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Enhanced mixing of biphasic liquid-liquid systems for the synthesis of gem -dihalocyclopropanes using packed bed reactors
Journal of Flow Chemistry ( IF 2.0 ) Pub Date : 2019-01-07 , DOI: 10.1007/s41981-018-0026-1
Timo von Keutz , David Cantillo , C. Oliver Kappe

A continuous flow procedure for the gem-dichlorocyclopropanation of alkenes has been developed. The method is based on the generation of dichlorocarbene utilizing the classical biphasic aqueous sodium hydroxide/chloroform system. This reaction typically requires vigorous stirring for several hours in batch for completion. Tarry materials precipitate due to partial polymerization of dichlorocarbene and the process is difficult to scale. To overcome these problems and achieve very efficient mixing during the flow process a column reactor packed with PTFE beads as inert filling material has been used. PTFE beads have been found to be the optimal material to obtain fine dispersions of the aqueous phase in the organic solution. By heating the packed-bed reactor at 80 °C excellent conversions have been achieved after a residence time of only 4 min. The process has been applied for the synthesis of Ciprofibrate, a dichlorocyclopropane-containing drug used as treatment for several diseases associated with high lipid content in blood.



中文翻译:

使用填充床反应器增强两相液-液系统的混合,以合成宝石-二卤代环丙烷

宝石的连续流动程序已经开发了烯烃的-二氯环丙烷化。该方法基于利用经典的双相氢氧化钠水溶液/氯仿系统生成二氯卡宾。该反应通常需要分批剧烈搅拌数小时以完成反应。焦油状物质由于二氯卡宾的部分聚合而沉淀,该过程难以规模化。为了克服这些问题并在流动过程中实现非常有效的混合,已使用装有PTFE珠粒作为惰性填充材料的柱式反应器。已经发现,PTFE珠是获得水相在有机溶液中精细分散的最佳材料。通过将填充床反应器加热到80°C,仅停留4分钟即可获得出色的转化率。

更新日期:2019-01-07
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