Two-step continuous flow process of sodium tanshinone IIA sulfonate using a 3D circular cyclone-type microreactor

A sustainable and practical process is presented for the direct synthesis of sodium tanshinone IIA sulfonate (STS). Our approach was inspired by the well-established and industrially applied batch synthetic route for STS production. We constructed a telescoped two-step continuous flow platform. This involved a continuous tanshinone IIA sulfonation and in-line salt formation. For the setup, we constructed a 3D circular cyclone-type microreactor using femtosecond laser micromachining. Compared to the 68% yield for 2 h in batch, the two-step continuous flow had an STS yield of 90%, achieved for a total residence time of < 3.0 min under optimal conditions. The proposed continuous flow method vastly simplified the operation and improved procedural safety, while significantly reducing the required acid content and wastewater production.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

A sustainable and practical approach is presented for the direct synthesis of sodium tanshinone IIA sulfonate (STS). A two-step continuous flow platform was constructed, which achieved a higher yield and improved procedural safety compared to the batch synthetic route. The proposed method also reduced the required acid content and wastewater production.