Metallic hydrogenation catalysts, production and use thereof

Abstract

The catalyst can be prepared by reduction of a precursor of a hydrogenation-active metal, which may be present on an oxidic support, by reaction with at least one compound of the formula (I) H n M(OR) 3-n   (I) where M is Ga or Al, R is CR′ 3 or SiR′ 3 where R′ is C 1-20 -alkyl, and n is 1 or 2, or dimers or oligomers thereof, wherein the crystallite size of the hydrogenation-active metal in the finished catalyst is from 5 to 30, preferably 5 to 15 nm.

1 . A catalyst which comprises a crystallite comprising reduced Ni on an oxidic support, which is prepared by reduction of a Ni-source on an oxidic support, selected from the group consisting of TiO 2 , ZrO 2  and mixtures thereof, by reaction of the Ni-source with at least one compound of the formula (I)  
         H n M(OR) 3-n   (I)  where    M is Ga or Al,    R is CR′ 3  or SiR′ 3  where R′ is C 1-20 -alkyl, and    n is 1 or 2,    or dimers or oligomers thereof; wherein said catalyst further comprises Ga or Al.    
     
     
         2 . A catalyst as claimed in  claim 1 , wherein the compound of the formula (I) is H 2 Al(OCR′ 3 ) where R′ is C 1-13 -alkyl or a dimer thereof.  
     
     
         3 . A catalyst as claimed in  claim 1 , wherein, in the reaction, the oxide and/or hydroxide of Ni is used in solid form and the compound of the formula (I) or the dimer or oligomer thereof is used in gaseous form.  
     
     
         4 . A catalyst as claimed in  claim 1 , wherein the crystallite comprising reduced Ni has a size of from 5 to 30 nm.  
     
     
         5 - 6 . (canceled)  
     
     
         7 . A process for preparing aromatic compounds containing amino groups by hydrogenation of corresponding aromatic compounds bearing nitro groups in the presence of a catalyst, as claimed in  claim 1 .  
     
     
         8 . (canceled)  
     
     
         9 . A catalyst as claimed in  claim 1 , wherein the crystallite comprising reduced Ni has a size of from 5 to 15 nm.  
     
     
         10 . A catalyst as claimed in  claim 1 , wherein M is Al, and said catalyst further comprises Al.  
     
     
         11 . A catalyst as claimed in  claim 1 , wherein R′ is methyl and n is 2.  
     
     
         12 . A catalyst as claimed in  claim 1 , wherein the Ni-source is nickel oxide.  
     
     
         13 . A catalyst as claimed in  claim 1 , wherein the reduction occurs at a temperature of from 20 to 600° C.  
     
     
         14 . A catalyst as claimed in  claim 1 , wherein the reduction occurs at a temperature of from 200 to 500° C.  
     
     
         15 . A catalyst as claimed in  claim 1 , wherein said catalyst comprises Ga or Al in an amorphous form.