1.6 Carboxylic Acids and Esters Learning Goals … … name and draw carboxylic acids … name and draw esters

Carboxylic Acids contain the carboxyl group located at the end of a parent chain General formula:   O R – C R-COOH OH name carboxylic acids by replacing the – e with – oic acid number chain so that the carboxyl group is at position #1

ethanoic acid (acetic acid) CH3 C OH II O ethanoic acid (acetic acid) CH3 CH3 – C – CH2 – C = 0 CH3 OH butanoic acid 3,3-dimethyl 4-methylpentanoic acid

benzoic acid C O H2C OH phenylethanoic acid

Properties of Carboxylic acids polar and weakly acidic hydrogen bonding can occur between molecules and with water very high boiling points due to strong Hydrogen bonds often have unpleasant odours the –OH group does NOT behave like the basic hydroxide ion – only the H+ ion is lost in solution to form an acid

Esters General formula: R – C R-COOR’ O R – C O II II OR’ OR’   R – C R-COOR’   R – C O O II II OR’ OR’ main chain alkyl group To name an ester: Name the alkyl group attached to the O, indicate position # Name the parent chain which includes the C=O group, replacing the ending with –oate Put the 2 names together (but as separate words)

O II CH3CH2CH2C-O-CH2CH3 ethyl butanoate O II 1-propyl methanoate C-O-CH2CH2CH3 H Note: main chain does not have to be the longest chain CH3CH2COOCH2(CH3)CH2CH3 II O CH3CH2C-O-CH2CH2CH3 CH3 2-butyl propanoate

Properties of Esters 2-butyl methylpropanoate polar low boiling points ester groups are found in fats and oils often produce pleasant odours and tastes, such as in fruits. As a result, they are often used for perfumes and artificial flavours

HOMEWORK Self Check How prepared am I to start my homework? Can I … … name and draw carboxylic acids … name and draw esters HOMEWORK p48 #1, 2 p50 #1, 2 p55 #1,2