Andrussow process

The Andrussow process is the dominant industrial process for the production of hydrogen cyanide.^[1] It involves the reaction of methane, ammonia, and oxygen. The process is catalyzed by a platinum-rhodium alloy.^[2]

2 CH₄ + 2 NH₃ + 3 O₂ → 2 HCN + 6 H₂O

Diagram from 1931 showing the Andrussow process

Hydrogen cyanide is highly valued for the production or acrylonitrile and adiponitrile, as well as alkali metal salts such as potassium cyanide.^[1]

Process details

This reaction is very exothermic. The change of enthalpy of this reaction is equal to -481.06 kJ.^[3] The heat provided by the main reaction serves as a catalyst for other side reactions.

CH₄ + H₂O → CO + 3 H₂

2 CH₄ + 3 O₂ → 2 CO + 4 H₂O

4 NH₃ + 3 O₂ → 2 N₂ + 6 H₂O

These side reactions can be minimized by only short exposures to the catalyst of the order of 0.0003 s.^[4]

Historical articles

The process is based on a reaction that was discovered by Leonid Andrussow in 1927. In the following years he developed the process that is named after him. HCN is also produced in the BMA process.^[5][6]