An amphiphilic and photoswitchable organocatalyst for the aldol reaction based on a product-imprinted polymer

An-Xun ZHENG, Cheng-Bin GONG, Wei-Jing ZHANG, Qian TANG, Hai-Rong HUANG, Cheuk Fai Stephen CHOW

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5 Citations (Scopus)

Abstract

A series of amphiphilic molecularly imprinted polymers (MIP1, MIP2, MIP3, MIP4, MIP5, and MIP6) containing hydrophobic photoresponsive sites and hydrophilic catalytically active sites were fabricated using bifunctional monomers. These polymers were characterized by scanning electron microscopy, N₂ adsorption–desorption analysis, Fourier Transform infrared spectroscopy, thermal gravimetric analysis, and ultraviolet–visible spectroscopy. The catalytic activity of the amphiphilic molecularly imprinted polymer was investigated towards the aldol reaction between p-nitroaldehyde and acetone (a molecular enlargement reaction) in a mixed solvent of DMSO and water at room temperature. The polymer catalyst MIP3 performs best, and displayed good conversions with low catalyst loading (5 mol% of ʟ-hydroxyproline with respect to the aldehyde) and photoswitching properties (photo-regulated conversion difference of 20%). Compared with the corresponding non-imprinted polymer, a higher binding capacity, higher conversion, and better photoswitching properties were obtained when the molecularly imprinted polymer was used as the catalyst, illustrating the importance of the specific cavities in the molecularly imprinted polymer. Copyright © 2017 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)115-125
JournalMolecular Catalysis
Volume442
Early online dateOct 2017
DOIs
Publication statusPublished - 2017

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Polymers
polymers
products
catalysts
Catalysts
Hydroxyproline
Gravimetric analysis
Fourier analysis
Acetone
Dimethyl Sulfoxide
3-hydroxybutanal
Aldehydes
aldehydes
acetone
Fourier transform infrared spectroscopy
catalytic activity
Catalyst activity
thermal analysis
monomers
Monomers

Bibliographical note

Zheng, A.-X., Gong, C.-B., Zhang, W.-J., Tang, Q., Huang, H.-R., & Chow, C.-F. (2017). An amphiphilic and photoswitchable organocatalyst for the aldol reaction based on a product-imprinted polymer. Molecular Catalysis, 442, 115-125.

Keywords

  • Molecularly imprinted polymer
  • Photoswitchable organocatalyst
  • ʟ-Hydroxyproline
  • Aldol reaction
  • Azobenzene