Carboxylic Acids Rnxs

Question 1

Reaction with a base

Answer 1

All CAs react with a base to form water soluble salts and water

Question 2

Fischer esterification

Answer 2

Conversion of an acid to an ester

1. CA + H+ -> C=O+-H
2. Alcohol attacks the CC and attaches through one of the lone pairs on the O group (similar to acetal formation) which gives O a positive charge. The double bond on the O is converted to a single bond, getting rid of the negative charge
3. Proton Transfer- the Extra H atom from the alcohol is moved to one of the OH groups attached to the CC, getting rid of the positive charge
4. Water is eliminated and the remaining OH group double bonds to the CC again.
5. -H+ from the remaining OH group, getting rid of the charge. The final product is complete

Question 3

Reduction

Answer 3

1. First reduced to an aldehyde
2. If more reducing agent is added, it is then converted to an alcohol
   - the mechanism is a nucleophilic substitution followed by nucleophilic addition

Question 4

Selective reduction through catalysis

Answer 4

H2Pt: reduces carbon carbon double bonds but not COOHs
NaBH4/dilute HCl: reduces ketones but not carboxylic acids
LiAlH4: reduces carboxylic acids but not carbon carbon double bonds

Question 5

Conversion to acid halides

Answer 5

Commonly achieved with thionyl chloride (Cl-S=O-Cl)

- COOH + thionyl chloride -> -COCl OR acid COO-S=O-Cl