Activated metathesis catalysts

Abstract

Process for preparing a supported catalyst (catalyst C) comprising a support (support S) and an active component (activator A), wherein a) a catalyst precursor is prepared by applying an activator customary for the catalysis of metathesis reactions (activator precursor) to a customary support (step a), b) the catalyst precursor prepared in step a) is brought into contact with a hydrocarbon compound at from −20 to 550° C. (step b) and c) the catalyst precursor prepared in step b) is heated at from 410 to 850° C. in an inert gas atmosphere (step c).

We claim:  
     
         1 . A process for preparing a supported catalyst (catalyst C) comprising a support (support S) and an active component (activator A), wherein 
 a) a catalyst precursor is prepared by applying an activator customary for the catalysis of metathesis reactions (activator precursor) to a customary support (step a),    b) the catalyst precursor prepared in step a) is brought into contact with a hydrocarbon compound at from −20 to 550° C. (step b) and    c) the catalyst precursor prepared in step b) is heated at from 410 to 850° C. in an inert gas atmosphere (step c).    
     
     
         2 . A process as claimed in  claim 1 , wherein the support (S) is selected from among oxides, phosphates, silicates, carbides, borides and nitrides of main group elements and elements of transition groups VI and II and mixtures of the abovementioned compounds.  
     
     
         3 . A process as claimed in either of the preceding claims, wherein the support (S) is selected from the group consisting of Al 2 O 3 , aluminosilicates, Ga 2 O 3 , SiO 2 , GeO 2 , TiO 2 , ZrO 2 , SnO 2  and mixtures of the abovementioned compounds.  
     
     
         4 . A process as claimed in any of the preceding claims, wherein the activator precursor comprises compounds containing elements of transition groups V, VI and VII.  
     
     
         5 . A process as claimed in  claim 4 , wherein the compounds of elements of transition groups V, VI and VII are selected from the group consisting of sulfides, oxides, nitrides, carbides, oxycarbides, carbonyls, organic complexes, halides, acids, polyacids, heteropolyacids and salts of the acids, polyacids and heteropolyacids.  
     
     
         6 . A process as claimed in any of the preceding claims, wherein the activator precursor comprises compounds selected from the group consisting of rhenium, tungsten and molybdenum compounds.  
     
     
         7 . A process as claimed in any of the preceding claims, wherein the activator precursor comprises compounds selected from the group consisting of molybdenum oxides, tungsten carbides and tungsten oxides.  
     
     
         8 . A process as claimed in any of the preceding claims, wherein the activator precursor comprises compounds selected from the group consisting of compounds of metals of transition groups V, VI and VII and a promoter selected from the group consisting of cobalt, alkali metal and alkaline earth metal compounds.  
     
     
         9 . A process as claimed in any of the preceding claims, wherein step (a) is carried out by impregnating the support (S) with a solution of the activator precursor and subsequently drying it and, if desired, calcining it.  
     
     
         10 . A process as claimed in any of the preceding claims, wherein the hydrocarbon compound used in step (b) is selected from the group consisting of C 1 -C 20 -alkanes, -cycloalkanes, -olefins, -cycloolefins, -alkynes, -cycloalkynes, aromatics and mixtures of the abovementioned compounds.  
     
     
         11 . A process as claimed in any of the preceding claims, wherein the inert gas used in step (c) is selected from the group consisting of nitrogen, carbon dioxide and noble gases and mixtures thereof.  
     
     
         12 . A catalyst (C) obtainable by a process as claimed in any of  claims 1  to  11 .  
     
     
         13 . A catalyst (C) as claimed in  claim 12  comprising from 0.1 to 30% by weight of WO 3  in tetragonal form.  
     
     
         14 . A catalyst (C) as claimed in  claim 13 , wherein the support S consists essentially of SiO 2 .  
     
     
         15 . A process for preparing unsaturated compounds by metathesis using a catalyst (C).  
     
     
         16 . A process as claimed in  claim 15 , wherein 3-hexene and ethylene are prepared by bringing 1-butene into contact with a catalyst (C) at from 50 to 500° C.  
     
     
         17 . A process as claimed in  claim 11 , wherein propene is prepared by bringing a mixture of 2-butenes with ethylene or 1-butene into contact with a catalyst (C) at from 50 to 500° C.