1c stdnt chapter 4 organic chemistry - hydroxyl

7/28/2019 1c Stdnt Chapter 4 ORGANIC CHEMISTRY - Hydroxyl

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CHAPTER 4: ORGANIC CHEMISTRY

ALCOHOLS

HYDROXY

COMPOUNDS

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v

q

OH

qOH orO

q

OH

OH

2


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H

C

H

OHH3C

CH3

C

H

OHH3C

CH3

C

CH3

OHH3C

3


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4


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Naming Alcohols

CH CH CH CH CHCH OH

Give the IUPAC name of thealcohol:

CH2CH2CH3C

C

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CH3OH CH3CH2OH

CH3CH2CHCH3

OHC

CH3

CH3H3CCH3CHCH2OH

CH3

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H2C CH2

OHOH

H2CHC CH2

OHOHOH

H3CHC CH2

OHOH

H3CH2C

HC

H2C CH2

OHOH

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H2C CH

H2C OH H C C

H2C

H2C

H2C OH

2-propen-1-ol4-pentynol

H3C CH

CH

2C

2C OH HOH2C

H

H

CH2CH2CH3

c c

c c

trans-2-hexen-1-ol

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OH OH

NO2

OH

CH3

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Reactions of Alcohols

CH3OH + HBr CH3Br + H2OH+

**Substitution reactions may be used toconvert an alcohol to a haloalkane

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q

(CH3)3COH + HCl (CH3)3CCl + H2Oroom temperature

C2H5OH + HCl(g) C2H5Cl + H2OZnCl2

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reflux

2 5 3 2 5 3 3 3

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2P + 3Br2 2PBr3

3C2H5OH + PBr3 3C2H5Br + H3PO3

6C2H5OH + 2P + 3Br2 6C2H5Br + 2H3PO3

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2 3

3C2H5OH + PI3 3C2H5I + H3PO3

6C2H5OH + 2P + 3I2 6C2H5Br + 2H3PO3

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C2H5OH + PCl5 C2H5Cl (POCl3) + HCl

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C3H7OH + SOCl2 C3H7Cl + SO2 + HClreflux

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R C C H

H H

H OH

R C C H

H H

+ H2Oexcess conc. H2SO4, 170

oC

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Sayt effs rule.

**Dehydration can be used to convert alcohols toalkenes

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H C CHCH2CH3

H

H OH

H2C CHCH2CH3 + H2O

H3CHC C CH3

H

H

H3CHC CHCH3 + H2O

OH (2 alkyl groupsattached to the double bond)

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Saytzeffs rule: For elimination reaction thatproduces more than one alkenes, the alkene withmore than one alkyl substituents in the doublebond is the predominant product.

21

OH 1-pentene (minor product)

2-pentanol 2-pentene (major product)


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H H

+ H2OR C C H

H OH

H2C CH2

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OH 85 % H3PO4, 165-170oC

+ 2

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CH3CH2OH CH2 CH2 + H2O2 3

heat

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The ease of dehydration follows

the order:

OH

R

R OH

R

H OH

H

R

>>

R R H

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Cannot be oxidi ed

KMnO4K2Cr2O7

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Finalproduct

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CH3(CH2)5CH2OH + [O] CH3(CH2)5CHO + H2OPCC

CH2Cl2, 25oC

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OH

H2CrO 4

O

Cyclopentanol

(secondary alcohol)

cyclopentanone

O HH 2C rO 4

O

H

H 2C rO 4

O H

O

Butanol (primary alcohol)butanal

butanoic acid29


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q

sodiumalkoxides) hydrogen gas

CH3OH + Na CH3ONa + H2CH3OH + K CH3OK + H2

potassium methoxide

q

q

30


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31


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32


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Lucas Reagent Test

OH ClZnCl2/ HCl

2-methyl-2-butanol 2-chloro-2-methylbutane

(30 alcohol) (Cloudiness appears immediately)

*Cloudiness isdue to theformation ofalkyl halide

ZnCl2/ HCl

OH Cl2-pentanol 2-chloropentane(20 alcohol) (cloudiness appears in a few minutes)

OH No reactionpropanol (10 alcohol)

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Only 10 and 20 alcohols are oxidised by hot acidifiedKMnO4 or hot acidified K2Cr2O7 solution.

10 and 20 alcohols decolourise the purple KMnO4solution,

whereas the colour of the K Cr O solution chan esfrom orange to green.

No reaction for 30 alcohols.

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q

H3C

H

q I2/ NaOH))

OH

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H3C C R

H

OH

+ 4I2 + 6NaOH CHI3 + RCOONa + 5NaI + 5H2O

CH3CH2OH I2/ NaOH CHI3Triiodomethane (iodoform)yellow precipitate

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H H

H3C C H

OH

H C H

OH

H3C C CH3

H

OH

CH3CH2CH2OH

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Summary

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1c stdnt chapter 4 organic chemistry - hydroxyl

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