Decomposition of Thiocyanates by Oxidizing Agents

Abstract

Reaction of aq. NH₄SCN with 22 N H₂SO₄ was studied in order to estimate the yield of HCN from thiocyanate-fixers under strong acid conditions.
Main gaseous products were identified to be HCN, CS, and COS by GC-MS. The amounts of HCN were measured by Pyridine-Pyrazolone method (JIS K 0102) and the maximum concentrations were ca. 1.2×10^-2 mol/l and 1.4×10^-2 mol/l for 2 mol/l and 4 mol/l NH₄SCN respectively.
Yellow solid was precipitated in the reaction and the molecular formula was determined to be C₂H₂N₂S₃ by elementary analysis.