Direct synthesis of diphenyl carbonate by mediated electrocarbonylation of phenol at Pd²⁺-supported activated carbon anode

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• 作者：Toru Murayama^a ; Tomohiko Hayashi^a ; Yuji Arai^a ; Ichiro Yamanaka ; ^a ; ^{yamanaka@apc.titech.ac.jp}
• 关键词：Diphenyl carbonate ; Alternative phosgene method ; Pd electrocatalysis ; Carbonylation ; Sustainable chemistry
• 刊名：Electrochimica Acta
• 出版年：2011
• 出版时间：28 February 2011
• 年：2011
• 卷：56
• 期：7
• 页码：2926-2933
• 全文大小：454 K

文摘

Mediated electrocarbonylation of phenol to diphenyl carbonate (DPC) at a PdCl₂-supported activated carbon anode in 1 atm CO at 298 K was studied. A dry CH₂Cl₂ or CH₃CN solvent and a galvanostatic electrolysis of 1 mA were necessary for formation of DPC, while the addition of a base and a supporting electrolyte was also essential. A combination of triethylamine (Et₃N) and tetrabutylammonium perchlorate (Bu₄NClO₄) was suitable in various combinations. The addition of 2 equiv. of Et₃N to the electrolyte (C₆H₅OH/Bu₄NClO₄/CH₂Cl₂) at 1-h intervals was more efficient in the formation of DPC than a single initial addition of the same amount of Et₃N. The yield of DPC was 130 % based on Pd and its current efficiency (CE) was 42 % for 6 h. The CE of the CO₂ formation was only 3 % . Sodium phenoxide (PhONa) showed dual functionality as a base and supporting electrolyte. When the mediated electrocarbonylation was conducted in a C₆H₅OH/PhONa/CH₃CN electrolyte, DPC was produced in 172 % yield and 40 % CE for 6 h. The CE of the CO₂ formation was 10 % . DPC formed continuously after a single initial addition of 4 equiv. of PhONa. Li or K phenoxide also worked as promoters for the mediated electrocarbonylation of phenol to DPC.