Eltekoff hydrolysis

What is Eltekoff hydrolysis?

Eltekoff discovered a reaction in 1873 wherein olefinic halides were hydrolyzed in aqueous alkali solution to produce glycol, which subsequently formed carbonyl compounds (aldehyde or ketone). The original method involved heating the olefinic halides with lead oxide and water at 140-150ºC, resulting in the formation of acetaldehyde and ethylene glycol from ethylene bromide (or chloride), acetone and propionaldehyde from propylene halides, and so on.

Eltekoff hydrolysis - general reaction scheme
Eltekoff hydrolysis

R1, R2 = alkyl, aryl

Eltekoff also observed that the yield of the carbonyl compound increased with the reaction time, indicating that the carbonyl compounds were generated from the dehydration of glycols in a slightly acidic solution. It was later discovered that lead oxide or high temperature was not required for this reaction, and olefinic halides could be easily hydrolyzed to glycols but not directly to carbonyl compounds when treated with aqueous alkali solution. If the alkali is omitted, glycols may rearrange into carbonyl compounds (a type of pinacol rearrangement in a slightly acidic solution). It is believed that this reaction occurs via an ASE2 mechanism under acidic conditions. This reaction has become one of the most convenient methods for producing ketones.

Glycols, aldehydes, and ketones have been synthesized using this reaction.

References

  • Eltekoff, A., Ber., 1873, 6, 558
  • Eltekoff, A., Ber., 1878, 11, 989
  • Eltekoff, A., Ber., 1878, 11, 990
  • Eltekoff, A., J. Russ. Phys. Chem. Soc., 1878, 10, 215
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