Carboxylic acids

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Slide 1

Alcohols revisited (and ethers)

and going further .

13.3 Carboxylic acids and their derivatives

Slide 2

Alcohols

homologous series containing the OH hydroxyl group.

all names end in ol eg methanol, ethanol etc.

isomers are possible for alcohols containing 3 or more carbons.

label position of OH group so that it has the lowest number possible.

polyhydric alcohols contain more than one OH group eg propane- 1,2,3,triol

OH groups attached to benzene rings are called phenols.

Slide 3

Physical properties of alcohols

Molecules are polar, in the O-H bond, O is - and H is +

Molecules have attractive forces between the molecules called hydrogen bonds, not as strong as covalent bonds.

Higher boiling point than corresponding alkanes.

Hydrogen bonds form between alcohol and water molecules therefore they are miscible / soluble.

Long chain alcohols are less soluble.

Slide 4

Ethers

General formula R-O-R’

O-R’ alkoxy group substituted for H eg

CH3-CH2-CH2-O-CH3 methoxypropane

Longer hydrocarbon chain is parent alkane for naming.

Slide 5

Physical properties of ethers

Molecules only slightly polar.

No hydrogen on the oxygen atoms to form hydrogen bonds – only weak forces of attraction between molecules.

Boiling points similar to corresponding alkane.

Lower ethers, very volatile, highly flammable.

Only slightly soluble in water, mix well with other non-polar solvents eg alkanes. (Like dissolves like).

Slide 6

Carboxylic acid structure

Formula -COOH

Oxygen atoms not joined together.

General formula when rest of structure is an alkyl group R-COOH.

Carboxyl group

Slide 7

Naming carboxylic acids

Alkanes

CH4 methane

CH3 -CH3 ethane

CH3-CH2-CH3 propane.

CH3-CH(CH3)-CH2-CH3 2-methylbutane

Carboxylic acids

H-COOH methanoic acid

CH3 -COOH ethanoic acid

CH3-CH2-COOH propanoic acid

CH3-CH(CH3)-CH2-COOH 3-methylbutanoic acid

Slide 8

Naming more complex examples

Two carboxylic acid groups -dioic

Carboxyl group can be attached to a benzene ring eg benzenecarboxylic acid.

ethanedioic acid

propanedioic acid

benzenecarboxylic acid (benzoic acid)