Cuprous Acetylide-Chloride

Cuprous Acetylide-Chloride, CjCuj+CuCl+HjO, dk violet pdr, deflagrates very weakly on heating in an open flame. Was prepd by passing acetylene through CuCl in 0.2N HCl Refs I)Beil 1,(104) 2)W.Manchot J.C. 

Note Some other cuprous acetylide-chloride comp ds (none of them seem to be expl) were described in Beil IJ910I and in the following Scandinavian papers ... 

Metallic Derivatives, (a) Cuprous Acetylide. CujCg. Prepare an ammoniacal solution of cuprous chloride by first adding dilute ammonia to 2-3 ml. of dilute copper sulphate solution until the initial precipitate just redissolves and a clear deep-blue solution is obtained now add an aqueous solution of hydroxylamine hydrochloride drop by drop with shaking until the solution becomes first green and then completely colourless, the cupric salt being thus reduced to the cuprous derivative. 

The only reaction which calls for comment here is the formation of red cuprous acetylide with an ammoniacal solution of cuprous chloride ... 

Cuprous acetylide was prepared by Berthelot [102] as early as 1866 by the action of acetylene on an ammonia solution of cuprous chloride. Cuprous acetylide takes the form of a russet or reddish-brown powder, insoluble in water and in the majority of organic solvents. 

Much research was necessary in order to establish the chemical composition of cuprous acetylide. Blochmann [103] and Scheiber and Reckleben [104] showed that the freshly precipitated and dried product has the approximate composition Cu2C2 H20. According to Keiser [105] drying this salt over sulphuric acid or calcium chloride (Scheiber and Reckleben [104]) gives an anhydrous product. 

Care should be taken that cuprous acetylide is not contaminated with cupric acetylide which may occur if the cuprous chloride used for the reaction contains cupric salt. This is of importance since cupric acetylide is unstable and explodes on heating even between 50 and 70°C. It is also more sensitive to impact and friction than cuprous acetylide. The pure cupric acetylide is black or brown. 

Silver acetylide, Ag2C2, is a white powder formed when acetylene is passed through an ammoniacal solution of silver chloride. It has even stronger explosive properties than cuprous acetylide due to its exceptionally large negative heat of formation —87.15 kcal/mole). Its ignition temperature is 200°C. It is of... 

The discovery of acetylene in 1836(or 1837) is attributed to Edmond Davy, but it was not until I860 that Berthelot definitely identified and named it(Ref 9, p 101 Ref 16, p 469). The compd obtained by Berthelot from cuprous acetylide was not pure because it contained some vinyl chloride. Acetylene was not produced commercially until Ca carbide was produced in the lab in 1899 by Morehead Willson, by heating a mixt of lime and coke in an electric furnace. They expected to prepare metallic calcium... 

Cuprous acetylide, of which only a very small quantity may be prepared safely at one time, is procured by bubbling acetylene into an ammoniacal solution of cuprous chloride. It precipitates as a brick-red powder. The powder is collected on a small paper filter and washed with water. About 0.1 gram of the material, still moist, is transferred to a small iron crucible—the rest of the cuprous acetylide ought to be destroyed by dissolving in dilute nitric acid—and the crucible is placed on a triangle over a small flame. As soon as the material has dried out, it explodes, with a loud report, causing a dent in the bottom of the crucible. 

The type a) expl sometimes with a report, spades and flashes to form black CuO. It could be fired by a drop of HNO,. The ex-plosibility of this type of acetylide is greater than thatof cuprous acetylide. This type includes most acetylides, formed from the more common cupric salts, such as die chloride, sulfate and nitrate, and those formed from copper org salts made alkaline with alkaliesother than ammonia, or also with ammonia, provided insufficient ammonia is present to retain all the Cu as a complex salt... 

Diacetylene or Butadiyne (called Diacetylen or Butadiin in Get), HCiC.C. CH raw 50,06 gas at RT having a pronounced odor, forms Ifts on cooling with liq air, fr p -36 bp 10° at 760mm press, d 0,7364 at 0°, nj 1,4386 at 0,87 can be prepd by the action of cupric chloride soln on cuprous acetylide, followed by treatment of the Cu diacety-lide,thus formed,with dil HCl and by action of excess alcoholic KOH at 150-60° on butadiene tecrabromide and by other methods (Refs 1 2 ... 

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