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Self- and Cross-Aldol Condensation of Propanal Catalyzed by Anion-Exchange Resins in Aqueous Media

Pyo, Sang-Hyun LU ; Hedström, Martin LU ; Lundmark, Stefan; Rehnberg, Nicola and Hatti-Kaul, Rajni LU (2011) In Organic Process Research & Development 15(3). p.631-637
Abstract
Carbon-carbon bond formation using strong and weak anion-exchange resins as green catalysts for self- and cross-aldol condensation of propanal in aqueous media was investigated. The reaction pathway followed the route of aldol condensation to a beta-hydroxy aldehyde and dehydration to an alpha,beta-unsaturated aldehyde. The resulting products were further converted to hemiacetal, and/or acetal moieties, which were confirmed by FT-IR and NMR. In self-condensation using strong anion-exchange resin, 97% conversion of propanal was achieved with 95% selectivity to 2-methyl-2-pentenal within 1 h using 0.4 g/mL resin at 35 degrees C. The conversion and selectivity using weak anion exchanger was lower. During cross-aldol condensation of propanal... (More)
Carbon-carbon bond formation using strong and weak anion-exchange resins as green catalysts for self- and cross-aldol condensation of propanal in aqueous media was investigated. The reaction pathway followed the route of aldol condensation to a beta-hydroxy aldehyde and dehydration to an alpha,beta-unsaturated aldehyde. The resulting products were further converted to hemiacetal, and/or acetal moieties, which were confirmed by FT-IR and NMR. In self-condensation using strong anion-exchange resin, 97% conversion of propanal was achieved with 95% selectivity to 2-methyl-2-pentenal within 1 h using 0.4 g/mL resin at 35 degrees C. The conversion and selectivity using weak anion exchanger was lower. During cross-aldol condensation of propanal with formaldehyde, 3-hydroxy-2-methyl-2-hydroxymethylpropanal was obtained as the main product through first and second cross-condensation followed by hydration reaction in acidic aqueous conditions. The strong anion-exchange resin provided maximal propanal conversion of 80.4% to the product with 72.4% selectivity after 7 h reaction at 35 degrees C and resin concentration of 1.2 g/mL. Using weak anion-exchange resin, the optimal conversion of propanal was 89.9% after 24 h at 0.8 g/mL resin and 35 degrees C, and the main product was 3-hydroxy-2-methylpropanal by first cross-aldol condensation along with relatively minor amounts of methacrolein and 3-hydroxy-2-methyl-2-hydroxymethylpropanal. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Organic Process Research & Development
volume
15
issue
3
pages
631 - 637
publisher
The American Chemical Society
external identifiers
  • wos:000290747700017
  • scopus:79957529797
ISSN
1083-6160
DOI
10.1021/op200004p
language
English
LU publication?
yes
id
46644aed-abdd-4060-ac3a-a27980f6d7f6 (old id 1986286)
date added to LUP
2011-06-29 12:26:36
date last changed
2017-01-01 03:25:41
@article{46644aed-abdd-4060-ac3a-a27980f6d7f6,
  abstract     = {Carbon-carbon bond formation using strong and weak anion-exchange resins as green catalysts for self- and cross-aldol condensation of propanal in aqueous media was investigated. The reaction pathway followed the route of aldol condensation to a beta-hydroxy aldehyde and dehydration to an alpha,beta-unsaturated aldehyde. The resulting products were further converted to hemiacetal, and/or acetal moieties, which were confirmed by FT-IR and NMR. In self-condensation using strong anion-exchange resin, 97% conversion of propanal was achieved with 95% selectivity to 2-methyl-2-pentenal within 1 h using 0.4 g/mL resin at 35 degrees C. The conversion and selectivity using weak anion exchanger was lower. During cross-aldol condensation of propanal with formaldehyde, 3-hydroxy-2-methyl-2-hydroxymethylpropanal was obtained as the main product through first and second cross-condensation followed by hydration reaction in acidic aqueous conditions. The strong anion-exchange resin provided maximal propanal conversion of 80.4% to the product with 72.4% selectivity after 7 h reaction at 35 degrees C and resin concentration of 1.2 g/mL. Using weak anion-exchange resin, the optimal conversion of propanal was 89.9% after 24 h at 0.8 g/mL resin and 35 degrees C, and the main product was 3-hydroxy-2-methylpropanal by first cross-aldol condensation along with relatively minor amounts of methacrolein and 3-hydroxy-2-methyl-2-hydroxymethylpropanal.},
  author       = {Pyo, Sang-Hyun and Hedström, Martin and Lundmark, Stefan and Rehnberg, Nicola and Hatti-Kaul, Rajni},
  issn         = {1083-6160},
  language     = {eng},
  number       = {3},
  pages        = {631--637},
  publisher    = {The American Chemical Society},
  series       = {Organic Process Research & Development},
  title        = {Self- and Cross-Aldol Condensation of Propanal Catalyzed by Anion-Exchange Resins in Aqueous Media},
  url          = {http://dx.doi.org/10.1021/op200004p},
  volume       = {15},
  year         = {2011},
}