Castner-Kellner process (sodium cyanide)

Castner-Kellner process (after Hamilton Castner and Karl Kellner ) describes an older process in the chemical industry for the production of sodium cyanide . It was developed by Castner and independently of Kellner around 1890 and implemented from the mid-1890s. A similar method comes from George Beilby from the same time. At that time, sodium cyanide was particularly needed for gold mining.

Sodium and charcoal are heated together, ammonia is added and reacts with sodium to form sodium amide according to the formula:

${\displaystyle \mathrm {2\ Na\ +\ 2\ NH_{3}\rightarrow \ 2\ NaNH_{2}\ +\ H_{2}} }$

Sodium amide changes into sodium cyanamide with coal at 873 K (600 ° C) :

${\displaystyle \mathrm {2\ NaNH_{2}\ +\ C\ \rightarrow \ Na_{2}N_{2}C\ +\ 2\ H_{2}} }$

At 1073 K (800 ° C) sodium cyanide is formed by further reaction of the sodium cyanamide with coal:

${\displaystyle \mathrm {Na_{2}N_{2}C\ +\ C\ \rightarrow \ 2\ NaCN} }$

Individual evidence

1. ^ Holleman, Wiberg, Textbook of Inorganic Chemistry, De Gruyter, 102nd edition 2007, p. 912