Catalyst carrier based on silica gel

Abstract

The present invention relates to spherical beads comprising at least one metal and/or semimetal oxide, having a mean diameter in the range from 10 to 120 μm, a BET surface area in the range from 400 to 800 m 2 /g and a pore volume in the range from 0.3 to 3.0 cm 3 /g, wherein the diameter of a given bead at any one point of said bead deviates by less than 10% from the average diameter of said bead and the surface of said bead is substantially smooth, and also to a process for producing these spherical beads, to a particulate catalyst comprising the spherical beads and to the use of the spherical beads as catalysts or catalyst carriers.

1 - 10 . (canceled) 
     
     
         11 . Spherical beads comprising at least one metal and/or semimetal oxide, having a mean diameter in the range from 10 to 120 μm, a BET surface area in the range from 400 to 800 m 2 /g and a pore volume in the range from 0.3 to 3.0 cm 3 /g, wherein the diameter of a given bead at any one point of said bead deviates by less than 10% from the average diameter of said bead and the surface of said bead is substantially smooth. 
     
     
         12 . The beads according to  claim 11  wherein the at least one metal and/or semimetal oxide is selected from the group consisting of SiO 2 , Al 2 O 3 , TiO 2 , MgO and mixtures thereof. 
     
     
         13 . The beads according to  claim 11 , consisting of SiO 2  to an extent of at least 96% by weight. 
     
     
         14 . The beads according to  claim 11  wherein the at least one metal and/or semimetal oxide is substantially amorphous. 
     
     
         15 . The beads according to  claim 11  wherein the BET surface area is in the range from 500 to 600 m 2 /g. 
     
     
         16 . The beads according to  claim 11  wherein the pore volume is in the range from 1.5 to 2.5 cm 3 /g. 
     
     
         17 . A process for producing spherical beads according to  claim 11 , comprising the steps:
 (A) providing a mixture comprising at least one at least partially water-miscible organic solvent, water and at least one precursor compound of the at least one metal and/or semimetal oxide as mixture A,   (B) providing a mixture comprising at least one at least partially water-miscible organic solvent, water and at least one acid as mixture B,   (C) combining the mixtures A and B and reacting the at least one precursor compound of the at least one metal and/or semimetal oxide with said at least one acid to obtain a mixture C comprising an aqueous phase comprising the spherical beads and an organic phase,   (D) separating the organic phase from the mixture C obtained in step C to obtain an aqueous phase comprising the spherical beads,   (E) optionally treating the spherical beads obtained in step (D) with at least one acid, and   (F) drying the spherical beads obtained in step (D) or (E).   
     
     
         18 . The process according to  claim 17  wherein the at least one precursor compound of the at least one metal and/or semimetal oxide is selected from the group consisting of alkali metal silicates, alkaline earth metal silicates, colloidal silica sols and mixtures thereof. 
     
     
         19 . The process according to  claim 17  wherein the at least one precursor compound of the at least one metal and/or semimetal oxide is selected from the group consisting of potassium silicate, sodium silicate, alkaline earth metal silicates, colloidal silica sols and mixtures thereof. 
     
     
         20 . A particulate catalyst comprising the spherical beads according to  claim 11  and at least one catalytically active metal. 
     
     
         21 . A method of using spherical beads according to  claim 11  as catalysts or catalyst carriers. 
     
     
         22 . A catalyst or a catalyst carrier which comprises the spherical beads according to  claim 11 .