Modified support materials for catalysts

Abstract

The present invention relates to a method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates. The method includes contacting a modifier precursor to a support material to form a modified support material. One or more catalytic component precursors (palladium or gold) may be contacted to the modified support material. The atomic ratio of gold to palladium is preferably in the range of about 0.3 to about 0.90. The support materials with the catalytic component may then be reduced using a reducing environment. A composition for catalyzing the production of an alkenyl alkanoates including a modified support material with palladium and gold is also included within the invention. Catalysts of the present invention may be used to produce alkenyl alkanoates in general and vinyl acetate in particular and are useful to produce low EA/VA ratios while maintaining or improving CO 2 selectivity.

1 . A method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates, comprising:
 contacting a modifier precursor to a support material;   contacting at least one catalytic component precursor to the modified support material; and   reducing the catalytic component precursor by contacting a reducing environment to the support material.   
     
     
         2 . The method of  claim 1  further comprising calcining the modified support material in a non-reducing atmosphere prior to contacting the at least one catalytic component precursor to the modified support material. 
     
     
         3 . The method of  claim 2  wherein the modifier precursor comprises barium, magnesium, cerium, potassium, calcium, niobium, tantalum, titanium, yttrium, strontium, zirconium, lanthanum, praseodymium, vanadium, molybdenum, rubidium, or binary combinations thereof. 
     
     
         4 . The method of  claim 3  wherein the modifier precursor comprises niobium, titanium, magnesium, zirconium or combinations thereof. 
     
     
         5 . The method of  claim 4  wherein the modifier precursor comprises niobium, titanium, magnesium or combinations thereof. 
     
     
         6 . The method of  claim 2  wherein the modifier precursor comprises a chloride, a nitrate, an oxalate, a lactate or combinations thereof. 
     
     
         7 . The method of  claim 2  wherein the support material comprises zirconia. 
     
     
         8 . The method of  claim 20  wherein the support material comprises titano-silicate or zircono silicate. 
     
     
         9 . The method of  claim 2  wherein the support material is a layered support material. 
     
     
         10 . The method of  claim 1  wherein the first contacting step comprises impregnating the support material with an aqueous modifier precursor solution. 
     
     
         11 . The method of  claim 10  wherein the first contacting step comprises contacting the support material with between about 0.1 wt % and about 4.0 wt % of modifier based on the weight of support material. 
     
     
         12 . The method of  claim 1  wherein the second contacting step comprises impregnating the support material with an aqueous catalytic component precursor solution. 
     
     
         13 . The method of  claim 3  wherein the modifier calcining step comprises calcining at a temperature between about 300° C. and about 700° C. 
     
     
         14 . The method of  claim 1  further comprising calcining after contacting the support material with the catalytic component precursor. 
     
     
         15 . The method of  claim 1  wherein the catalytic component precursor comprises gold, palladium, or a combination thereof. 
     
     
         16 . The method of  claim 15  wherein the atomic ratio of gold to palladium is between about 0.1 and about 1.25. 
     
     
         17 . The method of  claim 16  wherein atomic ratio of gold to palladium is between about 0.3 and about 0.90. 
     
     
         18 . The method of  claim 1  further comprising contacting the catalyst or pre-catalyst with an activating agent. 
     
     
         19 . The method of  claim 18  further comprising contacting alkali metal acetate to the support material in an amount of between about 10 and 70 grams per liter of catalyst. 
     
     
         20 . The method of  claim 15  wherein the catalytic component contacting step comprises contacting between about 1 to about 10 grams of palladium per liter of catalyst, and about 0.5 to about 10 grams of gold per liter of catalyst, with the amount of gold being from about 10 to about 125 wt % based on the weight of palladium. 
     
     
         21 . A composition for catalyzing the production of an alkenyl alkanoates, comprising:
 a modified support material with at least palladium and gold contacted thereon to form a catalyst or pre-catalyst, wherein the modified support material is formed from one or more modifier precursors.