Isotope Effect in the Reaction of ¹⁴C-Formaldehyde with Dimedone

Abstract

Formulae for the specific activity of a labelled product at any stage in a reaction which involves an " isotope effect " are discussed. The investigation of isotope effect by isolating a labelled product in consecutive fractions is illustrated by the reaction of ¹⁴C-formaldehyde with dimedone. In this reaction the ¹⁴C-formaldehyde reacts 0.927± 0.005 times as rapidly as the unlabelled compound at room temperature. Care must be taken when using dimedone as a derivative for the accurate assay of isotopic formaldehyde if errors due to isotope effect are to be avoided.