Scale-up of N-alkylation reaction using phase-transfer catalysis with integrated separation in flow?

Reaction Chemistry & Engineering Pub Date: 2018-11-15 DOI: 10.1039/C8RE00203G

Abstract

A continuous phase-transfer catalysis process for N-alkylation integrated with separation was developed. This approach circumvents the heat and mass transfer limitations encountered in batch scale-up, enabling a safer process and yielding a higher-quality product. Two continuous flow approaches are analyzed: a) an automated fill–empty reactor with an integrated gravity separator and b) a tubular flow reactor with an inline membrane separator. The fill–empty platform enabled the direct technology transfer from batch, achieving conversions >99% (by HPLC) and purities >90%. The tubular flow reactor allowed the reduction of the base solution requirements, yielding conversions of 91% and purities >88%. Both the setups provide a small process footprint with downstream integrated separation. The on-demand scale-up was efficiently and safely demonstrated using the fill–empty approach for the production of various substrates at the multigram scale.

Graphical abstract: Scale-up of N-alkylation reaction using phase-transfer catalysis with integrated separation in flow
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