Process and system for the electrochemical reduction of oxalic acid

Abstract

The present disclosure concerns a process and a system for the electrochemical reduction of oxalic acid to glyoxylic acid. The process involves withdrawing a portion of oxalic acid-depleted catholyte from the process and contacting it with a quantity of solid oxalic acid to provide a concentrated oxalic acid solution which is re-entered into the process.

1 - 10 . (canceled) 
     
     
         11 . A reaction system for carrying out the electrochemical reduction of oxalic acid to glyoxylic acid, said system comprising
 an electrochemical cell comprising a cathode compartment containing a cathode, an anode compartment containing an anode and an ion exchange membrane separating the anode compartment from the cathode compartment   a catholyte loop fluidly connecting the cathode compartment and a catholyte holding tank, said catholyte loop being configured for moving a liquid catholyte comprising an aqueous oxalic acid solution from the catholyte holding tank into the cathode compartment, over the surface of the cathode, and removing from the cathode compartment and returning to the catholyte holding tank an oxalic acid-depleted catholyte   an energy source configured for applying an electric potential difference between the cathode and the anode and to reduce oxalic acid in the cathode compartment to glyoxylic acid,   means for withdrawing a portion of an oxalic acid-depleted catholyte from the catholyte loop and/or from the catholyte holding tank   means for contacting the oxalic acid-depleted catholyte portion with a quantity of solid oxalic acid to provide a concentrated oxalic acid solution, and   means for providing at least a portion of the concentrated oxalic acid solution to the catholyte holding tank.   
     
     
         12 . The reaction system according to  claim 11 , wherein the means for contacting the oxalic acid-depleted catholyte portion with a quantity of solid oxalic acid comprises one or more columns comprising solid oxalic acid. 
     
     
         13 . The reaction system according to  claim 11 , comprising a means for intermittently or continuously determining the concentration of oxalic acid in the catholyte loop. 
     
     
         14 . The reaction system according to  claim 13 , wherein said means for withdrawing a portion of an oxalic acid-depleted catholyte from the catholyte loop comprises an outlet port located in the catholyte loop upstream of the catholyte holding tank. 
     
     
         15 . The reaction system according to  claim 13 , wherein said means for withdrawing a portion of an oxalic acid-depleted catholyte from the catholyte loop comprises an outlet port located at the catholyte holding tank. 
     
     
         16 . The reaction system according to  claim 13 , wherein said means for intermittently or continuously determining the concentration of oxalic acid in the catholyte loop is configured to determine the concentration of oxalic acid in the catholyte loop upstream of the cathode compartment.