| 摘要 |
Prepn. of catalysts based on mordenite contg. 0.5 wt.% Na, with molar ratio SiO2/Al2O3 of 10-100 and contg. Co, Ni, Ag and/or Pd comprises (A) incorporating the metal into Na mordenite with SiO2/Al2O3 ratio around 10; (B) removing most of the Na ions, and drying at 50-150 degrees C; (C) calcining at 300-700 degrees C in dry inert or oxidising gas contg. =1 vol.% steam, and (D) calcining at 250-700 degrees C in steam, or in inert or oxidising gas contg. >=3 vol. % steam. Used for catalytic conversion of aromatics, esp. dismutation reactions, e.g. conversion of toluene to benzene and xylene, or trans-alkylation reactions, e.g. prodn. of xylenes from toluene/trimethyl benzene mixts. Use of the moist calcination stage (D) gives catalysts with high activity and stability in use, and with improved selectivity. |
