Cuprous cyanide, with

Cupric cyanide, Cu(CN)2.—The cyanide is obtained as a brownish-yellow precipitate by the interaction of solutions of potassium cyanide and cupric sulphate, but it is very unstable, decomposing at ordinary temperatures into cupric cuprous cyanide, Cu[Cu.(CN)2]2,5H20, with evolution of cyanogen. On heating, it is converted into cuprous cyanide. With hydrazine cyanide it unites to form a monohydrazinate, Cu(CN)2,N2H4, yellow needles insoluble in water, m.p. 160° to 162° C.7... 

Lithium cuproferrocyanide,2 Li2Cu2Fe(CN)6, is obtained by boiling cuprous cyanide with a solution of lithium ferrocyanide containing lithium sulphite, hydrogen gas being simultaneously bubbled through the solution. It crystallises in colourless, hexagonal prisms. 

Potassium cuproferrocyanide, K2Cu2Fe(CN)6, is prepared 1 by boiling cuprous cyanide with a solution of potassium ferrocyanide containing a little potassium sulphite or by boiling cuprous chloride or potassium cuprous cyanide with potassium ferrocyanide solution. When rapidly cooled, the solution yields colourless cubes, but the crystals are liable to undergo partial oxidation, turning yellow or brown in colour. 

Potassium cupriferrocyanide, K2CuFe(CN)6, results2 on boiling cuprous cyanide with an excess of potassium ferncyanide solution —... 

For the most part, vinyl halides are unreactive however, a few have been converted to vinyl-type cyanides under conditions employed for aromatic halogen compounds. Thus, sym-diiodoethylene has been converted by cuprous cyanide with an amine promoter to fumaronitrile (74%). The halogen atom in certain triarylvinyl bromides has also been replaced by the cyano group under these conditions. ... 

The reaction of cuprous cyanide with an aryl halide to produce a nitrile gives an intermediate complex of the nitrile with cuprous haUde. Friedman and Shechter found that the nitrile can be liberated from the complex very easily by addition of... 

Cuprous cyanide solution. The most satisfactory method is to dissolve the cuprous cyanide (1 mol) in a solution of technical sodium cyanide (2 5-2-6 mols in 600 ml. of water). If it is desired to avoid the preparation of solid cuprous cyanide, the following procedure may be adopted. Cuprous chloride, prepared from 125 g. of copper sulphate crystals as described under 1 above, is suspended in 200 ml. of water contained in a 1-litre round-bottomed flask, which is fitted with a mechanical stirrer. A solution of 65 g. of technical sodium cyanide (96-98 per cent.) in 100 ml. of water is added and the mixture is stirred. The cuprous chloride passes into solution with considerable evolution of heat. As the cuprous cyanide is usually emplo3 ed in some modification of the diazo reaction, it is usual to cool the resulting solution in ice. 

Allyl cyanide. Into a 1 5 litre three-necked flask (1), provided with a mercury-sealed stirrer and two long double surface condensers, place 293 g. (210 ml.) of freshly-distilled allyl bromide, b.p. 70-71° (Section III, 35) and 226 g. of dry cuprous cyanide (Section 11,50,3, Method 1), Remove the mercury-sealed stirrer and replace it by a tightly fitting... 

Method 1. a-Naphthonitrile. Place 80 g. (54 ml.) of redistilled a-bromonaphthalene (Section IV.20), 43 g. of dry powdered cuprous cyanide (Section II,50,J) and 36 g. (37 ml.) of dry pure pyridine (1) (Section 11,47.22) in a 250 ml. round-bottomed flask fitted with a ground-in reflux condenser carrying a calcium chloride (or cotton wool) guard tube, and heat the mixture in a metal bath at 215-225° for... 

By heating halogenated benzenes or naphthalenes with cuprous cyanide, for example, a-naphthonitrile from a-bromonaphthalene and cuprous cyanide (Section IV,163). 

The patended method of preparation of the blue dye (120) [19187-01 -0] (81) involves treating the analogous dibromo substituted azo dye with cuprous cyanide in dimethylformamide or A-methylpyrrohdinone at 50°C to effect replacement of the two bromo substituents by cyano groups. 

The greenish-blue dye (117) (82) is prepared in a similar fashion, replacing bromo with cyano by using cuprous cyanide, pyridine, and 2-methoxyethanol as solvent at 85°C. 

Chloro-l,2-benzisothiazole reacts with sodium cyanide to give a mixture containing mainly o-cyanophenyl thiocyanate with some di-(o-cyanophenyl) disulfide. An 80% yield of the latter was obtained using cuprous cyanide in DMF (73SST(2)556). 

Terephthalic acid has been obtained from a great many /)-disubstituted derivatives of benzene or cyclohexane by oxidation with permanganate, chromic acid, or nitric acid. The following routes appear to have preparative value from />-toluic acid, />-methylacetophenone,2 or dihydro-/)-tolualdehyde by oxidation with permanganate from f>-cymene by oxidation with sodium dichromate and sulfuric acid from />-dibromobenzene or from /i-chloro- or -bromobenzoic acid by heating at 250° with potassium and cuprous cyanides and from />-dibromo-benzene, butyllithium, and carbon dioxide. ... 

Cuprous cyanide [544-92-3] M 89.6, m 474°. Wash thoroughly with boiling H2O, then with EtOH. Dry at 100° to a fine soft powder. [J Chem Soc 79 1943.]... 

Another process using butadiene as the starting material was developed by Esso. This involved the reaction of butadiene with iodine and cuprous cyanide to give the cuprous iodide complex of dehydroadiponitrile. This is further reacted with HCN to give a high yield of dehydroadiponitrile and regeneration of the iodine and cuprous iodide. 

Methoxythiophene and 3-cyanothiophene have been prepared from 3-bromothiophene by means of a cupric oxide-catalyzed Williamson synthesis and by reaction with cuprous cyanide in quinoline, respectively. 

Halogeno compounds have been prepared by direct halogena-tion or by Sandmeyer reaction on 4-aminoisothiazoles. As expected from general considerations, a halogen atom in the 4-position is less reactive than one in the 5-position, but nitriles are obtained in good yield with cuprous cyanide at elevated temperatures. With butyllithium, lithiation occurs exclusively in the 5-position, and no evidence of halogen displacement has been obtained. ... 

A. Preparation of Cuprous Cyanide. (Note i)—In a 6-1. round-bottom flask fitted with a stopper carrying a mechanical stirrer, a separatory funnel, and a gas exit tube leading to a good hood (Note 2), is placed a solution of 650 g. (2.6 moles) of crystallized copper sulfate in 4 1. of water. The flask is surrounded by an oil bath and heated to about 8o°. The stirrer is started and a solution of 255 g. (5.2 moles) of sodium cyanide (Note 3) in 650 cc. of water is added from the separatory funnel over a period of about one-half hour. Then the mixture is boiled until no more cyanogen gas is evolved. This requires about five to ten minutes. 

The cuprous cyanide, which begins to separate as a light tan precipitate as soon as any of the cyanide solution is added, is allowed to settle and the solution is decanted. The precipitate is filtered, then washed with water (r 1.) and finally with alcohol (500 cc.) and ether (300 cc.). After drying at no0 for about thirty-six hours, the product weighs 200-210 g. (85-90 per cent of the theoretical amount). 

The cuprous cyanide must be dry, as small amounts of moisture reduce the yield considerably (about 15 per cent). With some samples of technical cuprous cyanide a larger amount must be used. 

Allyl cyanide has been found in oil of mustard 1 and has been prepared from allyl chloride and potassium cyanide,2 allyl bromide and potassium cyanide,3 allyl iodide and potassium cyanide4 and silver cyanide.5 The method described in the procedure is essentially that of Bruylants, who has shown that the yields are much better when dry cuprous cyanide is treated with allyl bromide.6... 

The reaction of diazo compounds with amines is similar to 10-15. The acidity of amines is not great enough for the reaction to proceed without a catalyst, but BF3, which converts the amine to the F3B-NHR2 complex, enables the reaction to take place. Cuprous cyanide can also be used as a catalyst. The most common substrate is diazomethane, in which case this is a method for the methylation of amines. Ammonia has been used as the amine but, as in the case of 10-44, mixtures of primary, secondary, and tertiary amines are obtained. Primary aliphatic amines give mixtures of secondary and tertiary amines. Secondary amines give successful alkylation. Primary aromatic amines also give the reaction, but diaryl or arylalkyl-amines react very poorly. 

The reaction between aryl halides and cuprous cyanide is called the Rosenmund-von Braun reactionP Reactivity is in the order I > Br > Cl > F, indicating that the SnAt mechanism does not apply.Other cyanides (e.g., KCN and NaCN), do not react with aryl halides, even activated ones. However, alkali cyanides do convert aryl halides to nitrilesin dipolar aprotic solvents in the presence of Pd(II) salts or copper or nickel complexes. A nickel complex also catalyzes the reaction between aryl triflates and KCN to give aryl nitriles. Aromatic ethers ArOR have been photochemically converted to ArCN. 

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