| 摘要 |
Enhancing activity of a catalyst comprising 25-75 wt.% of a crystalline zeolite, having initial ion exchange capacity less than 0.7 meq/g, and 75-25 wt.% of an Al2O3 and/or Ga2O3 matrix comprises: (i) calcining at 200-600 deg.C for 1 min-48 h; (ii) saturating with dry BF3 vapour; and (iii) converting the zeolite in the catalyst to the H form. Catalyst is pref. satd. by contact with flowing BF3 (e.g. mixed with an inert gas) at 0-100 deg.C, esp. about ambient to 50 deg.C, using about 0.2-2 g BF3 per g zeolite. Immediately after saturation of the catalyst, as indicated by falling temp. the remaining BF3 should be purged out. The zeolite can then be converted to the H form by (i) contacting with water at 20-550 deg.C, (ii) contacting with anNH4 salt soln. (e.g. 1N NH4NO3) for 1-20 h at up to 100 deg.C, and finally (iii) calcination in air, N2 etc. at 200-600 deg.C for 1 min-48h. |
