GREEN ELECTROCHEMICAL SYNTHESIS OF p-AMINOPHENOL AND INDUSTRIALIZATION
The studies on the industrialization of electrochemical synthesis of p-aminophenol (PAP) from nitrobenzene in a divided electrolytic cell with a rotating Cu-Hg cathode were presented.The experimental results showed that the electrolytic properties are greatly depended on the operation parameters, such as cathode rotating speed, current, temperature, as well as anode materials.The reduction of nitrobenzene to PAP was favored by increasing temperature and cathode rotating speed.Compared with Ti/Ir anode, the Pb-Sb-Sn-Ag-Cu alloy was more suitable as anode material when the cost and operating life were concerned.Industrialization tests of electrochemical synthesis of PAP were conducted at the following conditions: Pb alloy anode material, temperature 90℃, cathode rotating speed 900 r·min -1, current 3000 A.The average current efficiency and conversion ratio of nitrobenzene were 57% and 99% respectively.The average yield of PAP was up to 69.9% and DC power consumption was 7.24 kW·h·(kg PAP) -1.The purity of the product was higher than 98%, and its average melting point was 186.1—187.3℃.