silver chloride, 1 3 AgClOs Silver chlorate, 2 4 AgF Silver(I) fluoride, 4 136 AgF2 Silver (II) fluoride, 3 176 Agl Silver iodide, 2 6 AgO Silver (II) oxide, 4 12 Ag2CN2 Silver cyanamide, 1 98 Ag2P03F Silver monofluorophos-phate, 3 109... 

CN2Ag2 Silver cyanamide, 1 98 CN2H2 Cyanamide, 3 39, 41 CNa=CNa Disodium acetylide, 2 79, 80... 

Silver Cyanamide, As.,CN , is reported to decomp with expl violence in the temp range 330-50°. The proposed reaction mechanism is a 2-step, process forming AgCN, Ag N in the first step, followed by decompn of AgCN to Ag (CN)2 in the second step. The addn of metallic Ag, NaCl or CaF, moderated the reaction to measurable velocities of varying degrees (Ref... 

Reaction of gaseous silyl iodide 1 with silver cyanamide affords the disilylcarbodiimides 2 as colorless liquids stable at room temperature. ... 

Trialkyl- and alkoxysilyl halides react similarly with silver cyanamide or cyanamide and triethylamine. Also, PhsSiBr reacts with silver cyanamide to give bis(triphenylsilyl)-carbodiimide. Similarly, disilyl chlorides, MesSiSiCR, R )C13 react with silver cyanamide... 

Likewise, pentavalent P-disubstituted carbodiimides 13 are obtained in the reaction of R2P(X)C1 (X = O, S) with silver cyanamide. ... 

Cyclic oligomers of dimesylgennylcarbodiimide, (Mes2GeNCN) , where n = 3 and 4 are synthesized from dimesylchlorogermanium with silver cyanamide in the presence of tri-ethylamine or using lithium cyanamide. ... 

Silver cyanamide reacts with trimethylstannyl chloride 6 in refluxing benzene to give bis(trimethylstannyl)carbodiimide7. ... 

Other reactions of aminoguanidine with nitrous acid Cyanamide salts Silver cyanamide Nitrocyanamide salts Nitrophenol salts Lead picrate Lead styphenate Lead stypheratc manufacture... 

Indirect routes232 can be employed to synthesize JV,JV-bis(TMS)-carbodiimide (458) (a) by applying silver imidazole to 7V,jV-bis(TMS)-thiourea (457) (equation 213), (b) by reaction of Me3SiCl with silver cyanamide (459) (equation 214), (c) by reaction of Me3SiCl with hydrogen cyanamide (460) in the presence of a tertiary amine (equation 215) and (d) from cyanogen bromide (461) and hexamethyldisilazane (405) (equation 216). 

Cyanamide, CN.NH2, is a crystalline, hygroscopic solid, which polymerizes readily. Like other compounds in which the amido group is in combination with a negative radical, metallic derivatives may be formed by the replacement of the hydrogen atoms. Silver cyanamide, CH.NAg2, is a yellow amorphous substance which, unlike most silver salts, is insoluble in ammonia. 

Figure 25. Silver cyanamide crystal irradiated with uranium fission fragments (neutron flux density of 7.2 X 10 neutrons/cm ). At each bright area material has been decomposed by a fragment the dark areas are aggregated silver [119,120].

Agl Silver iodide, 2 6 Ag2CN2 Silver cyanamide, 1 98 [A1(C204)3]K3-3H20 Potassium tri-oxalatoaluminate, 1 36... 

CNCl Cyanogen chloride, 2 90, 93 (CN)2Ni Nickel cyanide, 2 228 CN2Ag2 Silver cyanamide, 1 98... 

One kilogram of the concentrated solution is transferred to an evaporating dish and while still warm (about 40°) is treated with 70 to 80 g. of concentrated aqueous ammonia to bring the concentration of the latter to about 2 per cent. The temperature of the solution is then raised as rapidly as possible on a steam bath. Heating is continued for 15 to 20 minutes until the cyanamide has been converted completely into dicyanodiamide, as shown by the nonformation of the characteristic yellow precipitate of silver cyanamide when an ammoniacal silver nitrate solution is added to a test portion. The solution is cooled and the solid product separated by filtration and dried at 100°. In a typical experiment there was obtained from 1 kg. of a 25 per cent solution 260 g. of dicyanodiamide (m.p. 206 to 208°) containing 0.46 per cent water by analysis. The yield is practically quantitative. 

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