The document summarizes experiments conducted on carboxylic acids and their derivatives. It discusses (1) esterification reactions between acetic acid and ethanol catalyzed by sulfuric acid, (2) using ferric chloride tests to detect phenols and enols, (3) hydrolysis reactions of anhydrides and benzamide producing carboxylic acids and ammonia, and (4) using dicarboxylic acids to remove stains. Key points covered include the mechanisms of esterification and hydrolysis, results of qualitative tests, and observations made during the experiments.

1. Post-Laboratory
Discussion on
Carboxylic Acids &
its derivatives
By Group 2 BMLS-1H
- A molecular model of
Acetylsalicylic acid commonly
known as Aspirin.
For reference, please see page 46 of your Laboratory Manuals

2. Carboxylic Acids
 Also referred to as the “Organic Acids”
 Able to ionize in water
 Polar because of its high electronegativity given by O
 Most frequently encountered organic compounds
 Has a R-C=O group
OH
 Weak acid; Average pH ≈ 5
 High melting point and boiling point
 Polar; soluble in H2O
Definition
- A carboxylic acid
dimeric pair.

3. Esterification
 Ester - a carboxylic salt(carboxylate) most
commonly derived from the reaction of
Carboxylic acid(RCOOH) and Alcohol(ROH) –
“Fischer’s Esterification”.
 Functional group: RCOOR
 a sweet smelling compound
 Reversible reaction
 Catalyst: Strong acid(H2SO4 / HCL)
 Byproduct: H2O(aq)
 Chemical reaction equation:
H2SO4
Definition

4. Esterification
 Other preparations:
 RCOCl + ROH RCOOR + H2O + Pyridinium Chloride
 (RCO2)O + ROH + Pyridine RCOOR + RCOOH
 RCOR + R”COOH(Peroxy acid) RCOOR + RCOOH
Definition

5. 1. Esterification
 Roles of chemicals:
Ethanol – Alcohol
Acetic Acid – Carboxylic Acid
H2SO4 – Catalyst to hasten reaction
NaOH – “Acid” trap to reveal the odor of
ester
Post-Lab

6. 1. Esterification
 Explanation of mechanism:
The experiment yielded a homogenous solution.
Alpha hydrogen of the hydroxyl group of acetic
acid is being removed and bonded with the
deprotonated hydroxyl group of ethanol to form the
byproduct, H2O; the conjugate base of ethanol
bonds with the nucleophile oxygen of the C-O bond
of the acetic acid.
Post-Lab

7. 1. Esterification
 Results and Discussion
 CH3CH2OH + CH3COOH + H2SO4
= hot solution, smells like acetic acid
 CH3CH2OH + CH3COOH + H2SO4 +
= smells like gum
 CH3CH2OH + CH3COOH + H2SO4 + + NaOH
= smells slighty like acetone
Post-Lab

8. 2. Ferric Chloride Test
 Test given to solutions to detect presence
of phenols or enols.
 What are phenols?
Aryl radical with a hydroxyl group.
 What are enols?
Alkenes with a hydroxyl group.
Definition

9. 2. Ferric Chloride Test
Discussion of experiment
 Dilute samples were used for conservation.
 Indicators:
 Purple/Red/Green/Blue- positive
Post-Lab

10. 2. Ferric Chloride Test
 Results and Discussion
 CH3COOH + NaOH = orange precipitate
 Hydroxyl groups were detected but no phenols nor
enols
 CH3COOH + NaOH + HCL = yellow precipitate
 Hydroxyl groups were not that concentrated but
no phenols nor enols
Post-Lab

11. 3. Reaction with Derivatives
 Hydrolysis of an anhydride
 Will lead to two molecules of the carboxylic acid
corresponding the anhydride.
 A reversible reaction
Definition
 Reaction of Diluted NaOH with Benzamide(Hydrolysis)
 Results to benzoate ion and ammonia
 A reversible reaction

12. 3. Reaction with Derivatives
 Results and Discussion
 Hydrolysis of an anhydride
 Immiscibility of acetic anhydride to H2O was
observed.
 Blue litmus paper turned red: Acidic because of
Benzoic Acid
Post-Lab
 Reaction of Diluted NaOH with Benzamide(Hydrolysis)
 Flat and odorless smell = Sodium Benzoate and
Ammonia solution.

13. 4. Reactions with Dicarboxylic Acids
 Dicarboxylic acids
 Organic acids containing two carboxyl(COOH)
groups
Definition

14. 4. Reactions with Dicarboxylic Acids
 Results and Discussions
 The stain was removed.
Post-Lab

15. The end
To God be the Glory!