Hydrogen cyanide process

A process for producing HCN which comprises bringing a mixture of gases containing CO and NH.sub.3 in a mol ratio of about 1:4 to about 1:6 and at a temperature of about 550.degree. C. to about 750.degree. C. and at a pressure of about 500 to about 650 psig into contact with a solid, water-insoluble catalyst containing alumina and silica as essential components and having a protonic acid strength of at least 15 meq/m.sup.2 .times.10.sup.4.

A process for producing HCN and recovering HCN in substantially pure form which comprises bringing a mixture of gases containing CO and NH.sub.3 at elevated temperatures and pressures into contact with a solid, water-insoluble catalyst having a protonic acid strength of at least 15 meq/m.sup.2 10.sup.4 to form a mixture of gases containing essentially HCN, H.sub.2 O, CO.sub.2, CO, NH.sub.3, H.sub.2, N.sub.2, and CH.sub.4, absorbing HCN, H.sub.2 O, and CO.sub.2 from said mixture in an absorption zone containing liquid NH.sub.3 to form a liquid mixture composed essentially of NH.sub.3, ammonium cyanide, H.sub.2 O and small amounts of ammonium carbamate, purging a portion of the gas mixture leaving the absorption zone thereby obtaining a substantially steady state content of H.sub.2, N.sub.2 and CH.sub.4, removing said liquid mixture from said adsorption zone and treating same with an acidic aqueous liquid, thereby causing HCN to be released as a gas, from the ammonium cyanide in said liquid mixture and recovering the HCN gas.