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Equilibrium constants in reactions of 2-aminoethanol and ammonia with isophthalaldehyde and terephthalaldehyde.

Authors
  • 1
  • 1 Department of Chemistry, Clarkson University, Potsdam, New York 13699-5810, USA.
Type
Published Article
Journal
The journal of physical chemistry. A
Publication Date
Volume
111
Issue
50
Pages
12871–12877
Identifiers
PMID: 18004825
Source
Medline
License
Unknown

Abstract

Equilibria established in reactions between isophthalaldehyde (IPA) and terephthalaldehyde (TPA) on one side and 2-aminoethanol and NH3 on the other side were followed in solutions, where these amines acted both as reagents and as buffers. The equilibrium between TPA and 2-aminoethanol was followed spectrophotometrically; all others, of reactions of TPA with NH3 and of IPA with both NH3 and H2N-CH2CH2-OH, were followed by using polarography. Separate limiting reduction currents of the dialdehyde and its imine enable simultaneous determination of the starting material and the product. The equilibria are shifted more in favor of the imine in reactions of TPA than those of IPA. Equilibrium constants for reactions of both TPA and IPA with 2-aminoethanol are 3 orders of magnitude higher than those observed for the reactions of dialdehydes with NH3, even when the pKa values of these two reagents differ only slightly.

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