5.10 Structure of EstersAn ester is a carboxylic acid

OH

O

RO

O

with the acidic H replaced with an R group

5

4

3

5.11 Preparation of esters• Esters are produced from the condensation of a

carboxylic acid

OH

O

HO

HO

HO

O

and alcohol

Preparation of esters movie

• D:\Movies\ester acid esterification.mov

Fig. 5.12

5.12 Naming esters

Alcohol name + acid root “ate”

Esters have an alcohol part and an acid part

NAME:

Table 5.4 Esters that are used as flavoring agents

5.13 Common Esters

1.Alcohol

2.Acid

5.14 Isomerism in Carboxylic acids and esters

• Constitutional isomers exist between carboxylic acids and esters

• Constitutional isomers exist between esters

Table 5.5 Boiling points of compounds with similar molecular weights

5.15 Physical properties of esters

Fig. 5.14 Ester-water hydrogen bonding

→Fig. 5.15 Methyl and ethyl esters of unbranched-chain carboxylic acids at room temperature and pressure.

Carboxylic Acids, Esters, and Other Acid Derivatives cont’d

5.16 Reactions of EstersHydrolysis Reactions

1. Acid hydrolysis

2. Base hydrolysis (saponification)

O

O-O

O

O+H2O

NaOH

Movies\ester base hydrolysis.mov

5.17 Sulfur analogs of esters

• E.g., Acetyl coA

5.18 Polyesters…..skip

5.19 Acid anhydrides

Acid anhydrides can be organic or inorganic or both

O

O O

1. Organic

2. Inorganic O PO

O

O

P O

O

O

3. Organic and inorganic

O

PO

OO

O

P

O

O

O

O

OH

1,3-bisphosphoglycerate

Mixed anhydride bond

Phosphate ester bond

Glyceric acid

5.20 Esters of inorganic acids

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