Molecularly imprinted polymers as stereoselectors in Diels- Alder reactions

Luk, Yvonne Cathy 2013. Molecularly imprinted polymers as stereoselectors in Diels- Alder reactions. MPhil Thesis, Cardiff University. Item availability restricted.

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Abstract

The long term goal of this project was to use the high selectivity, but low binding capacity of MIPs, with the high efficiency of microreactors to increase the yield of a minor isomer. In this initial study, the aim was to develop a polymer system capable of increasing the minor product (exo 6) of a simple Diels- Alder reaction between cyclopentadiene and benzyl acrylate. In the first instance the endo (major) product isomer (endo 6) was used as the MIP template (as more of the isomer was available) and 3 MIPs with different functional monomers- Methacrylic acid, 4- viny pyridine and acrylamide were produced and evaluated. The imprinting effect was observed for both the 4-vinyl pyridine based MIP and the acrylamide based MIP with endo 6 though the imprinting effect for the 4- vinyl pyridine based MIP dropped sharper with increasing endo 6 concentration (difference in MIP and NIP binding dropped from 35 % to 5 % when endo 6 concentration was increased from 10 μM to 50μM) compared to the acrylamide based MIP (30 % to 15 % for the same respective endo 6 concentrations). The reaction between cyclopentadiene and benzyl acrylate was conducted at initial reactant concentrations of 1, 2 and 4 mM and an initial concentration of 2 mM for both reactants would generate a suitable concentration of endo and exo 6 isomers to observe the imprinting effect as the amount of endo 6 generated (67 μM) was low enough to observe specific MIP binding and the amount of exo 6 generated (17 μM) was greater than its detection limit. These results demonstrated that a suitable MIP system was identified and the MIPs produced were able to bind specifically to the product isomer used as the template (endo 6) in MIP production. Furthermore, the ability for the product isomers to be generated in concentrations used in the binding studies was proven. Hence it is reasonable to suggest that MIPs can be used to influence the stereo outcome of the model reaction using the MIP system and reaction conditions identified though more work is required to understand the effect of scaling up MIP and NIP systems and batch variations.

Item Type:	Thesis (MPhil)
Status:	Unpublished
Schools:	Pharmacy
Subjects:	Q Science > Q Science (General)
Uncontrolled Keywords:	Diels-Alder ; Isomer ; MIPs ; cyclopentadiene ; benzyl acrylate
Date of First Compliant Deposit:	30 March 2016
Last Modified:	19 Mar 2016 23:23
URI:	https://orca.cardiff.ac.uk/id/eprint/49987

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