Process for the selective hydrogenation of phenylacetylene

Abstract

A process for the reduction of a phenylacetylene contaminant in the presence of a styrene monomer. A styrene monomer stream containing a minor amount of phenylacetylene is supplied to a hydrogenation reactor. A hydrogenation gas comprising hydrogen is also supplied to the hydrogenation reactor. The styrene monomer stream and the hydrogen are bought into contact with a catalyst bed containing a catalyst comprising a reduced copper compound on a theta alumina support. The hydrogenation reactor is operated at a temperature of at least 60° C. and a pressure of at least 30 psig to hydrogenate phenylacetylene to styrene. A product is recovered from the hydrogenation reactor having a substantially reduced phenylacetylene content and an enhanced styrene content. The hydrogenation gas comprises a mixture of nitrogen and hydrogen.

1 - 20 . (canceled)  
     
     
         21 . A process for the reduction of phenylacetylene in the presence of a styrene monomer comprising: 
 supplying a styrene monomer stream comprising an amount of phenylacetylene to a hydrogenation reactor;    supplying a hydrogenating gas comprising hydrogen to the hydrogenation reactor;    within the hydrogenation reactor, flowing the styrene monomer stream and the hydrogen into contact with a catalyst bed comprising a copper based hydrogenation catalyst comprising metallic copper on a theta alumina support;    operating the reactor at a temperature of at least 60° C. and a pressure of at least 30 psig to hydrogenate phenylacetylene to produce styrene; and    recovering a product from the hydrogenation reactor having a reduced phenylacetylene content and an enhanced styrene content.    
     
     
         22 . The method of  claim 21 , wherein the selective hydrogenation of phenylacetylene in the reactor is effective to convert at 60% of the phenylacetylene in the reactor input stream to styrene.  
     
     
         23 . The method of  claim 21 , wherein the hydrogenation reactor is operated at a pressure of from about 45 psig to about 150 psig.  
     
     
         24 . The method of  claim 21 , wherein the hydrogenation reactor is operated at a temperature of from about 60° C. to about 80° C.  
     
     
         25 . The method of  claim 21 , wherein the hydrogenation component comprises a mixture of hydrogen and nitrogen.  
     
     
         26 . The method of  claim 25 , wherein a molar ratio of nitrogen to hydrogen in the mixture is from about 0.2:1 to about 2.0:1.  
     
     
         27 . The method of  claim 21 , wherein the hydrogenation gas comprises a mixture of nitrogen, hydrogen and carbon monoxide.  
     
     
         28 . The method of  claim 27 , wherein the carbon monoxide is present in an amount of from about 1 mol. % to about 5 mol. % of the mixture.  
     
     
         29 . The method of  claim 21 , wherein the styrene monomer stream contains less than 1 vol. % of phenylacetylene.  
     
     
         30 . The method of  claim 29 , wherein the styrene monomer stream supplied to the reactor comprises from about 40 ppm to about 150 ppm of phenylacetylene.  
     
     
         31 . The method of  claim 29 , wherein the product recovered from the hydrogenation reactor comprises about 10 ppm or less phenylacetylene.  
     
     
         32 . The method of  claim 29 , wherein the selective hydrogenation of phenylacetylene in the reactor is effective to convert at least 70% of the phenylacetylene in the styrene monomer stream to styrene.  
     
     
         33 . The method of  claim 21 , wherein the copper based hydrogenation catalyst comprises from about 5 wt. % to about 25 wt. % copper.