Continuous stirred tank reactors in fine chemical synthesis for efficient mixing, solids-handling, and rapid scale-up

Abstract

Continuous stirred tank reactors (CSTRs) facilitate chemical manufacture in continuous flow and have been used for decades. They excel at solid handling and have well understood scale-up capacity. CSTRs in series (CSTR cascades) improve residence time distribution control by exhibiting pseudo plug flow characteristics. Advanced CSTR systems incorporate multiple vessels into a single reactor to simplify design and improve reliability. This review discusses the benefits and limitations of single CSTR technology and CSTR cascades in pharmaceutical and fine chemical synthesis compared with batch, coil (tubular) and plate reactors. In addition, we cover the measurement and importance of residence time distribution in chemical and crystallisation processes. CSTRs demonstrate substantial benefits compared with batch of up to 31% yield increase, 70% cost, and 80% energy reduction. In addition, such continuous manufacturing reduces operational complexity, reliability, and plant footprint.