Aminated poly(ethylene glycol) methacrylate resins as stable heterogeneous catalysts for the aldol reaction in water
[2];
[5]
- Ghent Univ. (Belgium). Lab. for Chemical Technology (LCT; OSTI
- Ghent Univ. (Belgium). Industrial Catalysis and Adsorption Technology (INCAT)
- Ghent Univ. (Belgium). Center for Ordered Materials, Organometallics and Catalysis (COMOC)
- Georgia Institute of Technology, Atlanta, GA (United States)
- Ghent Univ. (Belgium)
Amine functionalized silicas have frequently been investigated as potential aldol reaction catalysts. However, active site leaching due to hydrolysis cannot be avoided, limiting the long-term stability of these catalysts in aqueous aldol reactions. Therefore, novel catalysts based on an organic resin have been developed starting from a suspension polymerized poly(ethylene glycol) methacrylate (PEGMA) hydrogel with poly(ethylene glycol) dimethacrylate (PEGDMA) as cross-linker. Amine functionalization was performed by chlorination of the terminal hydroxyl groups in the resulting PEGMA resin and subsequent nucleophilic substitution with an amine precursor, i.e., ethylenediamine (EDA), N,N'-dimethylethylenediamine (DED), or methylamine (MA). Additionally, the successful synthesis of the catalysts was confirmed by 13C NMR, FT-IR, and elemental CHN analysis. Performance evaluation in a batch reactor for the aqueous aldol reaction of acetone with 4-nitrobenzaldehyde resulted in a turnover frequency (TOF) of the PEGMA-EDA catalyst amounting to 6.3 ± 0.4 · 10-4 s-1, which is of the same order of magnitude as that of the corresponding state-of-the-art amine functionalized silica evaluated using hexane as solvent. The PEGMA-DED catalyst exhibited a somewhat lower TOF of 3.1 ± 0.2 · 10-4 s-1, while the PEGMA-MA catalyst did not exhibit any turnover, indicating that the secondary amine in the backbone of the active site in the PEGMA-EDA catalyst is inactive. Continuous-flow evaluation of the PEGMA-EDA catalyst in a packed-bed reactor indicated that, as opposed to a primary amine functionalized silica catalyst, a stable catalytic activity as a function of time on stream could be achieved for at least 8 h and, hence, that no deactivation has occurred in this timeframe.
- Research Organization:
- Georgia Institute of Technology, Atlanta, GA (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Science (SC)
- Grant/Contract Number:
- FG02-03ER15459
- OSTI ID:
- 1800091
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: C Vol. 381; ISSN 0021-9517
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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