1. Alcohols R-O-H Classification CH3, 1o, 2o, 3o Nomenclature:
Common names: “alkyl alcohol”
IUPAC: parent = longest continuous carbon chain containing the –OH group.
alkane drop -e, add –ol
prefix locant for –OH (lower number for OH)

2. CH CH3
CH3CHCH2CHCH3 CH3CCH3
OH OH
4-methyl-2-pentanol tert-butyl alcohol
2-methyl-2-propanol
2o o
CH3
HO-CHCH2CH3 CH3CH2CH2-OH
sec-butyl alcohol n-propyl alcohol
2-butanol propanol
2o o

3. Physical properties of alcohols:
polar + hydrogen bonding
relatively higher mp/bp
water insoluble!
(except for alcohols of three carbons or less)
CH3CH2CH2CH2CH2CH2CH2CH2CH2CH2-OH
hydrophobic hydrophilic

4. Oldest known organic synthesis:
“fermentation”
Sugar yeast  ethyl alcohol CO2
Grape juice => “wine”
Barley => “beer”
Honey => “mead”
Rice => “sake”
~5-11% ethanol

5. Alcohols, synthesis: 1. 2. 3.
4. Hydrolysis of alkyl halides (CH3 or 1o) 5. 6. 7. 8.

6.  NR some 1o/2o R-H R-X R-OH Acids Bases Active metals Oxidation
Reduction
Halogens

7. Alcohols, reactions:
R-|-OH
With HX
With PX3
(later)
RO-|-H
As acids
Ester formation
Oxidation

8. 1. Reaction of alcohols with HX: (#1 synthesis of RX)
R-OH HX  R-X H2O
a) HX: HI > HBr > HCl
b) ROH: 3o > 2o > CH3 > 1o
c) May be acid catalyzed
d) Rearrangements are possible except with most 1o alcohols.

9. CH3CH2CH2CH2-OH + NaBr, H2SO4, heat  CH3CH2CH2CH2-Br
n-butyl alcohol n-butyl bromide
1-butanol bromobutane
CH CH3
CH3C-OH HCl  CH3C-Cl (room temperature)
tert-butyl alcohol tert-butyl chloride
2-methyl-2-propanol 2-chloro-2-methylpropane
CH3CH2-OH HI, H+, heat  CH3CH2-I
ethyl alcohol ethyl iodide
ethanol iodoethane

10. Mechanism?
CH3-OH and most 1o alcohols react with HX via SN2 mechanism
3o and 2o react with HX via SN1 mechanism
Both mechanisms include an additional, first step, protonation of the alcohol oxygen:
R-OH H+  R-OH “oxonium ion”

11. Whenever an oxygen containing compound is placed into an acidic solution, the oxygen will be protonated, forming an oxonium ion.

12. Mechanism for reaction of an alcohol with HX:
CH3OH or 1o alcohols:

13. Mechanism for reaction of an alcohol with HX:
2o or 3o alcohols:

14. May be catalyzed by acid.
SN2 rate = k [ ROH2+ ] [ X- ]
SN1 rate = k [ ROH2+ ]
Acid protonates the -OH, converting it into a better leaving group (H2O), increasing the concentration of the oxonium ion, and increasing the rate of the reaction.

15. Rearrangements are possible (except with most 1o alcohols):
CH CH3
CH3CHCHCH HBr  CH3CCH2CH3
OH Br
  Br-
CH CH [1,2-H] CH3
CH3CHCHCH3  CH3CHCHCH3  CH3CCH2CH3 OH
2o carbocation o carbocation

17. Most 1o? If large steric requirement…
CH CH3
CH3CCH2-OH HBr  CH3CCH2CH3
CH Br
neopentyl alcohol bromo-2-methylbutane
 
CH CH CH3
CH3CCH2-OH2+  CH3CCH2+  CH3CCH2CH3
CH CH
1o carbocation o carbocation
[1,2-CH3]

18.  With PX3 ROH + PX3  RX PX3 = PCl3, PBr3, P + I2 No rearrangements
ROH: CH3 > 1o > 2o
CH CH3
CH3CCH2-OH PBr3  CH3CCH2-Br
neopentyl alcohol ,2-dimethyl-1-bromopropane 

19. Dehydration
(later)

20. As acids.
With active metals:
ROH Na  RONa ½ H2 
With bases:
ROH NaOH  NR!
CH4 < NH3 < ROH < H2O < HF

21. CH3CH2OH + NaOH  H2O + CH3CH2ONa
WA WB SA SB
CH3CH2OH CH3MgBr  CH MgBr(OCH2CH3)
SA SB WA WB
CH3OH NaNH  NH CH3ONa
SA SB WA WB

22. Ester formation. CH3CH2-OH + CH3CO2H, H+  CH3CO2CH2CH3 + H2O
CH3CH2-OH CH3COCl  CH3CO2CH2CH HCl
CH3-OH CH3SO2Cl  CH3SO3CH HCl
Esters are alkyl “salts” of acids.

27. oxidation states of carbon
CH CH3OH CH2O HCO2H CO2
 reduction -

28. Oxidation
Oxidizing agents: KMnO4, K2Cr2O7, CrO3, NaOCl, etc.
Primary alcohols:
CH3CH2CH2-OH KMnO4, etc.  CH3CH2CO2H
carboxylic acid
Secondary alcohols:
OH O
CH3CH2CHCH K2Cr2O7, etc.  CH3CH2CCH3
ketone
Teriary alcohols:
no reaction.

29. Primary alcohols ONLY can be oxidized to aldehydes:
CH3CH2CH2-OH C5H5NHCrO3Cl  CH3CH2CHO
pyridinium chlorochromate (PCC) aldehyde or
CH3CH2CH2-OH K2Cr2O7, special conditions 

30. Alcohols, synthesis: 1. 2. 3.
4. Hydrolysis of alkyl halides (CH3 or 1o) 5. 6. 7. 8.

31. Alcohols, reactions:
R-|-OH
With HX
With PX3
(later)
RO-|-H
As acids
Ester formation
Oxidation