(624e) Synthesis of Egg-Shell AuPd@SiO2 Catalysts for Liquid Phase Hydrogenation Reaction of Chloronitrobenzen to Chloaniline

Egg-shell catalyst is extensively used in industry for pore-diffusion controlled reaction. If the shell thickness is small enough, one can increase the space velocity, therefore the yield will increase in the same size reactor. The catalysts can be used in various reactions in industry, such as vinyl acetate production, etc. If metals are on the skin of the spherical beads, the pore diffusion will not be important. It is needed to develop a technique to prepare egg shell catalyst with 5 mm silica bead.

In this study, egg-shell Pd-Au were supported on spherical SiO₂ with 5 mm size. Using special technique, one was able to prepare a very thin shell. The catalysts were characterized by OM, TEM, HRTEM, and XPS. The catalyst was tested for liquid phase p-chloronitrobenzene hydrogenation reaction at 298 K, 0.55 MPa H₂ pressure in a Carberry reactor. The catalyst was very active under pore-diffusion controlled regime if the shell thickness was very thin.