Carboxilic acids, amides and esters

CARBOXILIC ACIDS

• Carboxylic acids are compounds which contain a carboxy group -COOH group. 

• General formula R-COOH or

• The rule is that functions assume their distinct identity when separated by –CH2– groups.

• Thus, the carbonyl, C=O, and hydroxy, OH, of a carboxylic acid, RCOOH, are part of a single function and are NOT "alcohol-plus-ketone":

Nomenclature of Carboxylic Acids•As with aldehydes, the carboxyl group must

be located at the end of a carbon chain.• In the IUPAC system of nomenclature the

carboxyl carbon is designated #1, and other substituents are located and named accordingly.

•The characteristic IUPAC suffix for a carboxyl group is "oic acid", and care must be taken not to confuse this systematic nomenclature with the similar common system.

Examples

Name the followingA) B)

C) D)

Draw the following and give the IUPAC name

•Formic acid

•Malonic Acid

•Acetic acid

•Propionic acid

AMIDES

•Amides are amine derivatives of carboxylic acids.derived from carboxylic acids.

•A carboxylic acid contains the -COOH group, and in an amide the -OH part of that group is replaced by an -NH2 group.

•Amides contain the -CONH2 group.

•General Formula R-CONH2 or

Nomelnclature

HCONH2 methanamide

CH3CONH2 ethanamide

CH3CH2CONH2 propanamide

Notice that in each case, the name is derived from the acid by replacing the "oic acid" ending by "amide".

Nomenclature

•If the chain was branched, the carbon in the -CONH2 group counts as the number 1 carbon atom. For example:

ESTERS

•The simple esters tend to have pleasant odors.  

•The characteristic flavors and fragrances of flowers and fruits are due to compounds with the ester functional group.

•General Formula R-COO-R’ or R-CO-OR’ or

Nomenclature•Esters are produced when carboxylic

acids (COOH) are heated with alcohols (OH) in the presence of an acid catalyst.

•An ester name has two parts - the part that comes from the acid ending ““ateate” ” and the part that shows the alkyl group coming fro the allcohol ending “ylyl”

Nomenclature

•Notice that the ester is named the opposite way around from the way the formula is written.

•The "ethanoate" bit comes from ethanoic acid. The "ethyl" bit comes from the ethyl group on the end.

Examples

Name

Draw

Answers

Making estersThe chemistry of the reaction•Esters are produced when carboxylic

acids (COOH) are heated with alcohols (OH) in the presence of an acid catalyst. The catalyst is usually concentrated sulphuric acid.

•The equation for the reaction between an acid RCOOH and an alcohol R'OH (where R and R' can be the same or different) is:

•So, for example, if you were making ethyl ethanoate from ethanoic acid and ethanol, the equation would be:

Doing the reactions (Laboratory)On a test tube scale•Carboxylic acids and alcohols are often

warmed together in the presence of a few drops of concentrated sulphuric acid in order to observe the smell of the esters formed.