Cyanogen chloride prepn. from hydrogen cyanide and chlorine - in aq. manganous chloride soln. for high yield and chlorine recovery

摘要

In prepn. of cyanogen chloride by (a) reacting HCN and Cl2 in an aq. medium to form CNCl and dissolved HCl and (b) recovering the CNCl, (a) is conducted in the presence of sufficient MnCl2 to minimise hydrolysis losses and prevent formation of NCl3. The process pref. also produces Cl2 by (c) reacting the HCl-MnCl2 soln. at elevated temp. with solid MnO2 in 1:4 molar ratio MnO2:HCl to form gaseous Cl2 and residual MnCl2 soln., (d) recovering Cl2 (e) reacting residual MnCl2 soln. with solid MnO2 and concn. HNO3 at elevated temp. with MnO2:MnCl2 1:1 and HNO3:MnCl2 4:1, forming gaseous Cl2 and acidic Mn(NO3)2 soln. and (f) recovering gaseous Cl2. High yields of CNCl, e.g. around 90% of overhead gases obtd. with low hydrolysis (0-0.8 for pref. concns.) and no NCl3 formation. Prod. HCl is sufficiently conc. for economic Cl2 recovery.