Method of preparing phenylacetic acid

Abstract

A method of preparing phenylacetic acid comprising phase-transfer carboxylation of benzyl sodium in the presence of a salt catalyst.

1 . A method of preparing phenylacetic acid comprising phase-transfer carboxylation of benzyl sodium in the presence of a salt catalyst.  
   
   
       2 . The method of method of  claim 1 , comprising: 
 combining chlorobenzene and sodium in a solution to produce a mixture;    adding the catalyst;    adding dry ice to the mixture;    maintaining the mixture until removal of the dry ice in gaseous form;    treating the remaining residue with hydrochloric acid; and    separating the phenylacetic acid from the remaining solution including the catalyst.    
   
   
       3 . The method of  claim 1 , wherein the catalyst comprises a tetra-ethyl-ammonium-halide.  
   
   
       4 . The method of  claim 3 , wherein the catalyst is selected from the group consisting of tetra-ethyl-ammonium-chloride and tetra-ethyl-ammonium-bromide.  
   
   
       5 . The method of  claim 2 , wherein combining chlorobenzene and sodium in a solution comprises combining chlorobenzene and sodium in a solution of toluene/benzene.  
   
   
       6 . The method of  claim 2 , wherein separating the phenylacetic acid from the solution including the catalyst comprises continuous separation of the phenylacetic acid and the catalyst.  
   
   
       7 . The method of  claim 2 , further comprising recovering the catalyst in solution for reuse.  
   
   
       8 . The method of  claim 2 , further comprising crystallizing the phenylacetic acid from water.  
   
   
       9 . A method of preparing phenylacetic acid comprising: 
 combining benzyl-sodium with a tetra-ethyl-ammonium-halide catalyst;    adding dry ice to the mixture;    maintaining the mixture until removal of the dry ice in gaseous form;    treating a residue with hydrochloric acid; and    separating the phenylacetic acid from the remaining solution including the catalyst.    
   
   
       10 . The method of  claim 9 , wherein the a tetra-ethyl-ammonium-halide catalyst is selected from the group consisting of a tetra-ethyl-ammonium-chloride and a tetra-ethyl-ammonium-bromide.  
   
   
       11 . The method of  claim 9 , further comprising: 
 recovering the catalyst in the remaining solution; and    reusing the recovered catalyst during a subsequent combination of chlorobenzene and sodium for preparation of phenylacetic acid.    
   
   
       12 . The method of  claim 9 , wherein adding dry ice to the mixture comprises adding crushed dry ice to the mixture.  
   
   
       13 . The method of  claim 9 , further comprising combining chlorobenzene with sodium in a toluene solution to produce the benzyl-sodium.  
   
   
       14 . The method of  claim 9 , wherein combining benzyl-sodium with a tetra-ethyl-ammonium-halide catalyst comprises adding the a tetra-ethyl-ammonium-halide catalyst with the benzyl-sodium in toluene under nitrogen at a temperature of in the range of approximately 25 to 27 degrees Celsius.  
   
   
       15 . The method of  claim 9 , further comprising stirring the mixture while slowly adding the dry ice.