PROCESS FOR THE PRODUCTION OF HYDROQUINONE

1365643 Hydroquinone UNION RHEINISCHE BRAUNKOHLEN KRAFTSTOFF AG 23 Feb 1972 [24 Feb 1971] 8332/72 Heading C2C A process for the production of hydroquinone by the electrochemical oxidation of benzene to quinone and the electrochemical reduction of quinone to hydroquinone comprises passing a finely dispersed recycle stream of benzene, dilute sulphuric acid and quinone, the quinone content of which is no higher than 2% related to the benzene through the anode compartment of an electrolysis cell at a speed sufficient to produce turbulence and passing a finely dispersed recycle stream of benzene dilute sulphuric acid and hydroquinone, substantially free of quinone through the cathode compartment at a speed sufficient to produce turbulence, adding fresh benzene to the anode recycle stream before it is introduced into the anode compartment, removing a corresponding proportion of the anode recycle stream after the anode compartment, separating the sulphuric acid from this component stream and returning it to the anode recycle stream, adding the residual benzenequinone mixture containing no more than about 2% of quinone to the cathode recycle stream before it is introduced into the cathode compartment, removing a corresponding proportion of the cathode recycle stream after the cathode compartment, separating the benzene from this component stream and returning it to the anode recycle stream, separating the hydroquinone from the residual hydroquinone sulphuric acid mixture and returning the sulphuric acid to the cathode recycle stream before it is introduced into the cathode compartment. The process is described with reference to a flow chart (not shown).