The Manufacture of Sodium Cyanide (Notes courtesy Bert Tucker) Sodium cyanide can be manufactured in a number of ways. Two relatively simple methods are described in the scientific literature. The first involves the use of the readily available dye, Prussian Blue (Iron III Ferro cyanide). A second uses the common swimming pool chlorine stabiliser, cyanuric acid. In the first process the Prussian Blue is first converted to sodium ferrocyanide. This is done by allowing it to react with caustic soda in water. Iron oxide is precipitated and sodium ferro cyanide obtained. This sodium ferrocyanide (Yellow Prussate of Soda) is then converted to sodium cyanide by allowing it to react with concentrated sulphuric acid. Fig7.1: Forge reduces sodium cyanate with carbon
The very toxic HCN produced is passed into caustic soda to form the desired salt. There is considerable information available on this process but it was abandoned after initial experiments, considering it too dangerous for the inexperienced home chemist - some of whom may be readers of this book. A more suitable method of safe, small-scale home manufacture of sodium cyanide involves the two stage conversion of the common swimming pool chemical cyanuric acid. Cyanide 95 The first step is carried out by heating powdered cyanuric acid with sodium carbonate. Sodium carbonate is obtained directly as washing soda (or by converting sodium bicarbonate, baking soda). In the second stage, the sodium cyanate produced is reduced to sodium cyanide by heating it with powdered charcoal in a covered crucible (Fig 7.1). It is important that this stage is undertaken outside. In this process, carbon monoxide is given off. The resultant glassy mass is cooled, crushed and filtered with water to remove the soluble sodium cyanide from the remaining insoluble carbon (Fig 7.2). Careful drying produces solid sodium cyanide powder. As with all home manufacture there is a need for great care in carrying out this process. Contaminated items need to be disposed of carefully after traces of cyanide are removed. This is best achieved using chlorine bleach to oxidise any unwanted cyanide and to prevent it contaminating the equipment. The product also needs to be tested by analytic means to determine its concentration and purity. Quantitative tests are available and Exit offers such a service for supporters. Further information that details the manufacturing process can be found in most university and public libraries. The Peaceful Pill Handbook