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

Transcription

1 Chapter 16

2 Carboxylic Acids A carboxylic acid contains a a hydroxyl group ( OH) attached to a carboxyl group, which is a carbonyl group Pearson, Education Inc.

3 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.

4 Common Names of Carboxylic Acids Many 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.

5 Guide to Naming Carboxylic Acids

6 IUPAC Names for Carboxylic Acids Give the IUPAC and common name for the following carboxylic acid.

7 IUPAC Names for Carboxylic Acids Give the IUPAC and common name for each carboxylic acid. Analyze the Problem. Functional Group carboxylic acid IUPAC Naming Change the -e of the alkane name to -oic acid and count from carbon 1 of the carboxyl group for any substituents. Name Alkanoic acid

8 IUPAC Names for Carboxylic Acids Give the IUPAC and common name for each carboxylic acid. Step 1 Identify the longest carbon chain and replace the -e in the corresponding alkane name with -oic acid. butanoic acid

9 IUPAC Names for Carboxylic Acids Give the IUPAC and common name for each carboxylic acid. Step 2 Give the location and name of each substituent by counting the carboxyl carbon as 1.

10 Learning Check Give the IUPAC and common names for each of the following. A. B.

11 Solution Give the IUPAC and common names for each of the following. A. ethanoic acid (acetic acid) B. 2-Methylpropanoic acid ( -methylpropionic acid)

12 Learning Check Give the IUPAC and common names for the following. A. B Pearson Education, Inc. Chapter 15, Section 2 12

13 Solution Give the IUPAC and common names for the following. A. propanoic acid (propionic acid) B. 3-Methylbutanoic acid ( -methylbutyric acid) 2013 Pearson Education, Inc. Chapter 15, Section 2 13

14 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) Pearson Education, Inc.

15 Polarity of Carboxylic Acids Carboxylic acids are strongly polar. have two polar groups. hydroxyl ( OH) and carbonyl (C O)

16 Solubility in Water Carboxylic acids form hydrogen bonds with many water molecules. with 1 to 4 carbon atoms are very soluble in water. Water molecules

17 Esters Esters 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 Pearson Education, Inc. Chapter 15, Section 2 17

18 Esterification 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

19 Acetylsalicylic Acid Aspirin is 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 Pearson Education, Inc. Chapter 15, Section 2 19

20 Acetylsalicylic Acid In 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 Pearson Education, Inc. Chapter 15, Section 2 20

21 Guide to Naming Esters

22 Naming Esters The name of an ester contains the names of the alkyl group from the alcohol, and the carbon chain from the acid with -ate ending.

23 Learning Check Give the IUPAC name of the following ester, responsible for the flavor and odor of pears.

24 Solution Give the IUPAC and common name of the following ester, responsible for the flavor and odor of pears. Step 1 Write the name of the carbon chain from the alcohol as an alkyl group. propyl from 1-propanol

25 Solution Give the IUPAC and common name of the following ester, responsible for the flavor and odor of pears. Step 2 Change the -ic acid of the acid name to -ate. Ethanoate Propyl ethanoate (IUPAC name)

26 Learning Check Name the following esters.

27 Solution Name the following esters. Step 1 Write the name of the carbon chain from the alcohol as an alkyl group. A. methyl B. ethyl

28 Solution Name the following esters. Step 2 Change the -ic acid of the acid name to -ate. A. Butanoic acid becomes butanoate Methyl butanoate

29 Solution Name the following esters. Step 2 Change the -ic acid of the acid name to -ate. B. Propanoic acid becomes propanoate. Ethyl propanoate

30 Learning Check Draw the condensed structural formula of the following ester. Ethyl pentanoate

31 Solution Draw the condensed structural formula of the following ester. Ethyl pentanoate

32 Acid Hydrolysis of Esters In acid hydrolysis, an ester reacts with water to produce a carboxylic acid and an alcohol. a strong acid catalyst is required.

33 Learning Check Aspirin stored for a long time may undergo hydrolysis in the presence of water and heat. What will be the products of this reaction?

34 Solution Aspirin stored for a long time may undergo hydrolysis in the presence of water and heat. What will be the products of this reaction? To write the hydrolysis products, separate the compound at the ester bond. Complete the formula of the carboxylic acid by adding OH (from water) to the carbonyl group and H (from water) to the alcohol.

35 Base Hydrolysis (Saponification) Base hydrolysis (also called saponification) is the reaction of an ester with a strong base. produces the salt of the carboxylic acid and an alcohol.