有机化学 ›› 2021, Vol. 41 ›› Issue (4): 1683-1690.DOI: 10.6023/cjoc202009044 上一篇    下一篇

研究论文

甲烷与三氯化铁的光化学反应在环境温度下实现甲烷的选择性氯化反应

霍尚飞1, 陈鸿1, 左伟伟1,*()   

  1. 1 东华大学材料科学与工程学院 纤维材料改性国家重点实验室 上海 201620
  • 收稿日期:2020-09-20 修回日期:2020-11-15 发布日期:2020-12-10
  • 通讯作者: 左伟伟
  • 基金资助:
    国家自然科学基金(21772021)

Selective Chlorination of Methane Photochemically Mediated by Ferric Chloride at Ambient Temperature

Shangfei Huo1, Hong Chen1, Weiwei Zuo1,*()   

  1. 1 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620
  • Received:2020-09-20 Revised:2020-11-15 Published:2020-12-10
  • Contact: Weiwei Zuo
  • About author:
    * Corresponding author. E-mail:
  • Supported by:
    National Natural Science Foundation of China(21772021)

在温和条件下选择性活化与转化甲烷具有可观的经济效益, 但同时也是难点. 报道在环境温度条件下, 无水三氯化铁(FeCl3)与甲烷在环境温度下的光化学反应, 这是一种有效的选择性活化甲烷生成一氯甲烷的方法. 在300 W的高压汞灯或者太阳光的照射下, 由甲烷转化的产物为单一的一氯甲烷, 而没有其它多氯代物, 最大初始生成效率为43 gMeCl?(kgFe?h)–1. 氯化铁既作为氯自由基源, 也作为氧化剂, 并在反应中被还原为氯化亚铁. 高压汞灯功率增加以及氯化铁浓度增加都会加快初始反应速率. 而反应温度以及甲烷的压力对反应的初始速率影响很小. 氯甲烷可以被水解为甲醇, 亚铁在空气以及盐酸存在下也可以被重新氧化为三价铁, 从而完成铁和氯的循环.

关键词: C—H活化, 甲烷活化与转化, 金属催化合成反应, 光催化

Selective activation of methane under mild conditions to produce functionalized products is highly lucrative but remains challenging. The photochemical reaction of anhydrous ferric chloride (FeCl3) with methane at ambient temperature is an efficient process to selectively chlorinate methane to methyl chloride. An exclusive formation of methyl chloride instead of other multi-chlorinated products is observed, and a maximum initial productivity of 43 gMeCl?(kgFe?h)–1 was obtained under irradiation with a 300-watt high-pressure mercury lamp or solar light. Ferric chloride functions both as the source of reactive chlorine radicals and as the oxidant, and it was concomitantly reduced to ferrous chloride. The reaction rate increases with the power of the lamp and the concentration of ferric chloride. Interestingly, the reaction temperature from 25 to 75 ℃ and the methane pressure in the range of 1~4 MPa had little influence on the reaction rate. Methyl chloride was hydrolyzed to methanol with elimination of hydrogen chloride, and the ferrous product was re-oxidized to the ferric analog by oxygen in the air in the presence of hydrogen chloride, thus completing the loop of both iron and chlorine.

Key words: C—H activation, methane activation and functionalization, metal-catalyzed synthetic reaction, photocatalysis