Electrochemical reduction device and method for manufacturing hydride of aromatic compound

A method for manufacturing a hydride of an aromatic compound, the method comprising:

• causing an aromatic compound to be passed through a reduction electrode of a plurality of respective electrode units in order, the electrode unit each comprising:
• (i) an electrolyte membrane having ionic conductivity;
• (ii) a reduction electrode that is provided on one side of the electrolyte membrane and that contains a reduction catalyst for hydrogenating at least one benzene ring of the aromatic compound;
• and (iii) an oxygen evolving electrode that is provided on the other side of the electrolyte membrane, and circulating water or a humidified gas to the oxygen evolving electrode;
• hydrogenating at least one benzene ring of the aromatic compound introduced to the reduction electrode, by applying a voltage Va(i) between the oxygen evolving electrode and the reduction electrode of each of the electrode units, wherein i is a sign for distinguishing individual electrode units;
• adjusting the amount of an organic liquid including the aromatic compound to be supplied to each of the reduction electrodes per unit time according to the concentration M (i) of the aromatic compound to be supplied to the reduction electrode of each of the electrode units until the concentration M (i) reaches a concentration lower limit value set for each of the electrode units;
• transferring the organic liquid including the aromatic compound to the electrode units of the downstream side and then progresses each of the hydrogenations when the concentration M (i) reaches the concentration lower limit value set for each of the electrode units;
• and
• increasing the amount of the organic liquid to be supplied to the reduction electrode when the concentration of the aromatic compound is decreased.