Continuous flow supercritical carbon dioxide (scCO 2 ) has previously been shown (P. Stephenson, P. Licence, S. K. Ross, M. Poliakoff, Green Chem. 2004, 6, 521) to be a viable medium for conducting continuous asymmetric hydrogenation when it is combined with an appropriate enantioselective catalyst. Here we examine the use of a composite catalyst immobilisation system modified with several different types of asymmetric bisphosphine ligands in continuous flow scCO 2 . In particular, proprietary ligands from Solvias AG were found to be the most successful, with Josiphos 001 improving the enantiomeric excess (ee) to> 80 % in the asymmetric hydrogenation of dimethyl itaconate (DMIT); this ee is higher than that reported for the batch hydrogenation of DMIT using a homogeneous catalyst fully dissolved in scCO 2 (S. Lange, A. Brinkmann, P. Trautner, K. Woelk, J. Bargon, W. Leitner, Chirality 2000, 12, 450).

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The sections in this article are Introduction Infrastructure for High‐pressure Experiments Location Gas Supply, Compression, and Purification High‐pressure Reactors Materials of Construction for High‐pressure Reactors Metal Components Sealing Materials Reactor Design General Considerations Pressure Vessels for Batch Processing Continuous Flow Reactors Auxiliary Equipment and Handling Tubes and Fittings Valves Pressure Transmitter and Manometer Reactor Heating and Temperature Control Stirrer Types Optical Windows Pressure Safety Valves and Bursting Discs Online Sampling Inline Spectroscopic Measurements Reactor Cleaning Cleaning with Organic Solvents Cleaning with Heated Solvents Cleaning with Acids Cleaning with a Combination of Organic Solvent and sc CO 2 Dosage Under a High‐pressure Regime Dosage of Gases Safety Warnings Dosing in Batch Processes Dosage for Continuous Flow Processes Dosage of Liquids Dosage of Solids Further Regulations and Control in Flow Systems Supply Pressure Reactor Pressure Flow and Total Volume Measurement of Depressurized Gas Streams Evaporation and Condensation Evaporation Condensation Complete Reactor Systems for Synthesis with SCFs Standard Batch Reactor System Essential equipment Brief Description of Work Steps Fully Automated System for Continuous Flow Operation Conclusion