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Dr Nahed Elsayed

Learning ObjectivesLearning Objectives

Chapter nine introduces carboxylic acids and their derivatives. The chemistry is very Chapter nine introduces carboxylic acids and their derivatives. The chemistry is very similar to that of aldehydes and ketones because of the presence of the carbonyl group . similar to that of aldehydes and ketones because of the presence of the carbonyl group . The main topics in this chapter that the students should know and understand include:The main topics in this chapter that the students should know and understand include:

The structure of carboxylic acidsThe structure of carboxylic acidsThe common and IUPAC nomenclature of The common and IUPAC nomenclature of carboxylic acidscarboxylic acidsThe physical properties of The physical properties of carboxylic acidscarboxylic acidsThe Factors affecting acidity of carboxylic acids.The Factors affecting acidity of carboxylic acids.The different ways to make The different ways to make carboxylic acidscarboxylic acidsSalt formation reactions of carboxylic acidsSalt formation reactions of carboxylic acidsThe nucleophilic substitution reactions at the carbonyl carbon and the specific The nucleophilic substitution reactions at the carbonyl carbon and the specific products formed in each case.products formed in each case. The chemistry of carboxylic acid derivativesThe chemistry of carboxylic acid derivatives

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Structure Of Carboxylic AcidsStructure Of Carboxylic Acids

Carboxylic acids are organic acids contain one or more carboxyl group

A carboxyl group is made up of a carbonyl (C=O) group and a hydroxyl (O-H) group

It is often written in condensed form as –CO2H or –COOHCarboxylic acids are classified as aliphatic R-COOH or aromatic Ar-COOH depending on the group bonded to the carboxylic group.The simplest aliphatic acid is formic acid R= HThe fatty acid is long chain aliphatic acids CH3-(CH2)16-COOH

Nomenclature Of Carboxylic AcidsNomenclature Of Carboxylic Acids

Some carboxylic acids are called after characteristic properties or their origin.

Formula Common name origin of nameHCOOH formic acid Latin for antCH3COOH acetic acid Latin for vinegarCH3CH2COOH propionic acid Greek for milkCH3 (CH2)2COOH butyric acid Latin for butterCH3 (CH2)3COOH valeric acid valerian root

Common NomenclatureCommon Nomenclature

COOHCC

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The positions of the carbons present on the acid chain, are located by the Greek letters α indicating the carbon atom next to COOH group (C2), β (C3), etc.

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Some aromatic acids have common names

Benzoic acid Salicylic acid

COOH COOH

OH

HOOCCOOH

Succinic acid

Example of dicarboxylic acids

IUPAC NomenclatureIUPAC NomenclatureFind the longest continuous carbon chain contains the COOH group to get the root name of the parent hydrocarbon, then replace the ending -e by the suffix –oic acid. Number the chain starting with the carbon of COOH group as C-1 If there are substituents identify their names, positions and list them as prefixes in alphabetical order.

Examples: Examples: (CH(CH33))22CH - CH(CHCH - CH(CH33) - CH) - CH22 - CH - CH22 - COOH - COOH is called 4,5-Dimethylhexanoic acid

C4H9

O

OHC3H7

O

OH

Butanoic acid Pentanoic acid

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Cyclic compounds containing one or more COOH groups attached to the ring are named by identifying the name of the ring followed by the word carboxylic acid or dicarboxylic acids etc. The carbon atom bearing the carboxylic group is numbered 1 and the substituents are numbered relative to it.

COOHCOOH

COOHCOOH

NH2Cl

2-Isopropyl-cyclobutanecarboxylic acid

3-Amino-cyclohexanecarboxylic acid

Br

2-Bromo-4-chloro-cyclopentanecarboxylic acid

Cyclopropanecarboxylic acidCH(CH3)2

Br

OH

O

OH

NH2

OH

O

HOOCCOOH

1,4-Butandioic acid

3-Bromo-2-hydroxy-4-hexenoic acid

3-Aminobutanoic acid

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Some aromatic compounds have common names accepted by the IUPAC also they can be named as benzene carboxylic acids

Benzene carboxylic acid Benzene-1,2-dicarboxylic acid2-Hydroxybenzene carboxylic acid

COOH COOH COOH

OH COOH

Physical Properties OF Carboxylic Acids

SolubilitySolubility

Carboxylic acids are polar, they can form hydrogen bonds with water molecules

The first four aliphatic acids are completely miscible in water. Higher members are less soluble Aromatic acids are insoluble in water

RC

O

O

H

O

H

H

H

O

H

H-Bonds

Carboxylic acids have exceptionally high boiling points than alcohols and aldehydes, because their dimeric structures. of identical relative molecular masses, For example:

M.F. M.W bp / °C

Propanol C3H8O 60.01 97.2

Ethanoic acid C2H4O2 60.05 118

Boiling Boiling PointsPoints

Hydrogen-bonded acid dimer

R C

O

OH

C R

O

HO

Carboxylic acids are stronger acids compared to alcohols and phenolscompared to alcohols and phenols Electron withdrawing substituents substituents nearnear the carboxyl group the carboxyl group increase the aciditythe acidity Whereas Whereas electron donating substituents substituents decrease the acidity .the acidity .

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HCOOHHCOOH >> CHCH33COOHCOOH >> CHCH33CHCH22COOHCOOH >> CHCH33CHCH22CHCH22CHCH22COOHCOOH ( size of ( size of

R group)R group)

Cl3CCOOH > Cl2CHCOOH > ClCH2COOH > CH3COOH ( number of ( number of

e.w.g.)e.w.g.)

> > > >COOH

NO2O2N

COOH

NO2

COOH COOH COOH

Acid Strength

1- Oxidation Of Primary Alcohols1- Oxidation Of Primary Alcohols

2- Oxidation Of Alkyl Benzenes2- Oxidation Of Alkyl Benzenes

Preparation Of Carboxylic acids

K2Cr2O7/H+

CH2OH R COHor KMnO4/heat

O

R

Primary alcoholcarboxylic acid

K2Cr2O7/H+

CH R COHor KMnO4/heat

O

R

aldehyde carboxylic acid

O

3- Carbonation Of Grignard Reagents3- Carbonation Of Grignard Reagents

4- Hydrolysis Of Nitriles4- Hydrolysis Of Nitriles

or i) KOH ii) H3O+

Reactions Of Carboxylic Acids1- Salts Formation

COOH

NaHCO3

COO Na

Sodium benzoate

+ CO2 + H2O

2- Substitution Of Hydroxyl Group2- Substitution Of Hydroxyl Group

R L

O

+ Nu

R Nu

O

+ L

General EquationGeneral Equation

Carboxylic Acid Derivatives

R C

O

Cl

R C

O

OR'

R C

O

N

R C

O

O C

O

R'

Acid Chloride Ester Amide Acid Acid Chloride Ester Amide Acid anhydrideanhydride

The derivatives of carboxylic acids are compounds in which the -OH of carboxylic acid is replaced by nucleopile (-X for acid halide, -OR for ester, -NH2, -NHR, -NR2 for amids, -OOCR for anhydride).

Carboxylic acids derivatives can converted to carboxylic acids by simple acidic or basic hydrolysis.

Carboxylic Acid Derivatives1-Nomenclature Of Acid Chlorides

Replace Replace the -ic acid ending in the name of the parent acid by –yl chloride

IUPAC: Ethanoyl chloride BenzoylchlorideEthanoyl chloride Benzoylchloride Propanoyl Propanoyl chloridechlorideCommon : Acetyl chlorideAcetyl chloride

H3C

Cl

O

Cl

O

CH3CH2 C

O

Cl

2- Nomenclature of esters The alkyl group (R’) is written first followed by the name of the parent acid with replacing of the ending –ic acid by –ate :

(IUPAC) Ethyl ethanoate Methyl benzoate (common) Ethyl acetate

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CH3CH2 C

O

OCH3

HOO

O(IUPAC) Methyl propanoate Isopropyl-4-hydroxy-5-methyl-5- hexenoate

3- Nomenclature of amideReplace the ending oic acid of the parent acid’s by the word amideIf there is R group on the nitrogen atom, it is listed first and

designated with –N

(IUPAC) Ethanamide Benzamide N-Methylpropanamide(common) Acetamide N-

Methylpropionamide

(IUPAC) N,N-Dimethylmethamide N-Ethyl-N-methylbenzamide

(Common) N,N-Dimethylformamide145 Chem.19

CH3CH2 C

O

NHCH3

4- Nomenclature of anhydrideAn anhydride is named by replacing the word acid in the corresponding acid by the word anhydride. Due to it is obtained from corresponding

acid by dehydration as shown in the following equation:

(IUPAC) Ethanoic anhydride Benzoic anhydride Butandioic anhydride

(Common) Acetic anhydride Succinic anhydride

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OH

O

OH

O

O

O

O

heat

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Preparation of acid derivatives from acid chloride

Cl

O

CH3OH

CH3NH2

ONa

O

OCH3

O

NH-CH3

O

O

O O

Reaction of Derivatives of carboxylic acid

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R

O

O

R

O

O

O

R

R

O

NH2

R

O

Cl

H3O+

H3O+

H3O+

H3O+

or eq NaOH/H3O+

R

O

OH

On hydrolysis (reaction with H2O/ H+) all carboxylic acid derivatives convert to carboxylic acid.

QuestionsQuestions

MgBr

A) B) C) D)

COOH CH2OH COOH

COOH3

1- Reaction of with CO2 under heat and pressure gives:

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2- Oxidation of C6H5CH2OH with KMnO4 gives:

COOHCOOH

CH2OH

OH

CH2OH

NO2

A) B) c) D)

CH3CH2 C

O

NCH3

CH3

4- The common name of this compound is?

A) N,N-Dimethylacetamide B) N,N-Dimethyl propanamide

C) N,N-Dimethylpropionamide D) N,N-Dimethylbutanamide

5- Acid halide react with ammonia to give?

A) Amines B)Amides C) Phenols D) Alcohols

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3- The most acidic compound is?

CH3CH2CH2COOH

CH3CHCH2COOH

Cl

CH3CH2CH

Cl

COOH

CH3CH2HC2COOH

A) B)

C) D)

Questions?