Electrochemical Tubular Reactor And Its Application In Electrolytic Synthesis Of Succinic Acid

Succinic acid is an important chemical intermediate and raw material, it is used to synthesize a variety of complex organic compounds. Compared with chemical method, preparation of succinic acid by electrolytic synthesis showed an absolute advantage. In this paper, electrochemical tubular reactor was made to prepare succinic acid. The parameters of reactor were optimized by measuring the changes of voltage, yield of succinic, and current efficiency. The performance of reactor was studied and the optimum experimental conditions were discussed.The optimum parameters of reactor used for electrosynthesis of succinic acid were: under atmospheric pressure and ambient temperature, volume of reactor was 850ml, lead and lead alloy as electrodes, distance between electrodes was 2cm, fluid pipe connection of the unit cells was in series, circuit connection was parallel, undivided, self-flowing and continuous reactor.The studies on performance of reactor above-mentioned indicated: the purity and melting point of obtained succinic acid were in line with industry requirements; Cyclic voltammetry and linear sweep curves showed that the electrochemical reduction of maleic acid was irreversible reaction, in which the diffusion process was the rate-determined step; The accelerated life testing showed that life of lead electrode was about 3 months and life of lead alloy electrode was about 1 year; The corrosion resistance testing showed that lead and lead alloy electrode were ideal electrode materials; Over a long period of reaction, electric energy had no effect on improvement of yield; The results of electrolysis were stable when using the technology of mother liquor recycling.The experimental results made by single-factor and orthogonal experiment method showed that the optimum electrolysis technology of preparing succinic acid was defined as follows: current density was 3A·dm^-2, electrolytic temperature was 45～50℃, weight percent of initial maleic acid was 10% and weight percent of sulphuric acid was 5%. The optimal results were achieved: the cell voltage was 3.5～4.2V, the yield of succinic acid was 71～91%, the current efficiency was 65～84% and the purity of succinic acid was more than 99.1 %.This study showed that good electrolytic effects were obtained when the optimum technology was selected to prepare succinic acid by electrolytic synthesis using self-made electrochemical tubular reactor.