| Research Abstract |
Epoxidation of olefins is extremely important both in the current industrial process and organic synthesis because epoxide is one of the most useful synthetic intermediates. Most of all commercial epoxidation reactions are indirect, multi-step co-oxidations. Moreover, these processes require a labile, explosive and expensive oxidant such as hydrogen peroxide or tert-butyl hydroperoxide. While, phenol that is also one of the most important chemical in industry, is manufactured by the Cumene process, multi process. Therefore, one-step syntheses of epoxide and phenol are most desirable process in industry.
The purpose in this work is to success simultaneous epoxidation of olefin at anode and hydroxylation of aromatics at cathode during the water electrolysis. First, many anodes were tested for the epoxidation of 1-hexene during the water electrolysis by using the cell, [1-hexene, CH_2Cl_2, anode|H_3PO_4/silica wool|cathode, H_2O/He]. We found that Pt-black anode is the most active for the epoxidation of 1-hexene at room temperature. This Pt-black anode is active for the epoxidation of propylene to propylene oxide at room temperature. During this epoxidation, much H_2 is produced at cathode. We have already reported that the hydroxylation of benzene to phenol during H_2-O_2 fuel cell reactions at cathode. The most active cathode for the formation of phenol is Pd-black+Fe_2O_3/Carbon Whisker. Then, we applied this cathode to the electrolysis cell for epoxidation. We found that simultaneou formation of 1,2-epoxyhexane at anode and formation of phenol at cathode during water electrolysis using the electrolysis cell, [1-hexene, CH_2Cl_2, Pt-black anode|H_3PO_4 aq./silica wool|Pd-balck+Fe_2O_3/CW cathode, benzne, O_2].
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