Intensification of multiphase processes

Tailby, Matthew 2019. Intensification of multiphase processes. MPhil Thesis, Cardiff University. Item availability restricted.

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Abstract

High Performance Counter Current Chromatography (HPCCC) is a form of liquid-liquid chromatography that employs a biphasic stationary/mobile phase solvent system. The HPCCC machine consists of leads and tubing of either analytical or preparative sizes, which are spun at speeds up to 2100 revolutions per minute (rpm). The resulting velocity and acceleration caused by the spinning creates alternating zones of intense mixing and settling. Up until now, this intense mixing has only been utilised for purification purposes. In this research, biphasic reactions that have previously been limited to batch and flow chemistry, have now successfully been translated into the HPCCC machine, giving accelerated reaction times and superior yields. A monophasic Heck reaction was successfully intensified inside the HPCCC machine, by the introduction of n-hexane as an inert “mixing” phase. The target product was obtained in a 69% yield after 12.5 minutes, outperforming segmented flow (64% after 27 minutes). The increase in yield and decrease in reaction time suggested a much greater mixing efficiency inside the HPCCC machine. The phase transfer catalysed asymmetric alkylation of N-(diphenylmethylene)glycine tertbutyl ester (5) with benzyl bromide, using chiral catalyst (15) as the phase transfer catalyst was successfully intensified in the HPCCC machine. vi The target product was obtained in a 65% yield after 10.7 minutes reaction time, with no reduction in enantioselectivity when compared to batch methods (86% ee). The results obtained from the HPCCC were much higher in yield then that obtained in batch (10%) and flow (26%) for the same reaction time. This clearly confirmed the superior mixing efficiency inside the HPCCC machine.

Item Type:	Thesis (MPhil)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	12 May 2020
Last Modified:	12 May 2021 02:05
URI:	https://orca.cardiff.ac.uk/id/eprint/131576

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