Carboxylic Acids

A carboxylic acid contains a a hydroxyl group (–OH) attached to a carboxyl group, which is a carbonyl group .

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IUPAC Names of Carboxylic Acids

IUPAC Names of Carboxylic Acids

The name of the carboxylic acid of benzene, is benzoic acid. The carbon in the carbonyl group is bonded to . carbon 1 in the benzene ring. The ring is numbered to give the lowest possible numbers for any substituents. The prefixes ortho, meta, and para may be used to show the position of one other substituent.

IUPAC Names of Carboxylic Acids

The prefixes ortho, meta, and para may be used to show the position of one other substituent. Insert diagram of benzoic acid, 4-aminobenzoic acid and 3,4-dichlorobenzoic acid bottom pg 571 with labels.

Common Names of Carboxylic AcidsMany carboxylic acids are still named by their

common names that include prefixes, form, acet, propion, butyr.

When using the common names, the Greek letters alpha (), beta (), and gamma () are assigned to the carbons adjacent to the carboxyl carbon.

Formic Acid

A red ant sting contains formic acid that irritates the skin.

H

C

O

OH

Guide to Naming Carboxylic Acids

IUPAC Names for Carboxylic Acids

Give the IUPAC and common name for each carboxylic acid.

IUPAC Names for Carboxylic Acids

Step 1 Identify the longest carbon chain and add “anoic acid” to the end of the base name (for the straight chain acids).

butanoic acid benzoic acid

IUPAC Names for Carboxylic Acids

Step 2 Give the location and name of each substituent by counting the carboxyl carbon as 1.

a. 2-methylbutanoic acid b. 3-chlorobenzoic acid

2-methylbutyric acid meta-chlorobenzoic acid

Alpha Hydroxy Acids

Alpha hydroxy acids (AHAs)

occur naturally in . fruit, milk, and . sugar cane. are used in skin . care products.

Learning Check

Give the IUPAC and common names for each of the following.

A.

B.

C.

A.

B.

C.

Solution

2-Bromobenzoic acid(o-bromobenzoic acid)

2-Methylpropanoic acid

ethanoic acid (acetic acid)

Learning Check

Give the IUPAC and common names for the following.

A.

B.

C.

Solution Give the IUPAC and common names for the

following.

A.

B.

C.

propanoic acid(propionic acid)

3-Methylbutanoic acid(methylbutyric acid)

3-Bromobenzoic acid(m-bromobenzoic acid)

Preparation of Carboxylic Acids

Carboxylic acids are prepared by oxidizing primary alcohols or aldehydes.from the oxidation of ethanol, which

produces ethanoic acid (acetic acid).

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Learning Check

Which alcohol would be used to prepare the following?

A. butanoic acid

B. propanoic acid

Solution

(it is the alcohol with the same number of carbons!)

A.

B.

EstersEsters differ from carboxylic acids by the replacement of

H in the hydroxyl group with an alkyl group.are fragrant components of many fruits, such as

bananas, oranges, and strawberries.Yummy!

Esterification is the reaction of a carboxylic acid and alcohol in the presence of an acid catalyst to produce an ester.

Insert esterification reaction pg 580

Esterification

Acetylsalicylic AcidAspirinis used to relieve pain

and reduce inflammation.

is an ester of salicylic acid

and acetic acid.is derived from the

bark of a willow tree.

Acetylsalicylic AcidIn 1899, Bayer chemical company in Germany produced an ester of salicylic acid and acetic acid, called acetylsalicylic acid (aspirin) that was less irritating to the stomach than salicylic acid.

Methyl SalicylateOil of wintergreenis used to soothe sore muscles.has a pungent, minty odor.is an ester of salicylic acid and

methanol.

Esters in PlantsEsters give flowersand fruits their pleasant fragrances and flavors.

Naming Esters

The name of an ester contains the names ofthe alkyl group from the alcohol, andthe carbon chain from the acid with -ate

ending.

Example..

Give the IUPAC and common name of the following ester, responsible for the flavor and odor of pears. A hint is on the next slide…

Example..

Name the group on the oxygen first.

Example..

Name the group on the oxygen first: it is propyl.Now count the number of carbons including the carbonyl carbon that are in the other side of the ester:

O

O

Example..

there are two carbons in the “acid” side of the ester, so the base name uses 2…So this is propyl ethanoate.

O

O

Learning Check

Name the following ester. Hints are on the next few slides…

Learning Check

Remember, you want to count the number of carbons on the oxygen first. Since there is one, our “group” is __________

O

O

Learning Check

Remember, you want to count the number of carbons on the oxygen first. Since there is one, our “group” is methyl…

O

O

Learning Check

Now you want to focus on the base name which comes from the carbonyl side of the compound…

How many carbons are on this side?

O

O

Learning Check

How many carbons are on this side? 4So our base name is:

O

O

Learning Check

How many carbons are on this side? 4So our base name is: butanoate(that’s but for the 4 carbons and anoate

because it is an ester).

O

O

Learning Check

So the name of the compound is:Methyl butanoate.

O

O

Learning Check

Here is another ester to try to name...click through the next few slides to work through this stepwise.

Learning Check

Remember, we name the group on the oxygen first so the first part of the name is…

O

O

Learning Check

Remember, we name the group on the oxygen first so the first part of the name is…

ethyl

O

O

Learning Check

Now we look at the number of carbons in the “acid” side :

O

O

Learning Check

Now we look at the number of carbons in the “acid” side : 3

Since there are three, our base name is…Propanoate. Try to put the whole name together,

then check your answer on the next slide.

O

O

Learning Check

This is ethyl propanoate.

O

O

Learning Check

Draw the condensed structural formula of the following ester. Take it one step at a time…

What is the group on the oxygen?

A. Ethyl pentanoate

Learning Check

What is the group on the oxygen? The ethyl group is on the oxygen.

How many carbons are in the base structure?

A. Ethyl pentanoate

Learning Check

How many carbons are in the base structure?5 there are 5 carbons since the

base name is pent…Now draw in your ester. I usually start by

drawing the carbonyl with an oxygen attached…then add carbons where needed…

A. Ethyl pentanoate

O

O

Learning Check

A. Ethyl pentanoate

O

O

Learning Check

B. Propyl butyrate

So what is the group on the oxygen?

Learning Check

B. Propyl butyrate

So what is the group on the oxygen? Propyl (3 carbons)

How many carbons are in the base chain?

Learning Check

B. Propyl butyrate

So what is the group on the oxygen? Propyl (3 carbons)

How many carbons are in the base chain? 4

Learning Check

B. Propyl butyrate

The structure is…

O

O

Thank you for trying this online!I will see you on Wednesday, October 16th.Extra credit opportunities:October 21st: help with National Chemistry

Week activities…N-quad 11:15-1:15October 28th: help with Vietnamese Club

activity…N-2220 11:30-1:00October 31st: help with Halloween activity…

B/C-quad (I think)…11:15-3:00.