Carboxylic Acids and Their Derivatives

By:

Dr. Shatha Alaqeel

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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 –COOH

The general formula of a carboxylic acid is R-COOH or Ar-COOH

Nomenclature of Carboxylic Acid

General formula: R-COOH or Ar-COOH

In the IUPAC: Find the longest continuous carbon chain contains the COOH group to Find the longest continuous carbon chain contains the COOH group to get the root name of the parent hydrocarbon, then replace the ending get the root name of the parent hydrocarbon, then replace the ending -e-e by the suffix by the suffix –oic –oic acidacid..

Number the chain starting with the carbon of COOH group as C-1Number 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 If there are substituents identify their names, positions and list them as prefixes in alphabetical orderalphabetical order..

common Formic acid Acetic acid Propionic acid Butyric acid Valeric acid

IUPAC Methanoic acid Ethanoic acid Propanoic acid Butanoic acid Pentanoic acid

C

O

H OH CH3 C

O

OH C2H5 C

O

OH C3H7 C

O

OH C4H9 C

O

OH

In common : the position of the carbons present on the acid chain, are located by the Greek letters αα indicating the carbon indicating the carbon

atom next to COOH group (C2), atom next to COOH group (C2), ββ (C3), (C3), γγ (C4), (C4), δδ (C5), etc (C5), etc. .

In IUPAC: The carboxylic carbon is numbered 1.

common: -- Dimethyl butyric acid

IUPAC: 2,3-Dimethyl butanoic acid

CH3

COOH

CH3

CH3

5

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

COOH

HOOC

COOH

HOOC

Cyclopropane Cyclobutane Cyclopentane Cyclohexane Carboxylic acid Carboxylic acid Carboxylic acid Carboxylic acid

COOHCOOH

COOHCOOH

NH2Cl

2-Isopropyl-cyclobutanecarboxylic acid

3-Amino-cyclohexanecarboxylic acid

Br

2-Bromo-4-chloro-cyclopentanecarboxylic acid

Cyclopropanecarboxylic acidCH(CH3)2

commoncommon Benzoic acid Salicylic acid

IUPACIUPAC Benzene carboxylic acid 2-Hydroxybenzenecarboxylic acid

commoncommon Phethalic acid Terephtalic acid

IUPACIUPAC Benzene-1,2-dicarboxylic acid Benzene-1,4-dicarboxylic acid

COOH COOH

OH

COOH

COOH

COOH

COOH

Some aromatic compounds have common names accepted by the Some aromatic compounds have common names accepted by the IUPACIUPAC also they also they Can be named aCan be named as benzene carboxylic acidss benzene carboxylic acids

Physical Properties OF Carboxylic Acids

SolubilitySolubility

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

Smaller carboxylic acids (1 to 4 carbons) are soluble in waterSmaller carboxylic acids (1 to 4 carbons) are soluble in water

Whereas the solubility of bigger carboxylic acids decrease with sizeWhereas the solubility of bigger carboxylic acids decrease with size

Aromatic acids are insoluble in waterAromatic acids are insoluble in water

RC

O

O

H

O

H

H

H

O

H

H-Bonds

The boiling points of carboxylic acids indicate a greater degree than alcohols

This is due to carboxylic acids usually exist as dimeric pairs by forming two This is due to carboxylic acids usually exist as dimeric pairs by forming two intramolecular hydrogen bonds in nonpolar media intramolecular hydrogen bonds in nonpolar media

Boiling Boiling PointsPoints

H3C CO

O H O

H OC CH3

Hydrogen bond

Carboxylic acids are the most acidic simple organic compounds (they are Carboxylic acids are the most acidic simple organic compounds (they are stronger acids by over ten powers of ten compared to alcohols of comparable stronger acids by over ten powers of ten compared to alcohols of comparable weights); also they are more acidic than phenols weights); also they are more acidic than phenols

However, they are weak acids compared to inorganic acids (HCl or HHowever, they are weak acids compared to inorganic acids (HCl or H22SOSO44))

Adjacent Adjacent electron withdrawing electron withdrawing substituents substituents nearnear the carboxyl group the carboxyl group increase increase the the acidity acidity

Whereas Whereas electron donating electron donating substituents substituents decrease decrease the aciditythe acidity. .

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

group)group)

Cl3CCOOH > Cl2CHCOOH > ClCH2COOH > CH3COOH > (OCH3)CH2COOH

) )number of e.w.g. and e.d. gnumber of e.w.g. and e.d. g(.(.

CH3CH2CH2CH(Cl)COOH > CH3CH2CH(Cl)CH2COOH > CH3CH(Cl)CH2CH2COOH > CH2(Cl)CH2CH2CH2COOH ( position of e.w.g. ( position of e.w.g.

relative to COOH group)relative to COOH group)> > > >

COOH

NO2O2N

COOH

NO2

COOH COOH COOH

Acidity And Acid Strength

11 - -Oxidation Of Primary AlcoholsOxidation Of Primary Alcohols

22 - -Oxidation Of Alkyl BenzenesOxidation Of Alkyl Benzenes

Preparation Of Carboxylic acids

33 - -Carbonation Of Grignard ReagentsCarbonation Of Grignard Reagents

44 - -Hydrolysis Of NitrilesHydrolysis Of Nitriles

H2O

H2O

Reactions of Carboxylic Acids1- Salts Formation

RCOOH

KOH or NaOHRCOO

-K

+ or Na

+ + H2O

NaHCO3 RCOO-Na

+

+ CO2 H2O+

NH3 RCOO-NH4

+

COOH

OH

+

+

NaHCO3

NaHCO3

COO-Na

+

N . R

Sodium Benzoate

2- Substitution of hydroxyl group

RCOOH

R'OH / H+

NH3

SOCl2

1) PCl52) R''COO

-Na

+

RCOOR'

RCONH2

RCOCl

RCOOCOR"

Ester

Amide

Acid Chloride

Anhydride

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 anhydride

1-Nomenclature of acid chloride�ٌ Replacing the –ic acid ending of the parent acid by –yl chloride:

Ethanoyl chloride Benzoyl chloride Acetyl chloride

CH3 C

O

Cl

C

O

Cl

2- Nomenclature of esters

The alkyl group (R’) is named first followed by the name of the parent acid with the ending –ate in place –ic acid:

Ethyl ethanoate Methyl benzoate Ethyl acetate

CH3 C

O

OC2H5

C

O

OCH3

3- Nomenclature of amide

Replacing the ending oic acid of the parent acid’s by amide

Ethanamide Benzamide

Acetamide

N,N-Dimethylmethamide N-Ethyl-N-methylbenzamide

N,N-Dimethylformamide

CH3 C

O

NH2

C

O

NH2

H C

O

NCH3

CH3

C

O

NCH3

CH3

4- Nomenclature of anhydride

An anhydride is named by replacing the word acid by anhydride.

Ethanoic anhydride Benzoic anhydide Succinic anhydride

CH3 C

O

O C

O

CH3C

O

O C

O

O OO

Reaction of Esters

R C

O

OR'

+ OH2 R C

O

OH

+ R'OHH

+

R C

O

OR'

+ R''OH R C

O

OR"

+ R'OHH

+

R C

O

OR'

+ NH3 R C

O

NH2

+ R'OHH

+

R C

O

OR'

R CH2 OH + R'OH1) LiAlH4

2) H3O+

R C

O

OR'

R C OH

R"

R"

+ R'OH1) Dry ether

2) H3O++ 2 R"MgX

Acid Chlorides: Reactions

R C

O

Cl+

OH2 R C

O

OH

+ ClH

R'OH R C

O

OR'+ ClH

NH3 R C

O

NH2

+ ClH

NH2R' R C

O

NHR'

+ ClH

R C

O

1) LiAlH4

2) H3O+ R CH2OH

AlCl3 + ClH

Acid anhydride: Reactions

+

OH2 R C

O

OH

+ R'COOH

R'OH R C

O

OR'+ R'COOH

NH3 R C

O

NH2

+ R'COOH

NH2R' R C

O

NHR'

+ R'COOH

R C

O

1) LiAlH4

2) H3O+ R CH2OH

AlCl3 + R'COOH

R C

O

O C

O

R'

+ R'CH2OH

Reactions of Amides

R C

O

NH2

H3O+

R C

O

OH+ NH3

R C

O

NH2

NaOH/ heatR C

O

ONa+ NH3

R C

O

NH2

1) LiAlH4R CH2 NH2

2) H3O+

R C

O

NHR'

1) LiAlH4R CH2 NHR'

2) H3O+

R C

O

NH2

P2O5R C N

- H2O

R C

O

NH2

Br2 / NaOHR NH2

or NaOBr