Efficient Synthesis of Pentaerythritol in a Continuous Microreaction System

The rapid and highly selective synthesis of pentaerythritol has always been a challenge due to many side reactions accompanied by the aldol reaction. Here, the primary side reaction mechanism of the pentaerythritol synthesis process is identified, a reaction process with segmental addition of alkali was proposed, and a microreaction system for intensifying and regulating the homogeneous aldol reaction was constructed and combined with a batch reactor for conducting the Cannizzaro reaction to realize the rapid and highly selective synthesis of pentaerythritol. Based on the excellent mixing performance of the microreactor and the accurate control of the temperature, the aldol reaction was completed within 3 min, and the total reaction time for the synthesis of pentaerythritol was significantly reduced to 1/8 of the traditional process. The yield of pentaerythritol reached 88%, and the total yield containing dipentaerythritol and bicationerythritol methylal was more than 95%, which is comparable to that in the industrial process, 87–94%.