The Foundations of Chemistry

1080 CHAPTER 27: Organic Chemistry I: Formulas, Names, and Properties

The fragment is derived from acetic acid, the parent acid; the OXCH 2 CH 3

fragment is derived from ethanol, the parent alcohol. Models of ethyl acetate, an ester,

are shown in Figure 27-18.

Esters are nearly always called by their common names. These consist of, first, the

name of the alkyl group in the alcohol, and then the name of the anion derived from the

acid.

Because of their inability to form hydrogen bonds, esters tend to be liquids with boiling

points much lower than those of carboxylic acids of similar molecular weights.

Most simple esters are pleasant-smelling substances. They are responsible for the flavors

and fragrances of most fruits and flowers and many of the artificial fruit flavorings that

are used in cakes, candies, and ice cream (Table 27-13). Esters of low molecular weight

are excellent solvents for nonpolar compounds. Ethyl acetate is an excellent solvent that

gives many nail polish removers their characteristic odor.

Fats(solids) and oils(liquids) are esters of glycerol and aliphatic acids of high molec-

ular weight. “Fatty acids” are all organic acids whose esters occur in fats and oils. Fats and

oils have the general formula

C OCH 3

O

methyl benzoate

CH 3 C O

O

phenyl acetate

CH 3 CH 2 C OC(CH 3 ) 3

O

t-butyl propionate

C

O

CH 3

TABLE 27-13 Some Common Esters

Ester Formula Odor of

isoamyl acetate CH 3 COOC 5 H 11 bananas

ethyl butyrate C 3 H 7 COOC 2 H 5 pineapples

amyl butyrate C 3 H 7 COOC 5 H 11 apricots

octyl acetate CH 3 COOC 8 H 17 oranges

isoamyl isovalerate C 4 H 9 COOC 5 H 11 apples

methyl salicylate C 6 H 4 (OH)(COOCH 3 ) oil of wintergreen

methyl anthranilate C 6 H 4 (NH 2 )(COOCH 3 ) grapes

See the Saunders Interactive
General Chemistry CD-ROM,
Screen 11.7, Fats and Oils.

Figure 27-18 Models of ethyl acetate, CH 3 C O CH 2 CH 3 ,an ester.

O

Apple blossoms.