Thermodynamic data on enol and enolate formation

In contrast to kinetic data, thermodynamic data on enol and enolate formation are far more scarce. This results from the usually very low enol and enolate stabilities which, at equilibrium, make it difficult to measure their proportions relative to the carbonyl compound. This section deals with available data on keto-enol equilibria as well as on acidity constants of the two tautomers. 

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Enolisation and ionisation are also the first stages of some elimination reactions, aldolisation, alkylation, etc., but in most cases the enolisation (or ionisation) process is not rate-limiting. Thermodynamic data on enol and enolate formation are needed to understand the kinetic behaviour of these reactions, but a complete picture must include data on the subsequent steps. 

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