Oxidation of alcohols

[O] = oxidizing agent dichromate Cr2O72-

permanganate MnO4-

oxidation =

aldehyde1o alcohol carboxylic acid

1. binding O2. removing H

loss of e- density from C

1+

2-

2- 1+

3+2- 1+1+

1+

1- 1+2-

Cr3+

Alcohols oxidation of alcohols:

[O] = Cr2O72- or MnO4

2-

1o alcohols[O]

aldehyde carboxylic acid[O]

Cr2O72-+ + Cr3+

[O]

methanol

formaldehyde

[O]

formic acid

methanal methanoic acid

Alcoholsoxidation of alcohols:

[O] = Cr2O72- or MnO4

2-

2o alcohols[O]

ketone no reaction[O]

[O]

Alcoholsoxidation of alcohols:

[O] = Cr2O72- or MnO4

2-

3o alcohols[O]

no reaction

H2SO4

Condensation

two molecules combine to formlarger molecule + water

alcohol alcohol ether H2O+ +

CH3 – OH + HO – CH3 CH3 – O – CH3 + H2O

Reaction

Alcohols

Ethers

R

water alcohol ether

-

H-bond acceptor O-

no H-bond donor dipole-dipole interactions

low b.p.soluble in polar solvents

Ethers

Common nomenclature : name both R groups + ether

1 2 3 1 propylmethyl

ethermethyl propyl

methyl

methyl

dimethyl ether

propyl people ether

O “ether” bunny..

EthersReactions

Formation:H2SO4

condensation reaction

Peroxide formation:

peroxide

Aldehydes and Ketones

C=O carbonyl group

aldehyde ketone

C and O are sp2 hybridized

120o

Aldehydes and KetonesNomenclature

1. Longest chain with C=O is parent

2. Suffix is “-al” or “-one”

3. C1 is always C=O in aldehydes In ketones, C=O is given lowest number

4. C=O has precedence over -OH (called “hydroxy”)

1234 albutan2-bromo-3-methyl

one1

2345

pentan3-

cyclobutanone12

3

2-methyl3-hydroxy-

trans-

Physical properties

-+

polar higher b.p. than alkanes

H-bond acceptor soluble in polar solvents

no H-bond donor lower b.p. than alcohols

O..

CH

H .. O..

CH

H ..:+ -

ReactionsReduction

[R] = reducing agent LiAlH4

NaBH4

H2/Pt[R]

[R]

al

one

CH3-CH3-

1234

butan

CH2- CH2- CHO CH2- CH2- CH2-OH

12

3 4

butan2-