alcohols

Functional Group

Alcohol

Organic Name :

Group 1 :Abdurrohman Dzaky Al Hafidz

M. Andika AryanaReky Hermawan

Saptio AjiSuhartini Lestari Putri

Definition

Classification

Properties

PhysicalProperties

ChemicalProperties

Alcohols

Important Individual Alcohol

Nomenclature

Preparation

Definition

• Alcohol are compounds in wich a hydroxyl group (-OH) is attached to a saturated carbon

• The general formula of alcohol is ROH (R= alkyl, substitution alkyl, or syclic hidrokarbon)

Example: CH3-OH (metanol)

CH3CH-OH (etanol)

Alcohols

Nomenclature of Alcohols

• IUPAC SystemStep 1 : Name the longest chain to which the hydroxyl group is attached. (alkane –e + ol = Alkanol)Step 2 : Number the longest chain to give the lowest number to the carbon attached to the hydroxyl groupStep 3: Indicate the position of the hydroxyl group by the number of the carbon atom to which is attachedStep 4: Indicate the position of other substitutients or multiple bonds by number

Alcohols

Nomenclature of Alcohols

• IUPAC SystemExample:

3 2 1

CH3CH2CH2OH 1-propanol 1 2 3

CH3CH2CH2 2-propanol

OH

Alcohols

Classification of Alcohols

Monohydric alcohols are classified as primary (1o), secondary (2o), or tertiary (3o) :

• In primary (1o) alcohols the –OH is attached to a C atom which is attached to one other

• In secondary (2o) alcohols the –OH is attached to a C atom which is attached to two other

• In tertiary (3o) alcohols the –OH is attached to a C atom which is attached to three other

Alcohols

Classification of Alcohols

Example:primary (1o) : R-CH2-OH

CH3-CH2-CH2-OH 1-propanol (n-propyl alcohol)

secondary (2o):

R-CH-OH R’

CH3-CH-OH 2-propanol (isopropyl alcohol)

CH3

Alcohols

Classification of Alcohols

Example:tertiary (3o) :

CH3

CH3-CH-OH 2-methyl-2-propanol (t-buthyl alcohol)

CH3

R’’R-CH-OH R’

Alcohols

Physical Properties of Alcohols

• Boiling PointsAlcohol have hinger boiling points than alkanes of similar molecular weight. Alcohol boiling points increase as carbon-chain length increases.Example:CH3-OH methyl alcohol BM= 32 oC= 65

CH3-CH2-OH ethyl alcohol BM= 46 oC= 78CH3-CH2-CH2-OH n-propyl alcohol BM= 60 oC= 97

Alcohols

Physical Properties of Alcohols

• SolubilityThe polar part of the alcohol molecule increases solubility in water, but the non polar part decrease solubility.Size of the non polar alkyl group is large the solubility of alcohol in water decrease dramatically

Alcohols

1. Reaction with active metalsAlkoxides are formed by Na, Mg, Al etc

H3C-CH2-OH H3C-CH2-ONa Sodium ethoxide

Na

Chemical Properties of Alcohols

Alcohols

2. Ester Formation OH3C-CH2-OH + H3C-CH2-C-OH

ethanol propanoic acid

OH3C-CH2-C-O-CH2-CH3 + H2O

diethyl ester

Alcohols

Alcohols

3. Dehydration (Reaction with sulphuric acid)a. Alkene Formation

Conc. H2SO4 OH

H3C-CH2-CH-CH3

H3C-CH2-CH=CH2

1-butene

Minor Product

H3C-CH=CH-CH3

2-butene

Major Product

+

Alcohols

3. Dehydration (Reaction with sulphuric acid)b. Ether Formation

Conc. H2SO4 2 H3C-CH2-OHethanol

H3C-CH2-O-CH2-CH3

diethyl etherH2O+

140o

Alcohols

3. Dehydration (Reaction with sulphuric acid)c. Alkyl hydrogen sulphates formation

roomH3C-CH2-OHethanol

H3C-CH2-O-SO2OH Ethyl hydrogen sulphate

H2O

+temperature

HO-SO2OH

+

Alcohols

4. Alkyl halides formation (R-X)a. Reaction with thionyl chloride (SOCl2)

H3C-CH2-OHethanol

H3C-CH2-Cl Ethyl chloride

SO2+ SOCl2+ + HCl

Alcohols

4. Alkyl halides formation (R-X)b. Reaction with phosphorus halides (PX3 or PX5)

H3C-CH2-OHethanol

H3C-CH2-Cl Ethyl chloride

POCl3+ PCl5+ + HCl

3 H3C-CH2-OHethanol

+ PCl3

H3C-CH2-Cl Ethyl chloride

+ H3PO3

Alcohols

5. Reaction with hydrogen halides (HX)HCl react with alcohols only in the presence of catalyst (anhydrous ZnCl2). No catalyst is required in the case of HBr or HI

H3C-CH2-OHethanol

+ HBr + H2OH3C-CH2-Br Ethyl bromide

Alcohols

6. Reaction withnitric acid (HNO3)alkyl nitrates are formedH3C-CH2-OH + HBr H3C-CH2-O-NO2 + H2O

ethanol ethylnitrate

7. Oxydation Different types of alcohols give different products on

oxidation. Most widely used oxidizing agents are KMnO4 + H2SO4 and Na2Cr2O7 + H2SO4

Alcohols

a) Primary alcohols are oxidized to aldehydes, which are, in turn, easily axidized to carboxilic acids. The reaction can be stoped at the aldehyde stage, by removing them from the oxidizing medium as they are farmed (e.g. Destilation)

OO

H3C-CH2-OH + H3C-C-H H3C-C-OH

Ethylalcohol acetaldehyde aceticacid

Alcohols

b.) secondary alcohol are oxidazed to ketones O O

H3C-CH-CH3 + H3C-C-CH3 + H2OIsoprophyl alcohol acetone

c.) Tertiary alcohol don’t undergo oxidation under normal condition. OH

H3C-C-CH3 + NO REACTION (NR)

CH3

Tert-buthyl alcohol

Alcohols

8. Reaction with hot copper ( catalytic dehydrogenation)

Different types of alcohols give different products when their vapours are passed over copper gauze at 3000C

a) Primary alcohols give aldehydes + hydrogen O

H3C-CH2-OH H3C-C-H + H2

Ethylalcohol Acetaldehyde

Alcohols

b. ) Secondary alcohols give ketone + hydrogen OH O

H3C-C-CH3 H3C-C-CH3 + H2Isoprophyl alcohol Acetone

c. ) Tertiary alcohols give alkenes + water OH CH2

H3C-C-CH3 H3C-C + H2O

CH3 CH3Tert-butyl alcohol 2-methyl propene

Preparation of Alcohols

1. Hydrolysis of Alkyl halides with aqueous NaOH

Keduanya akan berikatan menjadi NaBrH2C CH2 OHH3C

propanol

Bagian OHnya akan pindah

H2C CH2 BrH3C

1-bromopropane

NaOH 𝐻2𝑂→

Alcohols

CH2 CH

OSO3H

CH3

sec-butyl hydrogen sulfate

H3C

H2C CH CH2H3C

butene

HOSO3H

Sesuai hukum Markovnikov maka bagian positifnya akan menuju ke bagian C yang Hnya paling banyak

H2C CH CH2H3C

butene

HOSO3H

2. Hydration of AlkenesAlkenes react with conc. H2SO4 to form alkyl hydrogen sulphates which on hydrolysis yield alcohols

Alcohols

CH2 CH

OSO3H

CH3

sec-butyl hydrogen sulfate

H3C

H

O H

CH2 CH

OH

CH3

butanol

H3C H2SO4

Keduanya akan berikatan menjadi H2SO4

Bagian OHnya pindah karena bagian OSO3 yang bermuatan negatif sudah berikatan dengan H

CH2 CH

OSO3H

CH3

sec-butyl hydrogen sulfate

H3C

H

O H

Alcohols

C

OMgX

R

addition

3. Addition of Reagents to aldehydes and ketones

C

O

aldehyde

R MgX

Grignard

Ikatan double bond putus. Bagian R akan pindah ke C. Bagian MgX akan pindah ke O

𝐻2𝑂→H+

OMgX akan menjadi OH saat bereaksiC

OH

R

alcohol

MgX(OH)

Alcohols

H C H

O

R MgXH C H

OMgX

R

𝐻2𝑂→H+

• Primary AlcoholsObtained by treating Grignard reagents with formaldehyde

H C H

OH

R

MgX(OH)

Ikatan double bond putus. Bagian R akan pindah ke C. Bagian MgX akan pindah ke O

OMgX akan menjadi OH saat bereaksi

Alcohols

𝐻2𝑂→H+

• Secondary AlcoholsObtained by treating Grignard reagents with other aldehyde

MgX(OH)

Ikatan double bond putus. Bagian R akan pindah ke C. Bagian MgX akan pindah ke O

OMgX akan menjadi OH saat bereaksi

R MgXCH3 C H

O

H3C C H

OMgX

R

H3C C H

OH

R

Alcohols

𝐻2𝑂→H+

• Tertiary AlcoholsObtained by treating Grignard reagents with ketones

MgX(OH)

Ikatan double bond putus. Bagian R akan pindah ke C. Bagian MgX akan pindah ke O

OMgX akan menjadi OH saat bereaksi

R MgXCH3 C CH3

O

H3C C CH3

OMgX

R

H3C C CH3

OH

R

Alcohols

4. Reduction of aldehydes and ketones with H2/Ni or lithium aluminium hydride (LiAlH4)

Aldehydes give primary alcoholsKetones give secondary alcohols

H3C CH2 OH

ethyl alcohol (1o)

Alcohols

H3C C H

O

acetaldehyde

𝑁 𝑖→

Ikatan rangkap putus O pindah ke H menjadi OHH akan berikatan dengan C

H3C CH

OH

CH3

isopropyl alcohol (2o)

Alcohols

H3C C CH3

O

acetone

𝐿𝑖𝐴𝑙𝐻 4→

Setelah bereaksi ikatan double bond hilang dan O menjadi OH

5. Reduction of acids with lithium aluminium hydride (LiAlH4)

H3C CH2 CH2 C

O

OH

butyric acid

H3C CH2 CH2 CH2 OH

butan-1-ol

𝐿𝑖𝐴𝑙𝐻 4→

Setelah bereaksi ikatan double bond dan O hilang

Alcohols

6. Acid-hydrolysis of esters

C3H7OH

propan-1-ol

H3C C

O

OH

acetic acid

H3C C

O

OC3H7

propyl acetate

H

O H

Keduanya akan bereaksi menjadi C3H7OHOH akan pindah sehingga akan membentuk asam asetat

Alcohols

Important Individual Alcohols

• Methanol (methyl alcohol, wood alcohol). In industry, it is used as the raw material for making formaldehyde, as a solvent, and as a denaturant.

• Ethanol (ethyl alcohol, grain alcohol). In industry ethanol is used as a solvent and to prepare perfumes, lotions, and rubbing compound.

• 2-propanol (isopropyl alcohol) otu used as a disinfectant

Alcohols

Important Individual Alcohols

• 1,2-ethanediol (ethylene glycol) and 1,2- propanediol (propylenglycol) are components in permanent type antifreezes.

• 1,2,3-propanetriol (glycerol, glycerin) it used as afood additive to help keep food moist

• Sugars. All carbohydrates consist of polyhydroxy compounds

Alcohols

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