Continuous Flow Synthesis under High-Temperature/High-Pressure Conditions Using a Resistively Heated Flow Reactor

A cheap, easy-to-build, and effective resistively heated reactor for continuous flow synthesis at high temperature and pressure is herein presented. The reactor is rapidly heated directly using an electric current and is capable of rapidly delivering temperatures and pressures up to 400 °C and 200 bar, respectively. High-temperature and high-pressure applications of this reactor were safely performed and demonstrated by selected transformations such as esterifications, transesterifications, and direct carboxylic acid to nitrile reactions using supercritical ethanol, methanol, and acetonitrile. Reaction temperatures were between 300 and 400 °C with excellent conversions and good to excellent isolated product yields. Examples of Diels–Alder reactions were also carried out at temperatures up to 300 °C in high yield. No additives or catalysts were used in the reactions.