Oxidation of alcohols 1o alcohol aldehyde carboxylic acid 1+ 2- 2- 2- 1+ 1- 3+ 1+ 1+ 1+ 1+ 2- 1o alcohol aldehyde carboxylic acid [O] = oxidizing agent dichromate Cr2O72- Cr3+ permanganate MnO4- oxidation = loss of e- density from C 1. binding O 2. removing H
Alcohols oxidation of alcohols: [O] = Cr2O72- or MnO42- [O] [O] 1o alcohols aldehyde carboxylic acid [O] [O] + Cr3+ + Cr2O72- methanol methanal methanoic acid formaldehyde formic acid
Alcohols oxidation of alcohols: [O] = Cr2O72- or MnO42- [O] [O] 2o alcohols ketone no reaction [O]
Alcohols oxidation of alcohols: [O] = Cr2O72- or MnO42- [O] 3o alcohols no reaction
Alcohols Condensation Reaction CH3 – OH + HO – CH3 CH3 – O – CH3 + H2O H2SO4 CH3 – OH + HO – CH3 CH3 – O – CH3 + H2O two molecules combine to form larger molecule + water ether H2O alcohol + alcohol +
Ethers O- - R water alcohol ether H-bond acceptor no H-bond donor dipole-dipole interactions low b.p. soluble in polar solvents
Ethers “ether” bunny Common nomenclature : name both R groups + ether propyl 2 1 3 1 methyl propyl ether methyl methyl dimethyl ether O .. methyl “ether” bunny propyl people ether
Ethers Reactions Formation: Peroxide formation: condensation reaction H2SO4 condensation reaction Peroxide formation: peroxide
Aldehydes and Ketones C=O 120o aldehyde ketone carbonyl group C and O are sp2 hybridized
Aldehydes and Ketones Nomenclature 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”)
2-bromo-3-methyl butan al 3- pentan one trans- 3-hydroxy- 2-methyl 4 2 1 3- pentan one 1 4 2 5 3 trans- 1 2 3-hydroxy- 2-methyl cyclobutanone 3
Physical properties O .. C H O .. C H : - polar + + - polar higher b.p. than alkanes H-bond acceptor soluble in polar solvents no H-bond donor lower b.p. than alcohols
Reactions Reduction [R] = reducing agent LiAlH4 NaBH4 H2/Pt butan al 3 1 2 CH3- CH2- CH2- CHO CH3- CH2- CH2- CH2- OH butan al [R] 1 3 4 2 2- butan one