Polyoxometallate supported catalysts

Abstract

Disclosed are catalysts situated on a polyoxometallate supported. Also disclosed are methods of preparing these catalysts and processes for the conversion of alkanes to unsaturated organic compounds using these catalysts.

What is claimed is:  
     
         1 . A catalyst composition comprising a catalyst situated on a polyoxometallate support; wherein the polyoxometallate support has the formula 
       C a H (e−az) (X k M m−x M 1   x M 2   n O y ) −e   (I) wherein C is a cation selected from potassium, rubidium, cesium, magnesium, calcium, strontium, barium, transition metal, actinide metal, lanthanide metal, metal oxy ion, ammonium, tetraalkylammonium, pyridinium, quinolinium, protonated aromatic amines, protonated aliphatic amines or mixtures thereof; X is an element selected from Groups 3-16 elements; M=molybdenum, tungsten or a combination thereof; M 1 =vanadium; M 2  is a transition metal different from M and M 1 ; z=the charge on C; k=1 to 5; m=5 to 20; n=0 to 3; x=0 to 6; y=18 to 62; and e is the charge of the polyoxometallate anion; and    provided that the catalyst is not a heteropolyacid.    
     
     
         2 . The composition of  claim 1  wherein the catalyst is selected from the group comprising mixed metal oxides, vanadium phosphorus compounds and mixtures thereof.  
     
     
         3 . The composition of  claim 2  wherein the mixed metal oxide has the formula 
       A a′ M 3   m′ L l Z z′ O o   (II) 
       wherein A is selected from molybdenum, tungsten, iron, niobium, tantalum, zirconium, ruthenium, and mixtures thereof; M 3  is selected from vanadium, cerium, chromium, and mixtures thereof; L is selected from tellurium, bismuth, antimony, selenium, and mixtures thereof; Z is selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhenium, nickel, palladium, platinum, antimony, bismuth, boron, indium, cerium, and mixtures thereof; a′=0.25 to 0.98; m′=0.003 to 0.5; l=0.003 to 0.5; z′=0.003 to 0.5; and o is dependent on the oxidation state of the other elements.  
     
     
         4 . The composition of  claim 3  further comprising a heteropolyacid.  
     
     
         5 . The composition of  claim 2  wherein the vanadium phosphorus compound comprises vanadyl phosphite or vanadyl pyrophosphite.  
     
     
         6 . The composition of  claim 2  wherein the catalyst is present as a molecular precursor.  
     
     
         7 . The composition of  claim 1  wherein the polyoxometallate support comprises Cs 3 (PMo 12 O 40 ), Cs 4 (PMo 11 VO 40 ), Cs 5 (PMo 10 V 2 O 40 ), Cs 6 (PMo 9 V 3 O 40 ), Cs 3 (PW 12 O 40 ), Cs 4 (PW 11 O 40 ), Cs 5 (PW 10 V 2 O 40 ), Cs 6 (PW 9 V 3 O 40 ) or combinations thereof.  
     
     
         8 . A process for preparing a catalyst composition comprising a catalyst situated on a polyoxometallate support; wherein the polyoxometallate support has the formula 
       C a H (e−az) (X k M m−x M 1   x M 2   n O y ) −e   (I) 
       wherein C is a cation selected from potassium, rubidium, cesium, magnesium, calcium, strontium, barium, transition metal, actinide metal, lanthanide metal, metal oxy ion, ammonium, tetraalkylammonium, pyridinium, quinolinium, protonated aromatic amines, protonated aliphatic amines or mixtures thereof; X is an element selected from Groups 3-16; M is as defined above; M 1 =vanadium; M 2  is a transition metal different from M and M 1 ; z=the charge on C; k=1 to 5; m=5 to 20; n=0 to 3; x=0 to 6; y=18 to 62; and e is the charge of the polyoxometallate anion; including the step of admixing the catalyst with the polyoxometallate support; provided that the catalyst is not a heteropolyacid.  
     
     
         9 . The process of  claim 8  wherein the catalyst is selected from the group comprising mixed metal oxides, vanadium phosphorus compounds and mixtures thereof.  
     
     
         10 . The process of  claim 8  wherein the mixed metal oxide has the formula 
       A a′ M 3   m′ L l Z z′ O o   (I) 
       wherein A is selected from molybdenum, tungsten, iron, niobium, tantalum, zirconium, ruthenium, and mixtures thereof; M 3  is selected from vanadium, cerium, chromium, and mixtures thereof; L is selected from tellurium, bismuth, antimony, selenium, and mixtures thereof; Z is selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhenium, nickel, palladium, platinum, antimony, bismuth, boron, indium, cerium, and mixtures thereof; a′=0.25 to 0.98; m′=0.003 to 0.5; l=0.003 to 0.5; z′=0.003 to 0.5; and o is dependent on the oxidation state of the other elements.  
     
     
         11 . The process of  claim 10  further comprising a heteropolyacid.  
     
     
         12 . The process of  claim 9  wherein the vanadium phosphorus compound comprises vanadyl phosphite or vanadyl pyrophosphite.  
     
     
         13 . The process of  claim 9  wherein the catalyst is present as a molecular precursor.  
     
     
         14 . A process for preparing unsaturated organic compounds comprising the steps of contacting an alkane with an oxidizing agent and a catalyst composition including one or more mixed metal oxides, vanadium phosphorus compounds or mixtures thereof situated on a polyoxometallate support; wherein the mixed metal oxide has the formula 
       A a′ M 3   m′ L l Z z′ O o   (II) wherein A is selected from molybdenum, tungsten, iron, niobium, tantalum, zirconium, ruthenium, and mixtures thereof; M 3  is selected from vanadium, cerium, chromium, and mixtures thereof; L is selected from tellurium, bismuth, antimony, selenium, and mixtures thereof; Z is selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhenium, nickel, palladium, platinum, antimony, bismuth, boron, indium, cerium, and mixtures thereof; a′=0.25 to 0.98; m′=0.003 to 0.5; l=0.003 to 0.5; z′=0.003 to 0.5; o is dependent on the oxidation state of the other elements; and    wherein the polyoxometallate support has the formula   C a H (e−az) (X k M m−x M 1   x M 2   n O y ) −e   (II)   wherein C is a cation selected from potassium, rubidium, cesium, magnesium, calcium, strontium, barium, transition metal, actinide metal, lanthanide metal, metal oxy ion, ammonium, tetraalkylammonium, pyridinium, quinolinium, protonated aromatic amines, protonated aliphatic amines or mixtures thereof; X is an element selected from Groups 3-16 elements; M=molybdenum, tungsten or a combination thereof; M 1 =vanadium; M 2  is a transition metal different from M and M 1 ; z=the charge on C; k=1 to 5; m=5 to 20; n=0 to 3; x=0 to 6; y=18 to 62; and e is the charge of the polyoxometallate anion.    
     
     
         15 . The process of  claim 14  wherein the catalyst further comprises a heteropolyacid.  
     
     
         16 . The process of  claim 14  wherein the polyoxometallate support comprises Cs 3 (PMo 12 O 40 ), Cs 4 (PMo 11 VO 40 ), Cs 5 (PMo 10 V 2 O 40 ), Cs 6 (PMo 9 V 3 O 40 ), Cs 3 (PW 12 O 40 ), Cs 4 (PW 11 VO 40 ), Cs 5 (PW 10 V 2 O 40 ), Cs 6 (PW 9 V 3 O 40 ) or combinations thereof.  
     
     
         17 . The process of  claim 14  wherein the alkane comprises ethane, propane, n-butane, iso-butane, n-pentane, iso-pentane, cyclopentane, hexane, cyclohexane, heptane, octane, cyclooctane, decane, dodecane, tetradecane, hexadecane and mixtures thereof  
     
     
         18 . The process of  claim 14  wherein the unsaturated organic compound comprises unsaturated carboxylic acids, unsaturated aldehydes, unsaturated ketones, unsaturated anhydrides, alkenes and combinations thereof.  
     
     
         19 . The process of  claim 18  wherein the unsaturated organic compound comprises acrylic acid, methacrylic acid, maleic acid, acrolein, methacrolein, acrylonitrile, methacrylonitrile, propylene, isobutylene, butylene, butadiene, maleic anhydride, and combinations thereof.  
     
     
         20 . A process for preparing a mixed metal oxide catalyst of the formula 
       A a′ M 3   m′ L l Z z′ O o   (II) 
       wherein A is selected from molybdenum, tungsten, iron, niobium, tantalum, zirconium, ruthenium, and mixtures thereof; M 3  is selected from vanadium, cerium, chromium, and mixtures thereof; L is selected from tellurium, bismuth, antimony, selenium, and mixtures thereof; Z is selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhenium, nickel, palladium, platinum, antimony, bismuth, boron, indium, cerium, and mixtures thereof; a′=0.25 to 0.98; m′=0.003 to 0.5; l=0.003 to 0.5; z′=0.003 to 0.5; o is dependent on the oxidation state of the other elements; including the step of heating a mixed metal oxide molecular precursor at a temperature of at least 600° C. for a period of time sufficient to convert the precursor to the mixed metal oxide.