Genesis of durable catalyst for selective hydrodechlorination of CCl4 to CHCl3 Original Research Article

Hydrodechlorination (HDC) of CCl4 to CHCl3 is an economically and environmentally attractive alternative for CCl4 disposal. Commercially available 0.3 wt% egg-shell Pt/Al2O3 pellet catalysts from several catalyst vendors were evaluated for CCl4 HDC. In all cases, the catalysts were rapidly deactivated during reaction at 90°C; the CCl4 conversion dropped from 90% to 2% within an hour. A remarkably durable catalyst was obtained by treating the as-received commercial Pt/Al2O3 catalyst with a solution of NH4Cl. The treated catalyst showed excellent CCl4 HDC performance for over 2000 h without deactivation. Treatment with NH4Cl resulted in an increased Pt particle size, which is crucial for a Pt catalyst to resist HCl poisoning.