Methods of making alkenyl alkanoates

Abstract

The present invention addresses at least four different aspects relating to catalyst structure, methods of making those catalysts and methods of using those catalysts for making alkenyl alkanoates. Separately or together in combination, the various aspects of the invention are directed at improving the production of alkenyl alkanoates and VA in particular, including reduction of by-products and improved production efficiency. A first aspect of the present invention pertains to a unique palladium/gold catalyst or pre-catalyst (optionally calcined) that includes rhodium or another metal. A second aspect pertains to a palladium/gold catalyst or pre-catalyst that is based on a layered support material where one layer of the support material is substantially free of catalytic components. A third aspect pertains to a palladium/gold catalyst or pre-catalyst on a zirconia containing support material. A fourth aspect pertains to a palladium/gold catalyst or pre-catalyst that is produced from substantially chloride free catalytic components.

1 . A method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates, comprising: 
 contacting palladium and rhodium precursors to a support material; and    reducing the palladium and rhodium precursors by contacting a reducing environment to the support material.    
     
     
         2 . The method of  claim 1 , further comprising contacting a gold precursor to a support material and reducing the gold precursor.  
     
     
         3 . The method of  claim 1 , calcining the contacted support material in a non-reducing atmosphere.  
     
     
         4 . The method of  claim 1 , wherein the contacting step comprises impregnating gold precursor onto the support material after impregnating with palladium and rhodium precursors.  
     
     
         5 . The method of  claim 1 , wherein the contacting step comprises co-impregnating palladium and rhodium precursors, followed by impregnating with the gold precursor.  
     
     
         6 . The method of  claim 1 , wherein the contacting step comprises co-impregnating palladium, rhodium and gold precursors.  
     
     
         7 . The method of  claim 1 , wherein the calcining step occurs after the impregnation of the gold precursor.  
     
     
         8 . The method of  claim 1 , wherein the calcining step occurs before the impregnation of the gold precursor.  
     
     
         9 . The method of  claim 1 , further comprising at least one fixing step of fixing at least one of the precursors with a fixing agent.  
     
     
         10 . The method of  claim 1 , wherein the order of method comprises: 
 impregnating the support material with an aqueous solution of a water soluble palladium precursor;    impregnating the support material with an aqueous solution of a water soluble rhodium precursor;    fixing the palladium and rhodium precursors with a fixing agent;    calcining the fixed palladium and rhodium precursors;    impregnating the support material with an aqueous solution of a water soluble gold precursor; and    reducing the palladium, gold and rhodium precursors.    
     
     
         11 . The method of  claim 1 , wherein the order of method comprises: 
 impregnating the support material with an aqueous solution of a water soluble palladium precursor;    impregnating the support material with an aqueous solution of a water soluble rhodium precursor;    fixing the palladium and rhodium precursors with a fixing agent;    impregnating the support material with an aqueous solution of a water soluble gold precursor; and    calcining the fixed palladium, rhodium and gold precursors; and    reducing the palladium, gold and rhodium precursors.    
     
     
         12 . The method of  claim 1 , wherein the order of method comprises: 
 co-impregnating the support material with an aqueous solution of water soluble palladium and rhodium precursors;    fixing the palladium and rhodium precursors with a fixing agent;    calcining the fixed palladium and rhodium precursors;    impregnating the support material with an aqueous solution of a water soluble gold precursor; and    reducing the palladium, gold and rhodium precursors.    
     
     
         13 . The method of  claim 1 , wherein the order of method comprises: 
 co-impregnating the support material with an aqueous solution of water soluble palladium and rhodium precursors;    fixing the palladium and rhodium precursors with a fixing agent;    calcining the fixed palladium and rhodium precursors;    reducing the palladium and rhodium precursors; and    impregnating the support material with an aqueous solution of a water soluble gold precursor.    
     
     
         14 . The method of  claim 1 , wherein the order of method comprises: 
 co-impregnating the support material with an aqueous solution of water soluble palladium and rhodium precursors;    fixing the palladium and rhodium precursors with a fixing agent;    impregnating the support material with an aqueous solution of a water soluble gold precursor; and    calcining the fixed palladium, rhodium and gold precursors; and    reducing the palladium, gold and rhodium precursors.    
     
     
         15 . The method of  claim 1 , wherein the order of method comprises: 
 co-impregnating the support material with an aqueous solution of water soluble palladium, rhodium and gold precursors;    calcining the palladium, rhodium and gold precursors; and    reducing the palladium, rhodium and gold precursors.    
     
     
         16 . The method of  claim 1 , further comprising contacting potassium acetate to the support material in an amount of between about 10 and 70 grams per liter of catalyst.  
     
     
         17 . The method of  claim 1 , wherein the contacting step comprises contacting between about 1 to about 10 grams of palladium, 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.  
     
     
         18 . A method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates, comprising: 
 layering a first support material on to a second support material to produce a layered support material, wherein catalytic components of palladium, gold or combinations thereof are contained in the first support material of the layered support material.    
     
     
         19 . The method of  claim 18 , further comprising contacting the catalytic components to the first support material before the layering step.  
     
     
         20 . The method of  claim 18 , further comprising contacting the catalytic components to the first support material after the layering step.  
     
     
         21 . The method of  claim 18 , wherein the catalytic components comprise palladium, gold, or combinations thereof.  
     
     
         22 . The method of  claim 18 , further comprising contacting palladium to the first support material before the layering step and contacting gold to the first support material after the layering step.  
     
     
         23 . The method of  claim 18 , further comprising contacting gold to the first support material before the layering step and contacting palladium to the first support material after the layering step.  
     
     
         24 . The method of  claim 18 , wherein the second support material is an inner layer and is substantially free of catalytic components.  
     
     
         25 . The method of  claim 18 , further comprising contacting potassium acetate to the support material before the layering step.  
     
     
         26 . The method of  claim 18 , further comprising contacting potassium acetate to the support material after the layering step.  
     
     
         27 . The method of  claim 18 , further comprising impregnating the first support material with palladium, calcining the first support material, impregnating the first support material with gold.  
     
     
         28 . The method of  claim 18 , further comprising impregnating the first support material with palladium, layering the first support material on to the second support material, calcining the layered support material, and impregnating the first support material with gold.  
     
     
         29 . The method of  claim 18 , further comprising calcining the layered support material before contacting the catalytic components to the layered support material.  
     
     
         30 . The method of  claim 18 , wherein the second support material is non-porous.  
     
     
         31 . The method of  claim 18 , wherein the first support material is selected from the group consisting of alumina, silica/alumina, zeolites, non-zeolitic molecular sieves, titania, zirconia, niobia, silica, bentonite, clays, and combinations thereof.  
     
     
         32 . The method of  claim 18 , wherein the second support material is selected from the group consisting of alumina, silicon carbide, zirconia, titania, steatite, niobia, silica, bentonite, clays, metals, glasses, quartz, silicon nitride, alumina-silica, pumice, non-zeolitic molecular sieves and combinations thereof.  
     
     
         33 . The method of  claim 18 , wherein the layering step comprises contacting a bonding agent to the first or second support material to promote adhesion between the materials.  
     
     
         34 . The method of  claim 18 , wherein the bonding agent is selected from organic and inorganic bonding agents.  
     
     
         35 . The method of  claim 18 , wherein the bonding agent is a zirconia bonding agent.  
     
     
         36 . A method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates, comprising: 
 contacting palladium and gold precursors to a zirconia containing support material; and    reducing at least the palladium precursor by contacting a reducing environment to the zirconia containing support material.    
     
     
         37 . The method of  claim 36 , further comprising calcining the contacted zirconia containing support material in a non-reducing atmosphere before the reducing step.  
     
     
         38 . The method of  claim 36 , wherein the contacting step comprises impregnating the zirconia containing support material with palladium and gold precursors.  
     
     
         39 . The method of  claim 36 , wherein the impregnating step comprises sequentially impregnating palladium and gold precursors onto the zirconia containing support material.  
     
     
         40 . The method of  claim 36 , wherein the calcining step occurs before the impregnation of the gold precursor.  
     
     
         41 . The method of  claim 36 , wherein the reducing step occurs before the impregnating of the gold precursor.  
     
     
         42 . The method of claims  36 , wherein the impregnating step comprises co-impregnating palladium and gold precursors.  
     
     
         43 . The method of  claim 36 , wherein the impregnating step comprises impregnating the zirconia containing support material with water soluble, substantially chloride free precursor solutions.  
     
     
         44 . The method of  claim 36 , wherein the impregnating step comprises impregnating the zirconia containing support material with chloride containing precursor solutions and following by a fixing step comprising fixing with a fixing agent.  
     
     
         45 . The method of  claim 36 , wherein the calcining step comprises heating the contacted zirconia containing support material at a temperature between about 200° C. and about 700° C.  
     
     
         46 . The method of  claim 36 , further comprising contacting potassium acetate to the zirconia containing support material in an amount of between about 10 and 70 grams per liter of catalyst.  
     
     
         47 . The method of claims  36 , wherein the contacting step comprises contacting between about 1 to about 10 grams of palladium, 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.  
     
     
         48 . A method of producing a catalyst or pre-catalyst suitable for assisting in the production of alkenyl alkanoates, comprising: 
 contacting at least one catalytic precursor solution comprising palladium and gold to a support material wherein the at least one catalytic precursor solution is an aqueous solution that is substantially free of chloride; and    reducing the palladium or gold by contacting a reducing environment to the support material.    
     
     
         49 . The method of  claim 48 , wherein the palladium catalytic precursor solution comprises Pd(NH 3 ) 2 (NO 2 ) 2 , Pd(NH 3 ) 4 (OH) 2 , Pd(NH 3 ) 4 (NO 3 ) 2 , Pd(NO 3 ) 2 , Pd(NH 3 ) 4 (OAc) 2 , Pd(NH 3 ) 2 (OAc) 2 , Pd(OAc) 2  in KOH or NMe 4 OH or NaOH, Pd(NH 3 ) 4 (HCO 3 ) 2 , palladium oxalate or combinations thereof.  
     
     
         50 . The method of  claim 48 , wherein the gold catalytic precursor solution comprises KAuO 2 , NaAuO 2 , NMe 4 AuO 2 , Au(OAc) 3  in KOH or NMe 4 OH, HAu(NO 3 ) 4  in nitric acid or combinations thereof.  
     
     
         51 . The method of  claim 48 , wherein the support material comprises silica, alumina, silica-alumina, titania, zirconia, niobia, silicates, aluminosilicates, titanates, spinel, silicon carbide, silicon nitride, carbon, steatite, bentonite, clays, metals, glasses, quartz, pumice, zeolites, non-zeolitic molecular sieves, or combinations thereof.  
     
     
         52 . The method of  claim 48 , wherein the support material comprises a layered support material.  
     
     
         53 . The method of  claim 48 , wherein the layered support material comprises an inner layer and an outer layer, wherein the inner layer is substantially free of palladium and gold.  
     
     
         54 . The method of  claim 48 , wherein the contacting step comprises contacting between about 1 to about 10 grams of palladium, and about 0.5 to about 10 grams of gold per liter of catalyst to the support material, with the amount of gold being from about 10 to about 125 wt % based on the weight of palladium.  
     
     
         55 . The method of  claim 48 , wherein the contacting step comprises separately impregnating palladium and gold on to the support material.  
     
     
         56 . The method of  claim 48 , further comprising a calcining step in a non-reducing atmosphere after impregnation of palladium and before impregnation of gold.  
     
     
         57 . The method of  claim 48 , wherein the contacting step comprises co-impregnating palladium and gold on to the support material.  
     
     
         58 . The method of  claim 48 , further comprising a calcining step in a non-reducing atmosphere before the reducing step.  
     
     
         59 . The method of  claim 48 , further comprising contacting potassium acetate to the support material in an amount of between about 10 and 70 grams per liter of catalyst.