Selective hydrogen cyanide synthesis from CFC12 (CCl₂F₂) and ammonia over metal catalysts supported on LaF₃ and activated charcoal

The applicability of supports such as LaF₃, activated charcoal and Cr₂O₃ to the new reaction, CCl₂F₂ + 5 3NH₃→HCN + 2HCl + 2HF + 1 3N₂ was examined and it was found that TiO₂ itself reacted with CFC12 to give carbon monoxide and carbon dioxide even at 673 K in addition to hydrogen cyanide formation. LaF₃ did not react with CFC (chlorofluorocarbon) even at 823 K so that it could be considered suitable for use as a catalyst support. Au(1 wt.-%)/LaF₃ and Pt(1 wt.-%)/LaF₃ were effective for hydrogen cyanide formation and hydrogen cyanide selectivity reached 77-78% at 823 K. Activated charcoal was also suitable for use as a catalyst support and hydrogen cyanide was formed selectively (72-84%) over Rh(1 wt.-%)/AC and Pd(1 wt.-%)/AlF₃/AC catalysts at 823 K.