ABSTRACT
HCN is a major chemical intermediate, first for the refining of ores and later for production of adiponitrile, a precursor of nylon. Following the research of Andrussow in the 1930s, HCN has been produced industrially mostly by reacting CH4, NH3, and O2 over Pt-Rh gauzes in what is now called the Andrussow process. A related process using only CH4 and NH3 is called the Degussa process. The yield of HCN in the Andrussow process is not as good as NO from NH3 oxidation, and this causes loss of expensive NH3 and problems in separating unreacted NH3 from HCN. The reaction is also quite dangerous because the fuels are flammable and explosive under some conditions, and the product is of course highly toxic. It has been known for many years that gauze catalysts activate over the first hours or days of operation and that they then deactivate over periods of weeks to months.
