Role of acid‐base and hydration‐dehydration equilibria on reductions of chloral and chloral hydrate

Abstract: The electrochemical behavior of chloral hydrate in aqueous solutions at various pH values was investigated by using polarography. Reduction of chloral hydrate takes place in two steps: one appears as a small limiting current value that corresponds to the reduction of the unhydrated form, present in solutions in less than 3%, and another larger limiting current value at more negative potentials corresponding to a reduction of C‐Cl bonds in the hydrated form. Reduction schemes for both the hydrated and unhydrated forms and of an oxidation process for chloral hydrate are proposed. The reduction scheme supports the stepwise removal of chloride ions from the hydrated form of chloral that is electroactive in its protonated form, yielding ethanol as the final product. A rate constant for the protonation of chloral hydrate is calculated from its measured pKa value and electrochemical data. The role of hydration‐dehydration equilibria involving the reduction intermediates, which are reduced at more negative potentials than that of chloral, was concluded based on a comparison of limiting currents of chloral hydrate with those of 2,2,2‐trichloroethanol. The alcohol yields, in medium pH range a diffusion‐limited current, corresponding to cleavage of three C‐Cl bonds. This allowed the calculation of the equilibrium constant of the hydration‐dehydration equilibria.

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch

Bibliographic citation
Role of acid‐base and hydration‐dehydration equilibria on reductions of chloral and chloral hydrate ; day:12 ; month:12 ; year:2021 ; extent:9
Electrochemical science advances ; (12.12.2021) (gesamt 9)

Creator
Baymak, Melek Sirin

DOI
10.1002/elsa.202100074
URN
urn:nbn:de:101:1-2021121314002429314446
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
15.08.2025, 7:23 AM CEST

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Associated

  • Baymak, Melek Sirin

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