Question

Hydration of aldehydes and ketones is a reaction that occurs in the presence of water. What are two factors that determine the extent of hydration, and what are their effects? Put the following compounds in order from the least likely to most likely to be hydrated in the presence of water: formaldehyde, benzaldehyde, 2,2,2-trichloroethanal.

Answer 1

Hydration of the carbonyl compounds result in the formation of gem-diols. The two main important factors that determine the extent of hydration of a carbonyl compound are steric effects and Electronic effects.

Steric hindrance plays an important role in the determining the extent of hydration of a carbonyl compound. This is because when addition of water occurs at the electrophilic centre of the carbonyl compound, the substituent groups are pushed back closer to one another and hence the reactivity decrease with increase in the bulkiness of the substituents.

Strain effects also influence the extent of hydration of a carbonyl compound. If the carbonyl compound is a small carbocyclic chain, then there will be an angle strain that decrease the reactivity of the carbonyl compound towards hydration to form hemiketals.

Electronic factors also determine the strength of hydration of a carbonyl compound. Electron-withdrawing groups facilitate the addition of water at the electrophilic centre of the carbonyl compound.

The order of the carbonyl compound from most likely to least likely towards hydration reaction is as follows:

Hydration of the carbonyl compounds result in the formation of gem-diols. The two main important factors that determine the extent of hydration of a carbonyl compound are steric effects and Electronic effects.

Steric hindrance plays an important role in the determining the extent of hydration of a carbonyl compound. This is because when addition of water occurs at the electrophilic centre of the carbonyl compound, the substituent groups are pushed back closer to one another and hence the reactivity decrease with increase in the bulkiness of the substituents.

Strain effects also influence the extent of hydration of a carbonyl compound. If the carbonyl compound is a small carbocyclic chain, then there will be an angle strain that decrease the reactivity of the carbonyl compound towards hydration to form hemiketals.

Electronic factors also determine the strength of hydration of a carbonyl compound. Electron-withdrawing groups facilitate the addition of water at the electrophilic centre of the carbonyl compound.

The order of the carbonyl compound from most likely to least likely towards hydration reaction is as follows: