| 摘要 |
Process for the activation of a supported acid catalyst by the transformation of Lewis acid-type sites deposited on the solid support into activated acid sites in an acidic non-oxidizing medium.The catalyst is submitted to an activation phase in a medium containing a halo-hydric acid (or precursor) in the presence of a hydrocarbon (or derivative), preferably paraffinic, at a temperature greater than 20 deg C (preferably 100 - 250 deg C) and a pressure of 10<5> - 50/*10<6> Pa for a time sufficient for transformation into activated acid sites (Bronstedt sites). Also claimed, are catalysts obtained by this process and their use in acid-catalysed reactions. Preferably 4 - 8C (more preferably 5 - 6C) hydrocarbon, or halogenated derivative, is used in the process. The Lewis sites comprise deposited metallic halides (Cl or Br) such as those of Al, B or Ga, or Zr (more preferably Al) or their mixtures. The ratio of halide to hydrocarbon is greater than 0.001 (preferably 0.005). The halo-hydric acid is contacted with the catalyst after adsorption of the hydrocarbon on the catalyst. The acid or precursor is introduced into the activation medium continuously or discontinuously. The time for the passage of the hydrocarbon charge over the catalyst is sufficient for at least 0.5% wt. of chlorine relative to the wt. of catalyst to pass across the catalyst bed. |
