Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

7. Substitution Reactions

SN1 Reaction

Organic Chemistry

7. Substitution Reactions

SN1 Reaction

Previous problemNext problem

1:25 minutes

Problem 37

Textbook Question

Propose a mechanism for the reaction of benzyl bromide with ethanol to give benzyl ethyl ether.

Verified step by step guidance

Step 1: Identify the reaction type. This is a nucleophilic substitution reaction where benzyl bromide reacts with ethanol under heat to form benzyl ethyl ether. The bromine atom is replaced by the ethoxy group (-OCH2CH3).

Step 2: Analyze the structure of benzyl bromide. Benzyl bromide contains a benzyl group (C6H5CH2-) attached to a bromine atom. The benzyl group stabilizes the carbocation intermediate formed during the reaction.

Step 3: Ethanol acts as the nucleophile. The oxygen atom in ethanol has lone pairs of electrons, making it nucleophilic and capable of attacking the electrophilic carbon in benzyl bromide.

Step 4: Mechanism initiation. The reaction begins with the cleavage of the C-Br bond in benzyl bromide, forming a benzyl carbocation (C6H5CH2+). This step is facilitated by the heat provided in the reaction conditions.

Step 5: Nucleophilic attack. The lone pair of electrons on the oxygen atom of ethanol attacks the benzyl carbocation, forming a new C-O bond. This results in the formation of benzyl ethyl ether (C6H5CH2OCH2CH3) as the final product.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule by a nucleophile. In this case, the bromine atom in benzyl bromide is replaced by the ethoxide ion (from ethanol) through an SN2 mechanism, where the nucleophile attacks the electrophilic carbon, leading to the formation of the new bond.

Ethanol as a Nucleophile

Ethanol can act as a nucleophile due to the presence of the oxygen atom, which has a lone pair of electrons. When heated, ethanol can deprotonate to form the ethoxide ion (C2H5O-), which is a stronger nucleophile. This ion is crucial for attacking the benzyl carbon in benzyl bromide to form benzyl ethyl ether.

Reaction Conditions and Mechanism

The reaction conditions, including heat, facilitate the nucleophilic substitution process. Heating increases the kinetic energy of the molecules, promoting the reaction rate. Understanding the mechanism, which involves the transition state where the nucleophile and leaving group interact, is essential for predicting the outcome of the reaction and the formation of benzyl ethyl ether.

Watch next

Master Drawing the SN1 Mechanism with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Predict the compound in each pair that will undergo solvolysis (in aqueous ethanol) more rapidly.

(c)

(d)

Textbook Question

Allylic halides have the structure

a. Show how the first-order ionization of an allylic halide leads to a resonance-stabilized cation.

Textbook Question

Often, compounds can be synthesized by more than one method. Show how this 3° alcohol can be made from the following:

(d) a 3° alkyl bromide

Textbook Question

Give the substitution products expected from solvolysis of each compound by heating in ethanol.

(c)

(d)

Textbook Question

Propose a mechanism involving a hydride shift or an alkyl shift for each solvolysis reaction. Explain how each rearrangement forms a more stable intermediate.

Hint: Most rearrangements convert 2° (or incipient 1°) carbocations to 3° or resonance-stabilized carbocations.

(d)

Textbook Question

Predict the products of the following S_N2 reactions.

(c)

(d)

Textbook Question

Choose the member of each pair that will react faster by the SN1 mechanism.

e. 2-iodo-2-methylbutane or tert-butyl chloride

f. 2-bromo-2-methylbutane or ethyl iodide

Textbook Question

When tert-butyl bromide is heated with an equal amount of ethanol in an inert solvent, one of the products is ethyl tert-butyl ether.