Chapter 15

Carboxylic Acids, Esters, and derivatives

Where found

• Tartness in fruits

•

• Rancid butter

•

• Animal fats and plant oil

• Clothing

Structure of Carboxylic Acids

• Presence of the carbonyl group: C=O

• Additional presence of

• Formic acid

• Acetic acid

Structure of Esters

• A carboxylic acid derivative

• Presence

• Methyl propionate

Structure of Acid Anhydrides

• Presence of two carbonyl carbons connected by an oxygen

•

Structure of Amides

• Presence of

• More in chapter 16

Structure of Acid Halide

• Presence of

Synthesis of Carboxylic Acids

• Selective oxidation

• Benzoic acid

• From

Naming Carboxylic Acids

• Longest chain with carboxyl group. The carboxyl carbon is C1

• Ending of –e is changed to –oic acid

• Substituents are used as prefixes with numbers to show location

• Two carboxyl groups are an alkanedioic acid with separate numbers to show location

Items of Interest

• Table 15.2 page 437

• Box 15.1 page 441

Properties of Carboxylic Acids

•

• How do the m.p. and b.p. compare to:– Alkanes?– Alcohols?

• How does solubility compare to:– Alkanes?– Alcohols

Acidity of Carboxylic Acids• Weak acids

•

• Only about 1 to 2% ionization to H+

• HCl is 100% ionized

• Acidic enough to turn blue litmus red

•

Carboxylate Salts

•

• More soluble in higher pH environment (i.e. blood)

•

• Important in biological functions

Properties of Carboxylate Salts

• Ionic molecules– – – –

• Injections of medicine with a carboxyl groups are given with the salt

• The salts are basic – red to blue litmus

Naming Carboxylate Salts

• Positive ion named first

• Change the acid from –ic acid to –ate

• Name:– CH3COO-Na+

– CH3CH2CH2CH2COO-K+

Soaps

• Salts of long chain carboxylic acids (fatty acids – derived from animals and plants)

•

• Conversion process is called

• Sodium stearate CH3(CH2)16COO-Na+

• Need a long chain and ionic head (Fig 15.1)

Esters

• An ester, RCOOR’ is formed

• Process is called esterification

•

•

• Thioesters – involve Sulfur (Thiol) p. 446

Naming Esters

• Two parts– Alkoxy – alcohol (aryloxy for phenol)– Acyl – acid

• The group is named first

• The part is named second and change from –ic acid to –ate

• Name: CH3OOC(CH2)3CH3

Polyesters

• Esterification becomes polymerization if there are two functional groups per molecule– Dicarboxylic acids– Diols

• See page 449• Condensation reaction if water is a by-product• Addition polymerization if no by-products

(alkenes)