The use of cryogenic consumables to cool reactions is impractical on scale or over extended reaction times. We have recently published our work [1] that describes the development of a convenient laboratory device that offers chemists the benefits of continuous flow processing using an accurate thermal energy transfer block which provides long-term reaction stability and is free from water ingress.
These units have been designed to avoid the need for consumable cryogenic materials to deliver rapid reaction cooling down, and can provide cooling down to –89°C with little condensation or water ingress over prolonged periods (weeks).
We recently used this cryogenic flow reactor for the preparation of a variety of (hetero)aromatic boronic acids and esters via lithium halogen exchange chemistry [2], diasteroselective fluorination reactions [3], control over gas permeation through a Teflon AF-2400 membrane, preparation of biologically active materials [4] . Most recently we have been developing the use of thermocouples to monitor real time reaction exotherms, liquid-liquid separators to effect inline quenching and extraction, and the ability to monitor and even control the cooling power based on the liquid temperature at the point of mixing.
See Cambridge Reactor Design: FlowSyn Polar BearTM
Publications
1. Continuous cold without cryogenic consumables: development of a convenient laboratory tool for low temperature flow processes D.L. Browne, B.H. Harji, S.V. Ley, Chem. Eng. and Technol. 2013, 36, 959-967.
2. A new enabling technology for convenient laboratory scale continuous flow processing at low temperatures D.L. Browne, M. Baumann, B.H. Harji, I.R. Baxendale, S.V. Ley* Org. Lett. 2011, 13, 3312-3315
3. Studies of a diastereoselective electrophilic fluorination reaction employing a cryo-flow reactor K. Nakayama, D.L. Browne, I.R. Baxendale, S.V. Ley, Synlett 2013, 24, 1298-1302.
4. Scaling Up of Continuous Flow Processes with Gases Using a Tube-in-Tube Reactor: Inline Titrations and Fanetizole Synthesis with Ammonia J.C. Pastre, D.L. Browne, M. O’Brien, S.V. Ley, Org. Process Res. Dev. 2013, 17, 1183–1191
