Extruded catalyst based on silica/alumina gel, and process for preparing it

Abstract

The preparation is disclosed of an extruded catalyst based on a silica/alumina gel, which catalyst is particularly active in acid-catalyzed reactions, such as the oligomerization of light olefins, e.g., propylene.

1 . Catalyst consisting of: 
 an inert binding agent, and    a catalytically active portion, constituted by a silica/alumina gel, amorphous at X rays, with SiO 2 /AL 2 O 3  being in a molar ratio comprised within the range of from 30:1 to 500:1, having a total pore volume comprised within the range of from 0.3 to 0.6 mL/g, and substantially free from pores having a Longer average diameter than 30 Angstrom,    characterized in that: 
 the inert binding agent is constituted by alumina grades belonging to the class of bohemite or of pseudobohemite.  
   
     
     
         2 . Catalyst according to  claim 1 , characterized in that bohemite or pseudobohemite have an average diameter shorter than 50 microns, and are present in a ratio to silica/alumina gel comprised within the range of from 0.2 to 2.5 by weight.  
     
     
         3 . Process for preparing the catalyst according to claims from  1  to  2 , characterized in that the active portion is mixed with the inert phase, in the presence of a thickener containing a mineral or organic acid in an amount comprised within the range of from 0.5 to 8 g of acid per 100 g of inert binding agent, until a homogeneous paste is obtained which is subsequently extruded, yielding cylindrical bodies of catalyst which are eventually submitted to: 
 ageing at a temperature comprised within the range of from 10 to 40° C.;  
 drying at a temperature comprised within the range of from 100 to 120° C.;  
 calcination in air at a temperature comprised within the range of from 500 to 600° C.  
 
     
     
         4 . Use of the catalyst according to claims from  1  to  2  in acid-catalyzed reaction.  
     
     
         5 . Use of the catalyst according to claims from  1  to  2  in the oligomerization of light olefins.  
     
     
         6 . Use of the catalyst according to claims from  1  to  2  in propylene oligomerization.