Carboxylic Acid

Among important examples are :

COOH

H H H

H

H

HH

OH

OH

HO

Cholic acid(a major component of human bile)

S SCOOHHOOC

NH2 NH2

Was first isolated by Van Veen and Hyman from the urine of the natives of Java who had eaten the djenkol bean and were suffering from poisoning.

Djenkolic acid

Carboxylic Acid

also, biological precursors of fats and other lipids :

CC

CH3(CH2)7 (CH2)7COOH

HH

Oleic acid

CC CC

(CH2)7COOHCH3(CH2)4 CH2

HHHH

Linoleic acid

Carboxylic Acid

This compounds contain the carboxylic group attached to :

O

C

OHH

A hydrogen

and

O

C

OHR

Alkyl group

or

O

C

OHAr

A ryl group

HCOOH

example

CH3COOH

Formic acid

CH3(CH2)10COOH

Acetic acid

Lauric acid

COOH

Benzoic acid

CH2COOH

Penylic acetic acid

Carboxylic Acid

Carboxylic acid that are derivated from open-chain alkanes are systematically named by replacing the terminal –e of the corresponding alkane with –oic acid.

The carboxylic carbon atom is always numbered C1 in the system.

NomenclatureNomenclature

Propanoic acid 4-Methylpentanoic acid 3-Ethyl-6-methyloctanedioic acid

IUPACname

Carboxylic Acid

To indicate the position of attachment, the Greek letters, α, β, γ, δ, etc are used.

NomenclatureNomenclature

COMMONname

The α-carbon is the one bearing the carboxyl group.

C-C-C-C-COOHδ α βγ

CH3CH2CH-COOHα βγ

CH3

α- Methylbutyric acid

CH3CH2CH-CHCOOHα βγ

CH3

α,β -Dimethylvaleric acid

CH3

Carboxylic Acid Physical PropertiesPhysical

Properties

Gugus –C=O pada asam karboksilat mempunyai ikatan π, sehingga dapat terjadi resonansi.

Hal yang sama tidak terjadi pada gugus –OH dari alkohol.

C O C Oσ+ σ- Atom O pada karboksilat lebih

bermuatan negatif daripada R-OH

Atom H pada karboksilat lebih bersifat sebagai proton daripada R-OH

Kesimpulan

Ikatan hidrogen pada karboksilat lebih kuat dari ikatan hidrogen pada alkohol.

Carboxylic Acid Physical PropertiesPhysical

Properties

C

O

OCH3

H

CO

O

H3CH

2 Hydrogen bond

Acetic acid DIMER

O

H

R HO

R1 Hydrogen bond

Still MONOMER

The Fact Boiling point of asetic acid = 118 Co

Boiling point of n-Propylalcahol = 97 Co

Carboxylic Acid DissociationDissociation

Like other Bronsted-Lowry acids, carboxylic acid dissociate slightly in dilute aqueous solution to give H3O+ and carboxylic anion, RCOO-

COH

O

RC

O-

O

R+ H2O +

H3O+

As with all acids, we can define an acidity constant, Ka:

Ka = [RCOO-][H3O+]

[RCOOH]and pKa = -log Ka

pKa = -7 pKa = 4,72 pKa = 16

acidity

Carboxylic Acid ResonanceEfect

ResonanceEfect

CH3CH2OH + H2O + H3O+CH3CH2O-

Unstabilized

Ethanol

CO

O

H3CH

+ H2O CO-

O

H3C CO

O-

H3C + H3O+

Resonance stabilized carboxylic ion

Carboxylic Acid SubstituentEfect

SubstituentEfect

STRUCTURE Ka pKaHCl 107 -7

F3CCOOH 0,59 0,23

Cl3CCOOH 0,23 0,64

HCOOH 1,77 x 10-4 3,75

CH3COOH 1,8 x 10-5 4,72

acidity

Carboxylic Acid PreparationPreparation

1. Oxidation of primary alcohol. R-CH2OH KMnO4 R-COOH

CH3CH2CHCH2OH

CH3

KMnO4

2-Methyl-1-butanol

CH3CH2CHCOOH

CH3

2-Methylbutanoic acid

CH3CHCH2OH

CH3

Isobutyl alcohol

KMnO4 CH3CHCOOH

CH3

Isobutylic acid

R-C N

Carboxylic Acid PreparationPreparation

2. Hydrolysis of Nitriles. R-COOH

or

Ar-C N

+ H2OAcid or base

or

Ar-COOH

+ NH3

CH2CN

Phenylacetonitrile

70% H2SO4

CH2COOH

Phenylacetic acid

3. Carbonation of Grignard Reagents.

4. Oxydation of Alkylbenzenes.

5. Malonic Ester Syntesis.

Derivatives of

Carboxylic Acid

CR

O

OH

CR

O

ClAcid chloride

CR

O

OC

R

O

C

R

Anhydride

O

NH2

Amide

CR

O

OR’Ester

Morereactive

Lessreactive

Derivatives of

Carboxylic AcidNomenclatur

eNomenclatur

e

COH

OH3C C

OH

O

C

Cl

O

Acetic acid Benzoic acid

ArR

Change: -ic acid to –yl chloride

CCl

OH3C

Acetyl chloride Benzoyl chloride

Change: acid to anhydride

CO

OH3C

CO

H3C

Acetic anhydride

C

O

O

C

O

Benzoic anhydride

Acid chloride

Anhydride

Derivatives of

Carboxylic AcidNomenclatur

eNomenclatur

e

COH

OH3C C

OH

O

Acetic acid Benzoic acid

ArR

Change: -ic acid to –amide

Change: acid to -ate

CNH2

OH3C

Acetamide

C

NH2

O

Benzamide

C

OC2H5

O

COC2H5

OH3C

Ethylacetate Ethylbenzoate

Amide

Ester

Derivatives of

Carboxylic Acid1.Acid

Chloride[an Acyl)

1.Acid Chloride[an Acyl)

Carboxylic Acids are converted into acid chlorides [an acyl group] by teratment with thyonyl chloride (SOCl2), phosphorus trichloride

(PCl3), or oxalyl chloride (ClCOCOCl).

CR

O

OH

+ SOCl2 CR

O

Cl

+ SO2+ HCl

Derivatives of

Carboxylic Acid

Conversion to :

OHC

R

O

ORC

R

O

NH2

CR

O

HC

R

O

HCH

R

OH

H2O

ROH NH3

[H]

[H]

EsterAcid Amide Aldehyde

Alcohol

ClC

R

O

RC

R

O

R’’MgX

Ketone

t-alcohol

OR

CR

OH

R

R’’MgX

Derivatives of

Carboxylic Acid

With H2O can converted back into carboxylic acid. C

OH

OH3C

Acetic acid

Acetyl chloride

With alcohol can…………………………..

Benzoyl chloride

C Cl

O

H3C + HClHOH

C ClO HOCH3C OCH3O

Methylbenzoate

Ester

+ HCl

Amide formation with amonia. C Cl

O

H3CAcetyl chloride

+ 2NH3 C NH2

O

H3C + NH4ClAcetamide

Derivatives of

Carboxylic Acid2.Acid Anhydrides2.Acid Anhydrides

Preparation :

CCl

O

CH3

CH

O

O-Na+

+C

O

O

CH3

CH

O

Sodium formate Acetyl chloride Acetic formic anhydride

Derivatives of

Carboxylic Acid

Conversion to :C

O

O

RC

R

O

OHC

R

O

ORC

R

O

NH2

CR

O

HC

R

O

HCH

R

OH

H2O

ROH NH3

[H]

[H]

EsterAcid Amide Aldehyde

Alcohol

Derivatives of

Carboxylic Acid

In drugs industry :

NH2

HO

p-Hydroxyaniline

+

O

H3CC O CCH3

ONaOH

N

HO

H

CO

CH3

Acetaminophen

+ O-H3CC

O

C

O

OH

OH

Salicylic acid

+

O

H3CC O CCH3

ONaOH

C

O

OH

O

CO CH3

Aspirin

+ O-H3CC

O

Derivatives of

Carboxylic Acid

Ester is hydroxy group ini acid change into some alkyl or aryl:

3. Ester3. Ester

The ester linkage is also present in animal fats and many biologically important molecules.

CH3CH2CH2C-OCH3

O

Methylbutanoate[from pineaples]

CH3CO-CH2CH2CHCH3

O CH3

Isopentyl acetate[from bananas] A fat

H2C O

HC O

H2C O

C

C

C

O

O

O

R

R

R

Derivatives of

Carboxylic Acid

Conversion to :

OHC

R

O

NH2

CR

O

HC

R

O

HCH

R

OH

H2O

R’’MgX NH3

[H]

[H]

t-alcoholAcid Amide Aldehyde

Alcohol

ORC

R

O

OR

CR

OH

R

+ H-OR

Derivatives of

Carboxylic Acid

Esters are usually prepared by the reaction of alcohols or phenols with acids or acid derivatives.

C OH

O

R C OR

O

R + H-OH

Carboxylic acid alcohol ESTER

CH2OH + HOOCCH3 CH2OOCCH3 + H-OH

Benzyl alcohol Acetic acid Benzyl acetat

ESTERIFICATION

Derivatives of

Carboxylic AcidSAPONIFICATION

ORC

R

OH2O

NaOH

OHC

R

O+ ROH

O-Na+C

R

O

An acid

A soap

Amine

Amine is derivates of ammonia, when one or more of hydrogen change into alkyl (R) or aryl (Ar).

NH H

H

NR H

H

NR R

H

NR R

R

Ammonia Primary

1o

Secondary

2o

Tertiary

3o

Amine

N

N

CH3

N

N

N

H3C

O

O CH3

CH3

Vitamin B2

N

N

N

N

H

OH3C

H3C

O

H2C CH

CH

CH

CH2OH

OH OH OH

N

NH2C N+

H

H3C

CH2CH2OH

H3C

Nicotine Caffeine

Vitamin B1

Amine Nomenclature

Aliphatic amine are named by naming the alkyl group or groups attached to nitrogen, and following these by the word –amine.

H3C C

CH3

CH3

NH2

H3CH2C N

H

CH3

tert-Butylamine Etrhylmetylamine

Amine Nomenclature

Aromatic amine those in which nitrogen is attached directly to an aromatic ring, are generally named as derivatives of the simple aromatic amine, -aniline.

NH2

aniline

NH2

Br

Br

Br

2,4,6-Tribromoaniline

NH3C C2H5

N-Ethyl-N-methylaniline

NH3C CH3

NO

p-Nitroso-N, N-dimethylaniline

NH2

CH3

p-Touidine

Amine Physical Properties

Amine are highly polar and therefore have higher boiling point than alkanes of equivalent molecular weight have, but lower boiling point than alcohol or carboxylic acids.

N

RR

HN

RR

H

N

RR

HN

RR

H

N

RR

H

CP’s BP (oC) Mr

CH3CH3 -88,6 30

CH3NH2 -6,3 31

CH3OH +65,0 32

Amine Reaction

CH3COOHCl2

CH2COOH

Cl

NH3

CH2COOH

NH2Acetic acid

Chloroacetic acidGLYSINE

[an amino acid]

CR

O

ClAcid chloride

CR

O

OC

R

O

C

R

Anhydride

O

NH2

Amide

CR

O

OR’Ester

HOCCH2CHCH2CH2CHCH2COH

OCH3

54321 6 7 8

CH2CH3O

HCl

CH3CH2OH

R-C N