Transcript
Page 1: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Chapter 15:Carboxylic Acids and Esters

Page 2: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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CARBOXYLIC ACIDS• The functional group of carboxylic acids is the carboxyl

group.

• Many carboxylic acids have common names.

Page 3: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Page 4: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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CARBOXYLIC ACIDS IUPAC NOMENCLATURE• Find the longest carbon chain that contains the –COOH

group.• Drop the –e from the end of the hydrocarbon name and

substitute –oic acid.• Number the longest chain. Carbon number 1 is the

carboxyl carbon.

• Name and number other substituents.

Examples:

Page 5: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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• Aromatic acid names are derived from the parent compound, benzoic acid.

Example:

Page 6: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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PHYSICAL PROPERTIES OF CARBOXYLIC ACIDS• Low molecular weight carboxylic acids are liquids at room

temperature and have characteristically sharp or unpleasant odors.

• The –COOH group is very polar. Hydrogen bonding between –COOH groups creates dimers (two identical molecules bonded together).

• This gives carboxylic acids high boiling points (greater than alcohols).

Page 7: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Page 8: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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PHYSICAL PROPERTIES, cont.• –COOH groups can hydrogen bond with water. If the

hydrophobic –R group is not too large, carboxylic acids are very water soluble.

Page 9: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ACIDITY OF CARBOXYLIC ACIDS• Carboxylic acids behave as weak acids (low dissociation),

forming carboxylate ions in water.

Example:

Page 10: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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SALTS OF CARBOXYLIC ACIDS• Carboxylic acids react readily with strong bases (NaOH,

KOH) to form salts.

Page 11: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Examples:

Page 12: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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SALTS, cont.• To name a carboxylic acid salt, name the metal ion first

and change the –ic ending of the acid name to –ate.

Example:

Page 13: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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USEFUL CARBOXYLIC ACID SALTS• Na+ and K+ salts of long-chain acids are used as soaps

(sodium stearate).• Calcium and sodium propanoate are used as preservatives

in bakery products.• Sodium benzoate is a food preservative used in ketchup

and soda pop.

• Zinc 10-undecylenate is used to treat athlete’s foot.

Page 14: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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CARBOXYLIC ESTERS• The ester functional group with the ester linkage between

the carbonyl carbon and the oxygen atom:

Page 15: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTERS, cont.• Esterification is the process of forming an ester linkage

between a carboxylic acid and an alcohol.

Page 16: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Examples:

Page 17: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTERS, cont.• Because of the reversible nature of the esterification

reaction, carboxylic acid chlorides and carboxylic acid anhydrides are used instead of the carboxylic acid to obtain higher product (ester) yields.

Page 18: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTERS, cont.

Examples:

Page 19: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTERS, cont.

Specific Examples:

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ESTERS, cont.• Polyesters – polymers made by the esterification process.

An example of condensation polymerization.

n(monomers) (polymer)n + nH2O

Page 21: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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NAMING ESTERS• The first word of the name of an ester is the name of the

alkyl or aromatic group (R') contributed by the alcohol.

• The second word is the carboxylic acid name, with the –ic acid ending changed to –ate.

Page 22: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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NAMING ESTERS, cont.

Examples:

Click here to play Coached Problem

Click here to play Coached Problem

Page 23: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTER REACTIONS• Ester hydrolysis – the reverse of esterification

Page 24: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Specific Examples:

Page 25: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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ESTER REACTIONS, cont.• Saponification – similar to hydrolysis, but carried out with a

strong base to produce a carboxylic acid salt

Page 26: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Examples:

Click here to play Coached Problem

Page 27: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Page 28: 1 Chapter 15: Carboxylic Acids and Esters. 2 CARBOXYLIC ACIDS The functional group of carboxylic acids is the carboxyl group. Many carboxylic acids have

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Esters of Inorganic Acids• Esters can be formed by reacting alcohols with inorganic

acids such as sulfuric, nitric, or phosphoric acids

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INORGANIC ACID ESTERS, cont.• Because phosphoric acid has three –OH groups, it can

form mono-, di-, and triesters.

• Mono- and diesters are very important biologically.

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PHOSPHORIC ANHYDRIDES • Phosphate esters that have two or three phosphate groups

linked together:

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• Adenosine diphosphate (ADP) and adenosine triphosphate (ATP) are two phosphoric anhydrides of great biological importance. In each case, the R group is adenosine.


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