Simultaneous Epoxidation of Olefin and Hydroxylation of Aromatics during Water Electrolysis

烯烃的环氧化反应在当前的工业过程和有机合成中都是非常重要的，因为环氧化物是最有用的合成中间体之一。大多数商业环氧化反应都是间接的、多步骤的共氧化反应。此外，这些过程需要一种不稳定、易爆和昂贵的氧化剂，如过氧化氢或叔丁基氢过氧化氢。同时，苯酚也是工业上最重要的化学品之一，是由异丙苯法、多工艺生产的。因此，环氧化物和苯酚的一步合成是工业上最理想的工艺。本工作的目的是在水电解过程中同时实现阳极上的烯烃环氧化和阴极上的芳烃羟基化。首先，用电解槽[1-己烯，CH2Cl2，阳极|H_3PO_4/硅棉|阴极，H_2O/He]测试了水电解过程中1-己烯的环氧化反应。结果表明，在室温下，铂黑阳极对1-己烯的环氧化反应活性最高。这种铂黑色阳极在室温下对丙烯环氧化制环氧丙烷具有活性。在这个环氧化过程中，阴极产生了大量的氢。我们已经报道了H_2-O_2燃料电池在阴极反应中苯的羟基化反应。生成苯酚活性最高的阴极是Pd黑+Fe_2O_3/碳晶须。然后，我们将该阴极应用于电解槽中进行环氧化。我们发现，在电解槽[1-己烯，CH_2Cl_2，铂黑色阳极|H_3PO_4Aq./硅棉|Pd-BLACK+Fe_2O_3/CW阴极，苯，O_2]的电解水过程中，阳极生成1，2-环氧己烷，阴极生成苯酚。

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].