Electrochemical reduction device and method of manufacturing hydride of aromatic hydrocarbon compound or nitrogen-containing heterocyclic aromatic compound

Abstract

An electrochemical reduction device is provided with an electrolyte membrane, an electrode unit, a power control unit, hydrogen gas generation amount measuring unit, and a control unit. The electrolyte membrane has ion conductivity. The electrode unit includes both a reduction electrode that is provided on one side of the electrolyte membrane and contains a reduction catalyst for hydrogenating at least one benzene ring of an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound, and an oxygen evolving electrode. The control unit releases, when the hydrogen gas generation amount F1 is larger than an acceptable upper limit F0 of a hydrogen gas generation amount in the electrode unit, the application of a voltage by the power control unit.

1 . An electrochemical reduction device comprising:
 an electrolyte membrane having ion conductivity;   an electrode unit including both a reduction electrode that is provided on one side of the electrolyte membrane and contains a reduction catalyst for hydrogenating at least one benzene ring of an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound, and an oxygen evolving electrode provided on the other side of the electrolyte membrane;   a power control unit that applies a voltage Va between the reduction electrode and the oxygen evolving electrode such that the reduction electrode has an electronegative potential and the oxygen evolving electrode has an electropositive potential;   hydrogen gas generation amount measuring unit that measures a generation amount F1 of hydrogen gas generated per unit time of an electrolysis reaction of water that competes with a hydrogenation reaction of at least one benzene ring of the aromatic hydrocarbon compound or the nitrogen-containing heterocyclic aromatic compound; and   a control unit that releases, when the hydrogen gas generation amount F1 is larger than an acceptable upper limit F0 of a hydrogen gas generation amount in the electrode unit, the application of a voltage by the power control unit.   
     
     
         2 . The electrochemical reduction device according to  claim 1  further comprising:
 a reference electrode that is arranged to contact the electrolyte membrane and to be electrically isolated from the reduction electrode and the oxygen evolving electrode and that is held at a reference electrode potential V Ref ; and 
 a voltage detection unit that detects a potential difference ΔV CA  between the reference electrode and the reduction electrode, wherein 
 the control unit measures a potential V CA  in the reduction electrode based on the potential difference ΔV CA  and the reference electrode potential V Ref . 
 
     
     
         3 . An electrochemical reduction device comprising:
 an electrolyte membrane having ion conductivity;   an electrode unit assembly in which a plurality of electrode units are connected in series with each other, the each electrode unit including both a reduction electrode that is provided on one side of the electrolyte membrane and contains a reduction catalyst for hydrogenating at least one benzene ring of an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound, and an oxygen evolving electrode provided on the other side of the electrolyte membrane;   a power control unit that applies a voltage Va between a positive electrode terminal and a negative electrode terminal of the electrode unit assembly such that the reduction electrode of the each electrode unit has an electronegative potential and an oxygen evolving electrode thereof has an electropositive potential;   hydrogen gas generation amount measuring unit that measures, in the whole electrode units, a generation amount F1′ of hydrogen gas generated per unit time of an electrolysis reaction of water that competes with a hydrogenation reaction of at least one benzene ring of the aromatic hydrocarbon compound or the nitrogen-containing heterocyclic aromatic compound; and   a control unit that releases, when the hydrogen gas generation amount F1′ is larger than an acceptable upper limit F0×N (wherein F0 represents an acceptable upper limit of a hydrogen gas generation amount per one of the electrode units, and N the number of the electrode units), the application of a voltage by the power control unit.   
     
     
         4 . The electrochemical reduction device according to  claim 3  further comprising:
 a reference electrode that is arranged to contact the electrolyte membrane of any one of the electrode units included in the electrode unit assembly and to be electrically isolated from the reduction electrode and the oxygen evolving electrode of the electrode unit; and 
 a voltage detection unit that detects a potential difference ΔV CA  between the reference electrode and the reduction electrode of the electrode unit, wherein 
 the control unit measures a potential V CA  in the reduction electrode of the electrode unit based on the potential difference ΔV CA  and the reference electrode potential V Ref . 
 
     
     
         5 . A method of manufacturing a hydride of an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound, comprising:
 using the electrochemical reduction device of  claim 1 ;   introducing an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound into the reduction electrode side of the electrode unit;   circulating water or humidified gas to the oxygen evolving electrode side; and   producing a hydride of the aromatic hydrocarbon compound or the nitrogen-containing heterocyclic aromatic compound introduced into the reduction electrode side.   
     
     
         6 . The method of manufacturing a hydride of an aromatic hydrocarbon compound or a nitrogen-containing heterocyclic aromatic compound according to  claim 5 , wherein
 the aromatic compound or the nitrogen-containing heterocyclic aromatic compound to be introduced into the reduction electrode side is introduced into the reduction electrode side in a liquid state at a reaction temperature.