L. 11 Aromatics & Carboxylic Acids

Question 1

Carboxylic Acid

Pka

Group/s

Suffix

Answer 1

• Pka = 4
• Group = Carbonyl + Hydroxyl
• Suffix = -oic acid, Salts = -oate, and dicarboxylic = -dioic acids

Always terminal groups & most oxidized functional group

Question 2

How are cyclic carboxylic acids named

Answer 2

• List the cycloalkane first
• The suffix will be carboxylic acid

Question 3

How are salts of Carboxylic Acids Named

Answer 3

1. First is the cation
2. Ending in -**aote

“Sodium Hexanoate”

Question 4

Physical Properties of Carboxylic Acids

Answer 4

1. Polar & Hydrogen bond (creating DIMERS in solution)
2. Acidity is enhanced by the Resonance between its oxygen atoms
3. Further enhanced by substituents that are electron-withdrawing, and decreased by electron-donating.
4. Beta-dicarboxylic acids, like other 1,3-dicarbonyl compounds, have alpha hydrogen that is highly acidic.

Question 5

How is a Carboxylic acid Synthesized?

Answer 5

Oxidation of Aldehydes & 1º Alcohols by

using oxidizing agents like

KMnO_{<strong>4 (potassium permanganate)</strong>}

or

Na₂Cr₂O_{7 -} K₂Cr₂O_{7(dichromate salts)}

_or

or CrO_{3 (Chromium trioxide)}

Question 6

Steps for a Nucleophilic Acyl Substitution

Answer 6

Acyl; is a Carboxylic acid derivative carbonyl

1. Carbonyl is open via attack
2. Tetrahedral intermediate is formed
3. Carbonyl reforms, kicking off the leaving group.

Question 7

If incoming Nucleophile is ammonia or an amine, what forms?

Suffix?

Cyclic Name?

Answer 7

An AMIDE is form

Suffix -amide

Cyclic amides are Lactams

• Alkyl groups on the nitrogen are placed at beginning of name with N-
• Acidic or basic conditions

Question 8

If incoming nucleophile is an alcohol, what is formed?

Suffix?

Cyclic form?

Answer 8

An ESTER is formed

suffix; -oate

Cyclic esters are named Lactones

• Happens most rapidly with primary alcohols
• Acidic conditions
• Esterification = Condensation Rxn

Question 9

If the Nucleophile is another carboxylic acid, what is formed?

Suffix?

Answer 9

An ANHYDRIDE

Suffix; anhydride

Question 10

Carboxylic acids can be reduced to what?

By what reagent?

Answer 10

Carboxylic acids can be reduced to ALDEHYDES (intermediated)

but can also be reduced to PRIMARY ALCOHOLS.

With LiAlH_{<strong>4 </strong>(lithium aluminum hydride)}

NaBH4 is also a reducing agent but not strong for this specific reaction.

Question 11

What is decarboxylation?

What compounds undergo decarboxylation spontaneously?

Answer 11

Decarboxylation is a chemical reaction that removes a carboxyl group (replaced with hydrogen) and releases carbon dioxide (CO₂). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain.

The enol form is the tautomerized to the most stable keto form…

beta-keto Acids and Beta-dicarboxylic Acids

undergo spontaneous decarboxylation when heated, this proceeds via a six-membered cyclic intermediate.

Question 12

What is Saponification?

Answer 12

Mixing long-chain carboxylic acids (Fatty acids) with a strong base

(Na or K hydroxide) results in the formation of salt we call Soap.

• Soaps hydrophilic carboxylate head and hydrophobic alkyl chain tails.
• Soaps organize in hydrophilic environments to form micelles. A micelle dissolves nonpolar organic molecules in its interior and can be solvated with water due to its exteriro shell of hydrophilic groups.