Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Bruice8th EditionOrganic ChemistryISBN: 9780135213711Non è quello che usi tu?Cambia libro di testo

Bruice 8th Edition

Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Problema 19b

Capitolo 15, Problema 19b

Which ester hydrolyzes more rapidly? b. phenyl acetate or benzyl acetate?

Guida verificata passo dopo passo

Step 1: Understand the hydrolysis mechanism for esters. Ester hydrolysis typically occurs via nucleophilic attack by water or hydroxide ions on the carbonyl carbon, leading to the cleavage of the ester bond.

Step 2: Analyze the chemical structures of phenyl acetate and benzyl acetate. Phenyl acetate has the phenyl group directly attached to the oxygen atom of the ester, while benzyl acetate has a benzyl group (a phenyl group attached to a CH2 group) attached to the oxygen atom.

Step 3: Consider the electronic effects of the substituents. The phenyl group in phenyl acetate can stabilize the transition state through resonance, making the carbonyl carbon less electrophilic and slowing down hydrolysis. In benzyl acetate, the benzyl group does not directly interact with the carbonyl carbon, so the hydrolysis rate is less affected by resonance stabilization.

Step 4: Evaluate steric effects. The phenyl group in phenyl acetate is bulkier and closer to the carbonyl carbon, which can hinder the approach of nucleophiles and slow down hydrolysis. Benzyl acetate has less steric hindrance near the carbonyl carbon, allowing nucleophiles to attack more easily.

Step 5: Conclude based on the above factors. Benzyl acetate is expected to hydrolyze more rapidly than phenyl acetate due to reduced resonance stabilization and steric hindrance near the carbonyl carbon.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Durata del video:

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Ester Hydrolysis

Ester hydrolysis is a chemical reaction where an ester reacts with water to form an alcohol and a carboxylic acid. This reaction can occur under acidic or basic conditions and is important in organic chemistry for understanding the reactivity of esters. The rate of hydrolysis can be influenced by the structure of the ester, including steric hindrance and electronic effects.

Video consigliato:

Percorso guidato

0:48

Hydrolysis of Phosphate Esters Concept 2

Steric Effects

Steric effects refer to the influence of the spatial arrangement of atoms in a molecule on its reactivity. In the context of ester hydrolysis, bulky groups near the ester bond can hinder the approach of water molecules, slowing down the reaction. Benzyl acetate has a benzyl group that is less sterically hindered compared to the phenyl group in phenyl acetate, potentially affecting the rate of hydrolysis.

Video consigliato:

02:53

Understanding steric effects.

Electronic Effects

Electronic effects involve the influence of electron distribution within a molecule on its chemical behavior. In esters, the presence of electron-donating or electron-withdrawing groups can stabilize or destabilize the transition state during hydrolysis. The benzyl group in benzyl acetate can provide resonance stabilization, which may enhance the hydrolysis rate compared to phenyl acetate, where the phenyl group does not offer the same stabilization.

Video consigliato:

04:29

Activity and Directing Effects

Pratica correlata

Domanda del libro di testo

Which ester hydrolyzes more rapidly? a. methyl acetate or phenyl acetate?

1241

views

Domanda del libro di testo

Write a mechanism for each of the following reactions:

a. the uncatalyzed hydrolysis of methyl propionate.

1119

views

Domanda del libro di testo

Using the mechanism for the acid-catalyzed hydrolysis of an ester as your guide, write the mechanism—showing all the curved arrows—for the acid-catalyzed reaction of acetic acid and methanol to form methyl acetate. Use HB⁺ and :B to represent the proton-donating and proton-removing species, respectively.

1656

views

Domanda del libro di testo

Write a mechanism for each of the following reactions:

b. the aminolysis of phenyl formate, using methylamine.

944

views

Domanda del libro di testo

In the mechanism for the acid-catalyzed hydrolysis of an ester,

c. what species is HB⁺ most likely to be in the hydrolysis reaction?

d. what species is HB⁺ most likely to be in the reverse reaction?

960