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

21. Aldehydes and Ketones: Nucleophilic Addition

Acetal

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Acetal

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2:43 minutes

Problem 54e

Textbook Question

What are the products of the following reactions?
e.

Verified step by step guidance

Step 1: Identify the functional groups in the reactants. The starting material is an aldehyde (CH3CH2CHO), and methanol (CH3OH) is the alcohol reagent. HCl is the acid catalyst.

Step 2: Recognize the reaction type. This is an acid-catalyzed nucleophilic addition reaction, specifically the formation of a hemiacetal or acetal depending on the conditions. Since methanol is in excess, the reaction will likely proceed to form an acetal.

Step 3: Understand the mechanism. The aldehyde carbonyl group is protonated by HCl, increasing its electrophilicity. Methanol then acts as a nucleophile, attacking the carbonyl carbon to form a tetrahedral intermediate.

Step 4: The intermediate loses water, forming a methoxy group (-OCH3). A second molecule of methanol attacks the carbonyl carbon, leading to the formation of a second methoxy group (-OCH3). This results in the acetal product.

Step 5: Write the final product structure. The acetal product will have two methoxy groups (-OCH3) attached to the original carbonyl carbon, replacing the aldehyde functional group. The structure will be CH3CH2C(OCH3)2.

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Key Concepts

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

Aldehyde Reactivity

Aldehydes are highly reactive carbonyl compounds characterized by the presence of a carbonyl group (C=O) bonded to at least one hydrogen atom. This reactivity allows them to undergo various nucleophilic addition reactions, including the formation of acetals when reacted with alcohols in the presence of an acid catalyst.

Acetal Formation

Acetals are formed when an aldehyde reacts with an alcohol in the presence of an acid catalyst, such as HCl. The reaction involves the nucleophilic attack of the alcohol on the carbonyl carbon, followed by the elimination of water and the formation of a stable acetal structure, which consists of two alkoxy groups attached to the same carbon atom.

Role of Acid Catalyst

An acid catalyst, like HCl, is crucial in the acetal formation process as it protonates the carbonyl oxygen, increasing the electrophilicity of the carbonyl carbon. This enhances the nucleophilic attack by the alcohol, facilitating the reaction and driving it towards the formation of the acetal product, especially when excess alcohol is present.

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