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

22. Carboxylic Acid Derivatives: NAS

Saponification

Organic Chemistry

22. Carboxylic Acid Derivatives: NAS

Saponification

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2:46 minutes

Problem 17b

Textbook Question

Soap manufacturers always use base to hydrolyze fats, and never acid. Suggest two reasons that basic hydrolysis is preferred.

Verified step by step guidance

Understand the process of hydrolysis: Hydrolysis of fats (triglycerides) involves breaking the ester bonds in the triglyceride molecule to produce glycerol and fatty acid salts. This can be done using either acidic or basic conditions.

Reason 1: In basic hydrolysis (saponification), the fatty acids produced are immediately converted into their salt form (soap) by reacting with the base. This is advantageous because the soap (fatty acid salts) is water-soluble and can be easily separated from the reaction mixture.

Reason 2: In acidic hydrolysis, the fatty acids remain in their protonated form, which are not water-soluble. This makes the separation process more difficult and less efficient compared to basic hydrolysis.

Additional consideration: Basic hydrolysis is generally faster and more efficient than acidic hydrolysis because the hydroxide ion (OH⁻) is a stronger nucleophile than water, facilitating the cleavage of the ester bonds in triglycerides.

Practical aspect: Bases like NaOH or KOH are cheaper, safer, and easier to handle compared to strong acids, making the process more cost-effective and industrially viable for soap production.

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Key Concepts

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

Saponification

Saponification is the chemical reaction between a fat or oil and a base, typically sodium hydroxide or potassium hydroxide, resulting in the formation of soap and glycerol. This process is essential in soap manufacturing, as it effectively breaks down triglycerides into fatty acid salts (soaps) and glycerin, making it a preferred method over acid hydrolysis.

Alkaline Conditions

Basic conditions are more effective for hydrolyzing fats because they promote the complete conversion of triglycerides into soap. In alkaline environments, the reaction proceeds more efficiently, yielding higher soap yields compared to acidic conditions, which may lead to incomplete hydrolysis and the formation of free fatty acids instead of soap.

Safety and Handling

Using a base for hydrolysis is generally safer in industrial settings compared to acids. Bases like sodium hydroxide are less corrosive to equipment and safer for workers when handled properly, while strong acids can pose significant health risks and require more stringent safety measures, making basic hydrolysis a more practical choice for soap manufacturers.

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Related Practice

Textbook Question

Predict the products and propose mechanisms for the following reactions.

(b)

Textbook Question

Suppose we have some optically pure (R)-2-butyl acetate that has been 'labeled' with the heavy ¹⁸O isotope at one oxygen atom as shown.

(a) Draw a mechanism for the hydrolysis of this compound under basic conditions. Predict which of the products will contain the ¹⁸O label. Also predict whether the butan-2-ol product will be pure (R), pure (S), or racemized.

Textbook Question

Propose a mechanism for the base-promoted hydrolysis of γ-butyrolactone:

Textbook Question

Explain why we speak of acidic hydrolysis of an ester as acid-catalyzed, but of basic hydrolysis as base-promoted.

Textbook Question

Predict the products of saponification of the following esters.

(a)

Textbook Question

Predict the products of saponification of the following esters.

(b)

Textbook Question

Predict the products of saponification of the following esters.