Download alcohols03

CHAPTER 17
ALCOHOLS & PHENOLS:
Generalizations:
 Alcohols and phenols may be thought of as organic derivatives of water (H-O-H). If one H is
replaced by an alkyl group (R-), the compound is an alcohol (R-OH) and if the H of water is
replaced by an aromatic group (Ar-), the compound is a phenol (Ar-OH). Although alcohols
and phenols have the same functional group (a hydroxyl group), their physical properties are
very different.
Alcohols:
 Alcohols are classified as 1, 2, or 3 depending upon the number of carbon atoms bonded to
the -carbon, i.e., the carbon bearing the functional group (-OH in this case).
R
H
R
C OH
H
1º  carbon
R
C OH
H
2º  carbon
R
R
C OH
R
3º  carbon
Sec. 17.1 Naming Alcohols:
 Common names are derived by naming the alkyl group attached to the -OH group and then,
after leaving a space, name the -OH group as 'alcohol'. They are literally ‘alkyl alcohols’.
 IUPAC names are derived by replacing the terminal '-e' in the alkane with '-ol' giving an
‘alkanol’, written as a single word.
1. As with alkenes and alkynes, choose the longest carbon chain containing the
- carbon atom, i.e., the carbon that bears the hydroxyl (-OH) group.
2. Number the chain to give -OH the lowest number.
3. List the substituents on the chain alphabetically.
CH3OH
CH3CH2OH
CH3CH2CH2OH
c
methyl alcohol (carbinol)
ethyl alcohol
n-propyl alcohol
I
methanol
ethanol
1-propanol
OH
CH3CHCH3
OH
CH3CH2CH2CH2OH
CH3CH2CHCH3
c
isopropyl alcohol
n-butyl alcohol
sec-butyl alcohol
I
2-propanol
1-butanol
2-butanol
ALCOHOLS & PHENOLS
1
CH 3
CH 3 C OH
OH
CH 3CH 2CH 2CH 2CH 2OH
CH 3CHCH 2CH 2CH 3
CH 3
c
t-butyl alcohol
n-pentyl alcohol
n-amyl alcohol
--------------
I
2-methyl-2-propanol
1-pentanol
2-pentanol
CH 3
OH
CH 3
CH 3CHCH 2CH 2OH
CH 3CH 2CHCH 2CH 3
CH 3CCH 2CH 3
OH
c
isopentyl alcohol
------------------
t-pentyl alcohol
isoamyl alcohol
I
3-methyl-1-butanol
t-amyl alcohol
3-pentanol
2-methyl-2-butanol
OH
CH 2OH
OH
c
benzyl alcohol
cyclopentyl alcohol
I
phenylmethanol
cyclopentanol
Br
-------------trans-2-bromocyclohexanol
Note that in cyclic alcohols, the -OH group is automatically on carbon # 1.
CH 2=CH-CH 2OH
OH OH
OH
CH 2-CH 2
CH 2-CH-CH 2
OH
OH
c
allyl alcohol
ethylene glycol
I
2-propen-1-ol
1,2-ethanediol
OH
CH 2CH 3
CH 3
CH 3
CHCHCH 3
CH 3
OH
neopentyl alcohol
I
2,2-dimethyl-1-propanol
ALCOHOLS & PHENOLS
1,2,3-propanetriol
CH 3CCH 2OH
c -----------2-ethylcyclobutanol
glycerol
glycerin
------------------3-phenyl-2-butanol
2
Nomenclature of Phenols:
Phenols are usually named as derivatives of the parent compound, phenol. Note that phenol is both a
specific compound and a class of compounds. In addition, methyl substituted phenols are called
cresols while benzene diols have names based on their historical uses rather than their structures.
OH
OH
OH
c
carbolic acid
-naphthol
-naphthol
I
phenol
1-naphthol
2-naphthol
H3C
H3C
CH3
OH
OH
c
p-cresol
m-cresol
I
4-methylphenol
3-methylphenol
OH
o-cresol
2-methylphenol
HO
OH
OH
OH
c
catechol
resorcinol
I
1,2-benzenediol
1,3-benzenediol
HO
OH
hydroquinone
1,4-benzenediol
OH
H3C
HO
CH3
CH(CH 3)2
Br
I
biphenyl
2-methyl-4-(1-methylethyl)phenol
4-bromo-2-methylphenol
4-isopropyl-2-methylphenol
Do problems 17.1 & 17.2
ALCOHOLS & PHENOLS
3
Sec. 17.1
Sources and Uses of Simple Alcohols:
1. Methanol (methyl hydrate, methyl alcohol, wood alcohol, carbinol) was formerly produced by
pyrolysis (destructive distillation) of wood. It is commonly used as ‘gas line antifreeze’. Methanol
is toxic by ingestion, causing blindness in small amounts (15 mL) and death in larger amounts.
Methanol is produced commercially by catalytic reduction of CO. The catalyst is ZnO/CrO3.
CO + 2 H2
400 ºC

CH3OH
ZnO / CrO3
2. Ethanol (ethyl alcohol, alcohol, grain alcohol) has been produced for several thousand years by
fermentation of grains and sugars. Currently, most (~95%) of the ethanol produced industrially is
by acid-catalyzed hydration of ethylene.
H
H
C
H
+
H HSO4
H
-
C
H
H2O
H
C
H
H
C+
H
H
O
H
H
H
H
C
C
H
O+
H
H
H
H
H
C
C
H
H
HSO4 -
OH
+
H3O+
3. Phenol occur widely in nature. Phenol itself is a general disinfectant found in coal tar; methyl
salicylate is a flavoring in oil of wintergreen; urushiols are allergens in poison oak and poison ivy.
OH
OH
OH
C
OCH3
O
phenol
methyl salicylate
(methyl 2-hydroxybenzoate)
OH
R
urushiols
(R= C15 alkyl and alkenyl chains)
Boiling Points:
 Alcohols and phenols have similar geometry to HOH. The R-O-H bond angle is approximately
tetrahedral (109) and the ‘O’ atom is sp3 hybridized.
 Because of the presence of the hydroxyl group, alcohols (and phenols) have significantly higher
boiling points than their constitutional (structural) isomers, the ethers. For example, ethyl alcohol
and dimethyl ether are constitutional isomers having the same molecular weight (46). The bp of
ethanol is 78 C and the bp of dimethyl ether is -24C, a difference of 102 C! The hydroxyl
groups of alcohols and phenols form intermolecular hydrogen bonds. The attractive force of
hydrogen bonds must be overcome when molecules in the liquid separate into the gaseous state
during boiling.
 The bp of ethers are similar to those of alkanes of equivalent MW. For example, diethyl ether
(‘Quick Start’) with MW = 44, has a bp of 35 C and n-pentane (MW = 44) is also 35 C.
 Similarly, phenols have higher bp’s than aromatic ethers and aromatic hydrocarbons for the same
reasons as discussed above. Phenol has a mp of 43 C and toluene has a mp of -95 C.
Do problem 17.3
ALCOHOLS & PHENOLS
4
H
Solubility:
The hydroxyl group of alcohols is the first functional group we have encountered that has a
large effect on water-solubility of the organic compound. In general, alkanes, alkenes, alkynes,
arenes and their halogen derivatives (alkyl halides, etc.) are insoluble in water.
The presence of the -OH group makes alcohols with up to 3 carbons miscible (infinitely
soluble) in water. As the carbon chain becomes longer, the solubility decreases; as it becomes
more branched, the solubility increases somewhat.
Hydrocarbon Solubility in Water
Compound
n-pentane
carbon tetrachloride
n-butyl bromide
1,5-hexadiene
H2O Solubility (g/100 mL, 25 C)
0.05
0.08
0.06
0.10
Alcohol and Ether Solubility in Water
Compound
n-butyl alcohol
sec-butyl alcohol
isobutyl alcohol
tert-butyl alcohol
n-pentyl alcohol
n-hexyl alcohol
1-heptanol
phenol
1-octanol
1,4-butanediol
3-chloro-1-butanol
dimethyl ether
diethyl ether
diisopropyl ether
H2O Solubility (g/100 mL, 20 C)
9
12
10
miscible
2.7
0.6
0.2
6.7
0.05
miscible
insoluble
very soluble
7
insoluble
Note that the addition of an extra hydroxyl group in diols (vs. alcohols) increases solubility but
the halogen atom has the opposite effect.
A compound is considered ‘soluble’ if its solubility exceeds 3 parts of compound per 100 parts
of solvent, i.e., 3%.
Ethers of low MW have some solubility in water because the O-atom of an ether carries a
partial negative charge and is therefore a H-bond acceptor.
ALCOHOLS & PHENOLS
5
SEC. 17.3
PROPERTIES OF ALCOHOLS/PHENOLS: ACIDITY & BASICITY
Like water, alcohols and phenols are both weakly basic and weakly acidic, i.e., amphiprotic.

As bases, they are reversibly protonated by strong acids to yield oxonium ions, ROH2+
H
R

..
O
..
+
H
H
+
X
R
O
..
H
+
X-
As acids, they dissociate to a slight extent in dilute aqueous solution by donating a proton to
water, generating H3O+ and an alkoxide ion, RO-, or a phenoxide ion, ArO-.
R
..
O
..
..
H
+
H2O
..
R
.. _
O:
..
+
+
H3O
..
The acidity constants of some alcohols are listed and compared with water ...
Alcohol
(CH3)3COH
pKa
18.00
CH3CH2OH
16.00
HOH
CH3OH
CF3CH2OH
15.74
15.54
(CF3)3COH
p-aminophenol
phenol
p-nitrophenol
2,4,6-trinitrophenol
5.4
12.43
10.5
9.9
7.2
0.60



Simple alcohols, like methanol and ethanol have acidity similar to water.
t-butyl alcohol is less acidic because its alkoxide anion is bulky and not easily solvated by water
2,2,2-trifluoroethanol is more acidic than ethanol because the highly electronegative F-atoms
inductively withdraw electron density from the alkoxide anion thus stabilizing the anion
 nonafluoro-tert-butyl alcohol is quite acidic because of its 9 highly electronegative F-atoms.
Because alcohols are only weakly acidic, they don't react with weak bases such as bicarbonates,
ammonia, or amines and they only react to a very slight extent with metal hydroxides, e.g., NaOH.
Prove this to yourself by calculating (pKeq) for several alcohols and these bases.
Alcohols, like H2O, do react with alkali and alkaline earth metals (Na, Mg, etc.) and with very strong
organic bases such as sodium hydride (NaH), sodium amide (NaNH2), alkyllithium reagents (RLi)
such as methyl lithium (:CH3- Li+) and Grignard reagents (RMgX) such as methyl magnesium
bromide (:CH3- +MgBr). Metal alkoxides themselves are strong bases that are frequently used in
organic chemistry.
Phenols are ca. 106 times more acidic than alcohols. They are soluble in dilute aq. NaOH soln. The
phenoxide anion is resonance stabilized (negative charge is delocalized over the o- and p-positions.
Electron donating groups reduce the acidity of phenols but withdrawing groups increase phenolic

Do problems 17.4 and 17.5.
ALCOHOLS & PHENOLS
6
Sec. 17.4, 17.5 & 17.6
Preparation of Alcohols:
Alcohols can be prepared from many compounds and are likewise used to prepare many
compounds...
O
ROH
O
O
O
RX, R-C-OH, R-C-OR, R-C-R', R-C-H, R-O-R',
C=C
Methods of Preparation of Alcohols:
1. Hydrolysis of Alkyl Halides: OH-, a strong base and a good nucleophile, can displace a halide
from methyl and 1º alkyl halides (a nucleophilic substitution reaction) producing alcohols. The
reaction does not apply to 2º and 3º alkyl halides because strong bases cause them to eliminate HX
(an elimination reaction) forming alkenes.
reflux
CH2CH2CH2Br
+ NaOH (aq)
CH2CH2CH2OH + NaBr
CH3
SN2
CH3
CH3CHCH2I + NaOH (aq)
+
CH2CH2Cl
CH3CHCH2OH + NaI
CH2CH2OH
NaOH (aq)
+
NaCl
Reflux means boiling the system without boiling anything over, i.e., recondensing above the
distillation flask with a condenser.
E2
H
H
H
Br
H
H
C
C
C
C
H
H
H
H
H
+
Na+ OH-
E2
H
2º alkyl halide
H
C
C
C
C
H
H
H
H
NaBr
H
+
H2O
Zaitsev product is major product
2. Hydration of Alkenes:
Acid catalyzed hydration follows Markovnikov’s rule and is subject to rearrangement via
hydride or methide shifts, e.g., 1º C+  2º C+  3º C+.
+
-
H H SO4
H 3C
CH
CH2
H 2O
CH3
+
CH
CH3
CH3
CH
CH3
O+
-
H SO4
H
H
CH3
CH
CH3
OH
Recall that Markovnikov alcohols can be produced by hydration of alkenes without
rearrangement via oxymercuration-demercuration (1. Hg(OAc)2 in THF (aq.), 2. NaBH4)
Also recall that anti Markovnikov alcohols are produced from alkenes by hydroborationoxidation (1. BH3 in THF, 2. H2O2, pH 8)

Do problem 17.6 a) & b)
ALCOHOLS & PHENOLS
7
3. Reduction of Aldehydes and Ketones:
Sodium borohydride (NaBH4) is a safe, effective reducing agent for this reaction.
Aldehydes are reduced to 1 alcohols. Ketones are reduced to 2 alcohols. Carbon-tocarbon double bonds in both these compounds are not reduced.
Lithium aluminum hydride (LiAlH4) can also be used, giving higher yields, but it is
explosive in water and when heated.
O
C H 3C H 2C H 2C
1.
OH
N a B H 4 , e th a n o l
H
2.
H 3O
C H 3C H 2C H 2C
+
H
H
1-butanol (85%)
(a 1º alcohol)
butanal
Mechanism:
.. : O:
: O:
R
C
+
H
H-
R
C
+
O
H
..
: OH
H
..
H
H
R
H
alkoxide
C
H
+
H2O
..
H
The carbonyl carbon is electrophilic (+). Hydride is a strong base (pKb = -21) and is the
most powerful of nucleophiles. As hydride bonds with the carbonyl carbon, the C-to-O 
bond (the weakest bond) breaks (carbon can never have 5 bonds). The electronegative
oxygen atom readily accepts the negative charge. In a second step, dilute aqueous acid is
added. The hydronium ion protonates the alkoxide producing an alcohol and destroys any
excess hydride reagent at the same time.
O
OH
H
C
1.
2.
C
N a B H 4 , e th a n o l
H 3O
+
dicyclohexyl ketone
1,1-dicyclohexylmethanol
(a 2º alcohol)
O
2-cyclohexenone
H
1.
LiAlH4, ether
2.
H3O+
(88%)
OH
2-cyclohexen-1-ol (94%)
Note that hydrides do not reduce (saturate) alkenes since alkenes are also nucleophilic.
ALCOHOLS & PHENOLS
8
4. Reduction of Carboxylic Acids and Esters:
These reactions require a stronger reductant than NaBH4, which reduces esters very slowly
and does not reduce carboxylic acids. LiAlH4 is effective here, reducing both esters and
carboxylic acids to 1 alcohols.
O
C H 3( C H 2) 7C H
C H ( C H 2) 7C
9-octadecenoic acid
(oleic acid)
O
CH3CH2CH
CH
C
H
1. L i Al H 4 , e th e r
C H 3( C H 2) 7C H C H ( C H 2) 7C
OH
+
2.
H 3O
H
9-octadecen-1-ol (87%)
O H + H 2O
1. LiAlH4, ether
OCH3
CH3CH2CH
2.
methyl 2-pentenoate
CH
+
CH2OH
CH3OH
+
H3O
2-penten-1-ol
methanol
Note that 2 H's are added to a carboxylic acid from LiAlH4 and 1 H from H3O+.
Note that a total of 4 H's are added when esters are reduced and two 1º alcohols are formed.
H3O+
H3O+
:O:
R
C
..
_
:O:
..
O
..
:H
+
R'
_
R
..
..O
C
:O :
OR'
R
R'
:H
H
ester
_
_
C
+
H
O:
R
C
R
C
_
..
O
..
H
+
:H
_
:O:
1º alcohol
H2
R
carboxylic acid
C
..
O
.. :
..
H2O
+
H
O:
R
C
1º alcohol
:O:
_
:H
_
_
..
AlH3
R
:O :
..
..O
C
-
AlH3
H
H3O+
R
:H
_
H
H
H
carboxylate
C
H
2 H2O
:O:
R
H
_
..
R'OH
..
: O:
C
H
_
..
: O:
H
R
C
H
H
H
alkoxide
Hydride is a strong base and so will first abstract an acidic hydrogen (proton) from the carboxylic acid.
Hydride is such a strong nucleophile that it can attack even the negatively charged carboxylate anion (the
carbonyl carbon in the carboxylate is only weakly electrophilic). The –- OAlH3 is a very poor leaving
group (very reactive) and only leaves because H- is even more reactive. Note that aldehydes, esters and
carboxylic acids all reduce to 1º alcohols with hydride. Only ketones are reduced to 2º alcohols.

Do problems 17.7 & 17.8.
ALCOHOLS & PHENOLS
9
5. Reduction of Carbonyls with Grignard Reagents:
Grignards, RMgX, reduce carbonyl compounds to alcohols similar to LiAlH4
O
O- +MgX
1. RMgX in ether
C
C
+
2.
OH
H3O
C
R
+
HOMgX
R
Grignard reagents: When Mg metal is added to alkyl halides, aryl halides, or vinylic halides
in a solvent such as ether or tetrahydrofuran (THF), Mg is inserted between the -carbon and
the halide; the carbon becomes strongly electronegative (and nucleophilic).
CH3-Br + Mg 
R-X + Mg  R-MgX
or in general ….
CH3-MgBr
where R = 1º, 2, or 3 alkyl, aryl, or vinylic
where X = Cl, Br, or I
Grignards are useful reducing agents. They react with formaldehyde, CH2=O, to give
1 alcohols. They react with higher aldehydes to give 2 alcohols, and with ketones and esters
to give 3 alcohols.
H
MgBr
+
O
1. Mix
C
2. H3O+
H
H
cyclohexyl
magnesium
bromide
formaldehyde
O
CH3
MgBr
+
CH3CHCH2
H
CH3
OH
CH3CHCH2
C
1. Mix in ether
C H
2. H3O+
H
3-methyl-1-phenyl-1-butanol (73%)
(a 2º alcohol)
OH
O
2. H3O+
ethyl
magnesium
bromide
cyclohexanone
O
CH3CH2CH2CH2
C
1-ethylcyclohexanol (89%)
( a 3º alcohol)
OH
1. 2 CH3MgBr
CH3CH2CH2CH2
OCH2CH3
ethyl pentanoate

CH2CH3
1. Mix in ether
+
CH3CH2MgBr
OH
cyclohexylmethanol (65%)
(a 1º alcohol with a longer C chain)
3-methylbutanal
phenyl
magnesium
bromide
C
2.
2 H3O+
C
CH3
+
CH3CH2OH + 2 MgBrOH
CH3
2-methyl-2-hexanol (85%) ( a 3º alcohol)
Write a complete mechanism for Grignard reduction of an ester.
ALCOHOLS & PHENOLS
10
Carboxylic acids don’t give alcohols with Grignards because their acidic hydrogen reacts with
the strongly basic Grignard to yield a hydrocarbon and a Mg-salt of the acid. A Grignard is
not as strong a nucleophile as LiAlH4 and the carboxylate anion is not attacked by a Grignard
as it is with the very powerful hydride nucleophile. Actually Grignards are sometimes used
for precisely the purpose of converting an alkyl halide to an alkane via a Grignard reaction.
O
O
CH3CH2
C
+
O
propanoic acid
CH3
MgBr
CH3CH2
-+
C
+
O MgBr
H
CH4
methane
Grignards also add to other compounds that have an electropositive atom, i.e.,
O
C
C
N
SO2R
NO2
NR2
Limitations of the Grignard Reaction: Grignards cannot be prepared when reactive groups are
present along with the halide, e.g., acidic H’s in carboxylic acids.
 Grignards are destroyed (protonated) by even weakly acidic functional groups All of
the groups listed in the table below have a terminal H that is acidic enough to react
with the strongly basic Grignard.
ArCOOH
RCOOH
ArSH
RSH
ArOH
R-OH
amide
-CC-H
ArNH2
RNH2
4
5
7
10
10
16
17
25
~30
35
pKa

Assuming alkyl amines (pKa ~ 35) to be the weakest acid that would react with a
Grignard, calculate the approximate pKb of a Grignard.

Do problems 17.9, 17.10 & 17.11
Sec.17.7
+
H3C
Reactions of Alcohols:
-
..
O
..
+
H
Alcohols, like water, are amphoteric, i.e., they can act as both acids and bases. The pKa and
pKb of simple alcohols are both in the range of 16-19. In alcohols, both the -C and the
hydroxyl-H are + while the hydroxyl-O is  -. The lone pairs of electrons on the hydroxyl-O
make it basic and nucleophilic. The + H makes it weakly acidic.
a) Strong bases can abstract the weakly acidic H from alcohols producing alkoxides
C
O
H
alcohol
(as acid)
ALCOHOLS & PHENOLS
+
B
strong base
C
O
+
+
BH
alkoxide
11
b) In the presence of strong acids, alcohols act as bases and accept protons. This is the same as
what occurs when strong acids are dissolved in water, i.e., the hydroxyl-O accepts a proton
from the acid and H3O+ forms.
C
+
H
O
H
alcohol
(as base)
A
C
H
+
O H
+
A
-
strong acid
c) Good nucleophiles, like HS-, CN-, I-, and Br-, may attack and bond with the -carbon causing
the C-O bond to break, resulting in a substitution. The hydroxyl group, however, is a poor
leaving group in substitution reactions for several reasons. First, the C-OH bond is very strong
(>90 kcal/mol) and is difficult to break. Second, the hydroxyl group must leave as OH- and
charge separation always requires high energy input. Substitution of the OH group is much easier
if the hydroxyl group is first protonated as in reaction b) above. The leaving group is then a
neutral molecule, i.e., H2O.
nucleophilic substitution reaction
-
+
Nu
H
+
O H
C
Nu
+
C
H2O
protonated
alcohol
1. Dehydration of Alcohols to Alkenes:
H
OH
C
C
H+
C
dehydration
C
H2O
+
alkene
alcohol
3 alcohols are dehydrated by warm (50 C) aqueous H2SO4 in THF. Elimination follows
Zaitsev’s rule, producing the more highly substituted alkene.
CH3
+
H
O
H
1-methylcyclhexanol
(3º alcohol)
CH3
+ H
O
H
HSO4
THF
50ºC
1-methylcyclohexene
E1
CH3
+
H
CH3
+
H2O
H
H
HSO4
3º C+
2 and 1 alcohols require severe conditions (conc. H2SO4 & heat!). Recall the dehydration of
cyclohexanol to cyclohexene. Under these conditions, product may be charred or rearrange
(if more highly substituted carbocations can form).
C
C
C OH
20%
H HSO4
50ºC
C
C
+
C
t-butyl alcohol
(3º alcohol)
ALCOHOLS & PHENOLS
C
C
fast E1 rxn.
C
+ H
O
H
C
C
C+
C
C
H
3º C+
HSO4-
C
+
H2O
+
H2SO4
C
2-methylbutene
12
C
C OH
isopropyl
alcohol
(2º alcohol)
C
60%
+
H HSO4
100ºC
C
C
C OH
ethyl alcohol
(1º alcohol)
+ H
O
H
C
C
C+
C
C
+
H2O
+
H2SO4
H2O
+
H2SO4
-
2º C+
HSO4
propene
Unstable 1 C+
requires high temp.
slow
E1 rxn.
C
C H
C
moderate
E1 rxn.
95%
+
H HSO4
170ºC
C
C
+ H
O
H
C
H
H
C+
1º C+
C
HSO4
C
+
ethylene
A safer approach, to dehydrating 1º and 2º alcohols is to react them with phosphorus
oxychloride (POCl3) in pyridine (C5H5N) - a basic amine solvent. The reaction will proceed
even at 0 C. Pyridine (pKb = 5.3) is a basic solvent. The mechanism is E2 (no C+ forms and
no rearrangements occur) .
..
OH
..
:N
..
Cl
+
O
P
Cl
Cl
H
O
+
P
O
H
:N
H
.. :
O
Cl
Cl
P
O
Cl
Cl
cyclopentene
This also works with 3 alcohols (E2) but the reagent is nasty and should be avoided if possible.

Do problem 17.12
2. Conversion of Alcohols into Alkyl Halides (Sec. 17.7):
This is another C-O bond breaking reaction of alcohols. HI, HBr, or HCl react readily with
3 alcohols, moderately with 2 alcohols, and poorly with 1 alcohols. For example, t-butyl
alcohol reacts rapidly with conc. HCl at 25 C forming t-butyl chloride. 1 and 2 alcohols
are unreactive under these conditions but 2º alcohols will react if ZnCl2 catalyst is added.
 These differences provide the basis of a qualitative test (Lucas test) to distinguish alcohols.
Lucas reagent = ZnCl2 dissolved in conc. HCl. Formation of an alkyl chloride from an alcohol
is indicated by the cloudiness that appears when the alkyl chloride separates from the aqueous
solution. 3º, allyl and benzyl alcohols react in seconds (even without ZnCl2). 2º alcohols
react in 1 to 5 minutes (only with ZnCl2). 1º alcohols require from 10 minutes to days to react
unless heated. Note that alcohols must be soluble in Lucas reagent otherwise any alkyl halide
produced will not appear as cloudiness but will simply dissolve in the organic (alcoholic)
layer. Alcohols of not more than 6 carbons are soluble in the Lucas reagent.
ALCOHOLS & PHENOLS
13
conc. (37%)
H
Cl
C
C
C OH
C
C
C
ZnCl2
C
fast SN1 rxn.
C
+ H
O
H
C+
C
C
C
conc. (37%)
H
Cl
C OH
ZnCl2
moderate
SN1 rxn.
isopropyl
alcohol
(2º alcohol)
C
+ H
O
H
C
C
C OH
ZnCl2
ethyl alcohol needs heat
(1º alcohol) slow SN2 rxn.
C
C
H2O
C
Cl-
C+
Cl
C
C
+
H2O
isopropyl
chloride
2º C+
conc. (37%)
H
Cl
C
C
C
+
C
t-butyl chloride
3º C+
t-butyl alcohol
(3º alcohol)
Cl
C
C
C
C
C
-
Cl
1º C+
+ H
O
H
C+
C
not formed
too unstable
Cl-
Cl
C
C
+
H2O
ethyl
chloride
 As in the dehydration reaction studied in the last section, 1 and 2 alcohol reactivity can be
improved by reacting with a reagent which makes the -OH group a better leaving group.
Phosphorus tribromide (PBr3) and thionyl chloride (SOCl2) react quickly by SN2 mechanism.
Whereas reaction with HX is reversible, these reactions proceed to completion.
 3 alcohols will also react quickly with PBr3 and SOCl2 but via an SN1 mechanism. Since
SOCl2 and PBr3 are corrosive, we would normally choose a mineral acid (HCl, HBr or HI) to
produce an alkyl halide from a 3º alcohol.
R OH
+
O
S
Cl
+
Br
ALCOHOLS & PHENOLS
P
Br
R
Cl
(1º alcohol)
R OH
H
-
Cl
O
(1º alcohol)
Br
Br
-
R
+
O
H
+
O
S
Cl
PBr2
R
R
Cl + SO2 + HCl
Br
+
HOPBr2
14
3. Reaction of Alcohols as Acids: (a qualitative lab test for alcohols)
Active metals such as Na, Li, K, Ca, etc. are strong bases (as well as strong reducing agents)
and will deprotonate alcohols. Alcohols act as acids in this case and form alkoxide salts.
R
O
+
H
strong base
weak acid
CH3CH2OH
R
Na
+
-
O
+
1
+
1
/2 H2
/2 H2
alkoxide
CH3CH2O- Na+
Na
+
Na
sodium ethoxide
H3C
H3C
C OH
+
K
C
H3C
/2 H2
potassium isopropoxide
CH3
CH3
+
2 CH3CHCH2OH
Ca
-
+
+
(CH3CHCH2O )2 Ca
calcium diisobutoxide
isobutyl alcohol
CH3
H2
CH3
CH3CCH2OH
+
(CH3CCH2O- )3 Al+3
Al
+
3
/ 2 H2
CH3
CH3
neopentyl alcohol

1
+
H3C
isopropyl alcohol
3
O K+
aluminum trineopentoxide
Write an equation for the reaction of cyclohexanol and lithium. Name the product.
Elimination Often Competes with Substitution:
 Strong dehydrating acids (H2SO4, H3PO4) favor elimination (dehydration) in alcohols.
Because they are strong acids, they readily protonate the alcohol thereby converting a poor
leaving group (OH-) into a better leaving group (HOH), however, the anions produced after
protonation of the alcohol (HSO4- or H2PO4-) are very poor nucleophiles and can’t replace the
leaving group, so elimination (dehydration) occurs.
+
H2SO4 (catalyst)

CH2=CH2 +
(CH3)2CH-OH +
H2SO4 (catalyst)

CH3CH=CH2 + H2O
(elimination)
(CH3)3C-OH
H2SO4 (catalyst)

(CH3)2C=CH2 + H2O
(elimination)
CH3CH2-OH
+
H2O
(elimination)
 Strong non-dehydrating acids (like HI, HBr and HCl) also readily protonate an alcohol
creating a better leaving group (HOH) but with the difference that the resulting Nu:-’s (like I,
Br-, and Cl-), are better Nu:-’s and readily replace the leaving group which results in
substitution instead of elimination.
CH3CH2-OH
+
HBr
(CH3)2CH-OH +
HBr 
(CH3)3C-OH
HBr
+
ALCOHOLS & PHENOLS

CH3CH2-Br
(CH3)2CH-Br

+ H2O
+ H2O
(CH3)3C-Br
+ H2O
(substitution)
(substitution)
(substitution)
15
4. Oxidation of Alcohols (Sec. 17.8):
This represents the opposite of reduction of carbonyls to alcohols.
(loss of H or gain of O)
O
C
C
C
H
C
oxidation
reduction
O
C
C
C
(loss of O or gain of H)
 1 alcohols have 2 -hydrogens and can either lose one of them to yield aldehydes or lose
both of them to form carboxylic acids (depending on the oxidant strength)
 2 alcohols can lose their only -hydrogen to yield ketones or under severe oxidation
conditions, can be cleaved to carboxylic acids.
 3 alcohols don’t have any -hydrogens and so don’t normally oxidize except under severe
oxidation conditions in which case they can dehydrate to alkenes which are subsequently
oxidized and cleaved to carboxylic acids.
 Oxidants include acidic or basic aq. KMnO4, Na2Cr2O7 in HAc, NaOCl in aq. HAc, CrO3 in
aq. H2SO4 + acetone (Jones reagent), CrO3 in pyridine (Collins reagent), or PCC, i.e.,
pyridinium chlorochromate, (C5H5NCrO3Cl) in dichloromethane solvent.
a) 1 alcohols are oxidized only to aldehydes by the anhydrous oxidants (Collins reagent or
PCC) which are mild. The aqueous oxidants will oxidize 1 alcohols to carboxylic acids.
mild oxidation
(oxidants in non aq. solvents)
PCC (in CH 2Cl 2)
Collins reagent (CrO 3 in pyridine)
OH
R
O
R
C
H
aldehyde
CH2
1º alcohol
O
moderate or strong oxidation
R C OH
(oxidants in aq. solvents)
Jones reagent (CrO 3 in aq. H 2SO4 & acetone)
carboxylic
acid
KMnO 4, HNO 3, etc.
b) 2 alcohols yield ketones using any of the above oxidants except the strongest (hot KMnO4,
hot H2CrO4, or hot conc. HNO3) which dehydrate them to alkenes and subsequently cleave
the alkenes to carbonyl compounds (See Ch. 7 on alkene cleavage)
OH
R
CH R
2º alcohol
O
mild to moderate oxidation
(in non aq. solvents or any cold aq. solvent) R C R
PCC (in CH2Cl2)
ketone
Collins reagent (CrO3 in pyridine)
Jones reagent (CrO3 in aq. H2SO4 & acetone)
cold acidic or basic KMnO4, HNO3, etc.
O H
O
severe oxidation
R C R
R C R
(hot aq. KMnO4 or HNO3)
ketone
enol
O
2 R C
OH
carboxylic acid
c) 3 alcohols are not oxidized by any of the above oxidants except hot KMnO4 or hot conc.
HNO3 which dehydrate them to alkenes and subsequently cleave the alkenes to carbonyl
compounds (See Ch. 7 on alkene cleavage). 3 alcohols are easiest to dehydrate to alkenes.
ALCOHOLS & PHENOLS
16
no rxn.
any anhydrous or cold aq. oxidant
OH
R
C
R
R
3º alcohol

O
severe oxidation
(hot aq. KMnO 4 or HNO 3)
R
dehydration
CH R
alkene
2 R C
OH
carboxylic acid
Do problems 17.13 & 17.14
Identifying Alcohols by Oxidation:
1. Jones Reagent:
Chromic acid is a clear orange solution of Cr+6 in aq. H2SO4. When it is reduced (e.g., when
it oxidizes an alcohol) the solution turns blue-green due to the formation of Cr+3 ion. 1 and
2 alcohols are reduced by Jones reagent that changes from orange to green. This is a simple
qualitative test that can distinguish 3 alcohols from 1 and 2 alcohols and aldehydes.
Blood Alcohol Screening:
In its simplest form, a blood alcohol-screening test consists of a sealed glass tube containing a
potassium dichromate reagent impregnated on silica gel. To administer the test, the ends of
the tube are broken off, a mouthpiece is fitted to one end, and the other end is inserted into the
neck of a plastic bag. The person being tested then blows into the mouthpiece until the plastic
bag is inflated.
As breath containing ethanol vapor passes through the tube, reddish orange dichromate ion is
reduced to green Cr+3 ion. The concentration of ethanol in the breath is then estimated by
measuring how far the green Cr+3 ion color extends along the length of the tube. When the
green color extends beyond the halfway point, the person is judged as having a sufficiently
high breath alcohol content to warrant more precise testing.
The Breathalyzer, a more precise testing device, operates on the same principle as the
simplified breath-screening test. In a Breathalyzer test, a measured volume of breath is
bubbled through a solution of Jones reagent and the color change is measured
spectrophotometrically.
These tests measure alcohol in the breath. The legal definition of being under the influence of
alcohol, however, is based on blood alcohol content. The chemical correlation between these
two measurements is that air deep within the lungs is in equilibrium with blood passing through
the pulmonary arteries, and an equilibrium is established between blood alcohol and breath
alcohol. It has been determined by simultaneous tests that 2100 mL of breath contains the same
weight of ethanol as 1.00 mL of blood. See W. C. Timmer, J. Chem. Ed., 63:897 (1986).
2. The Iodoform Reaction:
The iodoform reaction, although of little synthetic value is often used to determine whether an
alcohol contains a particular structural unit. The alcohol is treated with a solution of iodine
and a solution of sodium hydroxide.
NaOH + I2  NaOI (sodium hypoiodite)
ALCOHOLS & PHENOLS
17
The product of the reaction of the suitable alcohol and the reagent is iodoform (CHI3),
which is a light yellow solid with a mp of 119 C. In order for the alcohol to give a
positive iodoform reaction, it must 1) be readily oxidized and 2) have methyl group
attached to the carbon containing the alcohol group (the -carbon = the carbinol carbon).
Of all the 1 alcohols, only ethanol, CH3-CH2-OH, meets the structural requirement.
2 alcohols are readily oxidized and those that have a methyl group attached to the
carbinol carbon atom give a positive iodoform reaction ...
e.g., CH3-CH(OH)-CH3
and
CH3-CH2-CH(OH)-CH3
3 alcohols, although they may have two and in the case of t-butyl alcohol, three methyl
groups attached to the carbinol carbon, do not give the iodoform reaction because they are
not oxidized under the reaction conditions.
The reaction involves oxidation, iodination, and cleavage. Consider ethanol ....
O
OXIDATION:
+
CH3 CH2 OH
NaOI
O
IODINATION:
+
CH3-C-H
O
+
CH3-C-H
3 NaOI
+
CI3-C-H
3 NaOH
O
CLEAVAGE:
+ H2 O
NaI
+
CI3-C-H
NaOH
CHI3
O
+
+
-
Na O-C-H
The reaction involving 2-butanol and NaOI proceeds as follows ...
OXIDATION:
CH3 CH2 CHCH3
+
NaOI
+
NaI
+
CH3 CH2 CCH3
3 NaOI
CH3 CH2 CCI3
3 NaOH
+
O
O
+
CLEAVAGE:
CH3 CH2 CCI3
+ H2 O
O
OH
IODINATION:
CH3 CH2 CCH3
+
NaOH
CHI3
+
O
-
Na O-C-CH2-CH3
O
Question: How could one differentiate between 2-pentanol and 3-pentanol? Consider the
Lucas test, the Jones reagent test and the Iodoform reaction.
It is apparent from the foregoing reactions that acetaldehyde and methyl ketones will also give
a positive reaction with the iodoform test.
Br2 and Cl2 also react with methyl alcohols and methyl ketones to yield bromoform (CHBr3)
and chloroform (CHCl3), respectively. Haloform is the general term to describe CHX3; hence
the reaction is often referred to as the 'haloform' reaction. Because bromoform and
chloroform are nondistinctive liquids, their formations are not useful for identification tests.
ALCOHOLS & PHENOLS
18
5. Reduction of Alcohols to Alkanes:
 Alcohols can be reduced in 2 steps by first dehydrating to an alkene (with a strong
dehydrating acid such as H2SO4 or H3PO4 and subsequently hydrogenating the alkene to an
alkane.
 Another method is to first convert the alcohol to a tosylate ester and then displace the
tosylate group with H:- using LiAlH4.
H
OH + Cl
O
O
H
pyridine
S
CH3
O
O
cyclopentanol
LiAlH4
S
CH3
O
tosyl chloride, TsCl
cyclopentane
cyclopentyl tosylate
The student should be able to write a mechanism for this reaction.
6. Protection of Alcohols (Sec. 17.9):
Alcohol groups can be protected during synthesis reactions by reacting the alcohol with
trimethylsilyl (TMS) chloride forming a TMS ether which is not attacked by Grignards. The
TMS group can be later removed by aqueous acid or fluoride ion.
Mg
(CH3CH2)3 N
HOCH2CH2Br +
(CH3)3 Si O CH2CH2Br
(CH3)3SiCl
(CH3)3 Si O CH2CH2MgBr
ether
protect
Grignard reagent
O
OH
(CH3)3 Si OH
+
CH3CH
2.
H3O
+
OH
+
H3O
HO CH2CH2 CHCH3
1.
(CH3)3 Si O CH2CH2 CHCH3
remove protecting group
ALCOHOLS & PHENOLS
19
PHENOLS Sec. 17.10 & 11
We have already studied the synthesis of phenol by high temperature reaction of aromatic sulfonic
acids with NaOH.
: :
O
..
O
..
H
H
..
OH
..
H
1. NaOH, 300ºC
2. H3O+
H
:O :
H
H
S
OH
H
H
H
H
Also recall that phenols are also produced by nucleophilic aromatic substitution (NAS) of
halobenzenes bearing one or more electron withdrawing groups (-NO2) ortho or para to the halogen.
H
H
H
..
Cl
.. :
H
H
NaOH
NO2
OH
H
-
:
H
H
-
H
NO2
..
Cl
.. :
H
-
.. : Cl :
H
H
NO2
H
NaOH
H
OH
+
H3O
OH
NO2
H
H
.. +
O
.. : Na
Reactions of Phenols:
1. Acidity: The hydroxyl hydrogen in phenols is acidic enough to react completely with dilute
NaOH. The phenoxide ion is resonance stabilized.
 Draw the mechanism.
 Calculate pKeq, the extent of the forward reaction and the pKb of phenoxide.
 Draw resonance structures of phenoxide anion.
O
O
H
+
+
Na
+
+
-
Na OH
H2O
sodium phenoxide
pKa = 9.9
2. Electrophilic Aromatic Substitution (EAS): The OH group is an electron donor to the aromatic
ring with the result that phenols readily undergo EAS in their o- and p-positions.
 Pentachlorophenol, a wood preservative, is prepared via EAS by reaction of phenol & excess Cl2.
 Butylated hydroxytoluene (BHT), an antioxidant food preservative is prepared by Friedel-Crafts
alkylation of p-methylphenol (p-cresol) with 2-methylpropene in acid catalyst.
 Butylated hydoxyanisole (BHA), a preservative in butter, is prepared by alkylation of
p-methoxyphenol.
OH
Cl
OH
OH
Cl
(CH3)3 C
C(CH3)3
C(CH3)3
Cl
Cl
Cl
pentachlorophenol
(PCP)
CH3
BHT
2,6-bis(1,1-dimethylethyl)-4-methylphenol
O
CH3
BHA
2-(1,1-dimethylethyl)-4-methoxyphenol
Do Problems 17.16 & 17.17.
ALCOHOLS & PHENOLS
20
3. Oxidation of Phenols: (to Quinones) Phenols do not undergo oxidation like alcohols since they
do not have any -carbon hydrogens. Instead, in the presence of strong oxidants such as
Na2Cr2O7 [or Fremy’s salt, potassium nitrosodisulfonate, (KSO3)2NO], phenols are oxidized to
quinones (2,5-cyclohexadiene-1,4-dione).

Quinones are reversibly reduced to hydroquinones by reducing agents such as NaBH4 or SnCl2.
O
OH
OH
SnCl2, H2O
(KSO3)2NO
H2O
(KSO3)2NO
O
OH
quinone
hydroquinone
(1,4-benzenediol)
The redox properties of quinones are vital to respiration of all living cells. Ubiquitous compounds
called ubiquinones (also called coenzymes Q) react with O2 to oxidize NADH (nicotinamide adenine
dinucleotide reduced) to produce NAD+ (oxidized form), water and energy.
Phenol and various methylated phenols are used as antiseptics. Phenol itself is corrosive and toxic;
ingesting only about 1 gram is sufficient to cause death.
The largest industrial use of phenol is in the manufacture of Bakelite, a heat resistant polymer made
by polymerizing phenol with formaldehyde. This same polymer is also used as an adhesive in
bonding plywood.

Do the following end of chapter problems:
17.21, 22, 24, 27-35, 37, 38, 41, 48 and 54.
ALCOHOLS & PHENOLS
21
THIOLS Sec. 17.12
 Ethers are obtained if both H’s of water are replaced by two alkyl groups (R-OR’), or by one
alkyl and one aromatic group (R-O-Ar), or by two aromatic groups (Ar-O-Ar’).
 Thiols (R-SH) are sulfur analogs of alcohols, i.e., S replacing O.
S is directly below O in Group VI of the periodic table. Many organic compounds containing O
have S-analogs. Generic sulfur compounds are shown ....
R
R-SH
thiols
R-S-R
Ar-SH
R-S-R
sulfoxide
O
S
R-S-R
O
sulfone
R-S-R
+
disulfides
thiophenols
thioethers
O
R-S-S-R
trialkylsulfonium ions
O
O
R-C-R
R-S-OH
R-S-OH
thioketone
sulfinic acid
O
sulfonic acid
 The S-analog of an alcohol (R-OH) is an ‘alkanethiol’ or a ‘thiol’ (R-SH). [‘theion’, Greek,
brimstone - an older name for sulfur].
 In the common nomenclature system, thiols are called ‘mercaptans’. [‘mercurinium captans’,
Latin, means capturing Hg]. Mercaptans react with Hg+2 ions and the ions of other heavy
metals to form precipitates. The compound CH2(SH)-CH(SH)-CH2OH, known as ‘BritishAnti-Lewisite’ (BAL) was developed as an antidote for poisoning, e.g., As, Hg, heavy metals.
 The ‘-SH’ group has several names 1) mercapto group 2) thiol group 3) sulfhydryl group
Nomenclature:
 IUPAC names for thiols are named like alcohols. The suffix ‘-thiol’ is attached to the alkane
name. When the -SH group is a substituent, it is identified with the prefix "mecapto" or "thio"
on the parent name. They are literally named as ‘alkanethiols’.
 Common names of simple thiols are like those for simple alcohols except that ‘alcohol’ is
replaced by ‘mercaptan’and become ‘alkyl mercaptans’.
CH3SH
(I) methanethiol
CH3CH2CH2SH
1-propanethiol
(c) methyl mercaptan n-propyl mercaptan
CH2=CH-CH 2-SH
BrCH2CH2CH2CH2CH2SH
5-bromo-1-pentanethiol
2-propen-1-thiol
------------------
allyl mercaptan
O
OH
C
CH3
CH 3CH 2=CHCH 2-SH
ALCOHOLS & PHENOLS
CH3CHCH2CH2SH
HS-CH 2CH 2-OH
SH
SH
22
(I)
2-butene-1-thiol
3-methyl-1-butanethiol
2-mercaptoethanol
2-thioethanol
(c)
--------------
isopentyl mercaptan
------------
cyclohexanethiol
3-mercaptobenzoic acid
cyclohexyl mercaptan
m-mercaptobenzoic
ALCOHOLS & PHENOLS
acid
23
Odor Properties:
The most distinctive characteristic of thiols is their rank odor.
 H2S has the odor of rotten eggs
 3-methyl-1-butanethiol and 2-butene-1-thiol are the main ingredients in skunk odor.
 1-propanethiol is the odor of freshly chopped onions
 allyl mercaptan is a major contributor to the odor and flavor of garlic
 methanethiol is added to natural gas (odorless methane) to give it an odor for detecting leaks.
The human nose is very sensitive to these compounds and can detect their presence at ~ 0.02 ppb
in air. Higher MW thiols, being less volatile, are less odiferous.
Boiling Points:
S-atoms are less EN than O-atoms and thus form weaker H-bonds than alcohols. Thus low MW
thiols have lower bp’s than corresponding alcohols ...
CH3CH2OH (78 C)
CH3OH (65 C)
CH3CH2SH (37 C)
CH3SH (6 C)
Acidity:
The bond dissociation energy of the S-H bond of thiols (~ 80 kcal/mol) is significantly less than
for O-H bonds (~100 kcal/mol). In addition, S’s large size makes it more polarizable and hence
better able to stabilize a negative charge than oxygen. As a result, thiols are more readily
deprotonated by bases (i.e., more acidic) than alcohols ...
..
..S
R
+
H
Na+ OH-
R
.. _
..S :
Na+
+
H2O
compound
pKa
compound
pKa
H2O
15.7
H2S
7.0
CH3OH
15.4
CH3SH
~8
CH3CH2OH
16.0
CH3CH2SH
8.5
Thiols are sufficiently strong acids that when dissolved in aq. NaOH, they are converted
completely to alkylsulfide salts (also called alkanethiolates).
CH3CH2
..
..S
H
+
Na+ OH-
CH3CH2
.. _
..S :
Na+
+
H2O
sodium ethyl sulfide
sodium ethylthiolate
Write the equations for the reaction of ethanethiol with NaOH (aq) and with NaHCO3, calculate
pKeq and the extent of these reactions.
ALCOHOLS & PHENOLS
24
Solubility:
Like H2S and its salts (Na+SH-), thiols form water-insoluble salts with most heavy metals.
2 RSH + Hg+2  Hg(SR)2 + 2 H+
2 RSH + Pb+2  Pb(SR)2 + 2 H+
(yellow precipitate)
The yellow precipitate is a positive test for a thiol.
Preparation of Thiols:
Since S is large and polarizable, alkyl sulfide anions (RS-) and hydrosulfide anions (HS-) are
good nucleophiles. These anions readily replace halogens in alkyl halides via SN2 reactions.
H2S + NaOH  Na+HS- + HOH
CH3-Br + Na+HS-  CH3-SH + NaBr
The thiol product is also acidic and reacts with more base to produce sodium methyl sulfide
which is a good nucleophile and can itself substitute for Br in another molecule of alkyl halide
producing a dialkyl sulfide.
CH3-SH + NaOH  Na+CH3S- + HOH
Na+CH3S- + CH3-Br  CH3-S-CH3 + NaBr
To avoid the 2nd reaction, a large excess of H2S may be used.
Oxidation of Thiols:
When alcohols are treated with oxidizing agents, oxidation takes place at the weaker C-H bond
(~100+ kcal/mol) rather than at the stronger O-H bond (~ 105+ kcal/mol).
H
O
[O]
CH3 C
OH
CH3 C
OH
H
In thiols, the weaker S-H bond (~ 80 kcal/mol) is broken during oxidation.
Mild oxidizing agents such as I2, Br2, and potassium ferricyanide [K3Fe(CN)6], break the S-H
bond and cause the formation of a disulfide containing an S-S linkage (an oxidative coupling
reaction).
I2
CH3CH2 S
2 CH3CH2 SH
Zn, HCl
S CH2CH3
+
2 HI
diethyl disulfide
The reaction can be reversed with reducing agents such as Zn in HCl.
Molecular oxygen can also cause oxidative coupling and thiols must be protected from exposure
to air to avoid this reaction.
ALCOHOLS & PHENOLS
25
Stronger oxidants such as KMnO4 and H2O2 yield more highly oxidized products such as sulfonic
acids. A sequence of oxidation products is shown...
[O]
RSH
+
R SOH
sulfinic acid
+ 2 H2O
thiol
O
[O]
R SOH +
O
+
4 e-
O
R SOH
H2O
4 H+
+
2 H+
+
2 e-
O
sulfonic acid
Note that as a 3rd-row element with d-orbitals, S’s valence shell can be expanded to accommodate
more electrons than allowed by the octet rule. Some S-compounds accommodate 10 or even 12
valence electrons, e.g., SF6.
A sulfide (R-S-R) can be oxidized to a sulfoxide or a sulfone depending upon the reaction
conditions.
H+, 25 ºC
O
CH3 S CH3
CH3 S CH3
+
dimethyl sulfoxide (DMSO)
H2O2
O
dimethyl sulfide
+
H , 100 ºC
CH3 S CH3
dimethyl sulfone
O
DMSO is a powerful solvent for both inorganic and organic ions. It has a high dielectric constant
(49D), i.e., it is highly polar, yet it does not H-bond. (Why?) DMSO solvates cations but not
anions, leaving anions as bare, reactive nucleophiles-excellent for substitution reactions. DMSO
readily penetrates the skin and has been used to promote dermal absorption of drugs; but it can
also cause absorption of dirt and poisons.

Do problems 17.18 & 17.19
ALCOHOLS & PHENOLS
26
Homework Problems from McMurry Organic Chemistry
In the following tables are listed; problems ‘you should be able to solve’ and ‘problems you are
not responsible for’. If you haven’t time to do all of the former questions, be sure to do a
representative number, i.e., a couple of each kind until you are satisfied that you can solve these.
It is recommended that you review the notes (text and class notes) and then do the problems.
Until you have attempted the problems you really don’t know if you know what you should
know!
Homework Problems from Ch. 17 (Alcohols & Thiols)
Problems you should be able to solve
1-5
7-10
11 a), c)
12-14
18-19
20-23
24 a) - e)
25
27-28
30-31
33 a) - c)
34
38
39 b) - d)
52
Problems you are not responsible for
6
11 b)
15-17
24 f)
26
29
32
33 d)
35-37
39 a)
40 - 51 and 53 - 55
The horizontal line in the table separates the in-chapter problems from the end-of-chapter
problems. The answers to the in-chapter problems are the back of the text. The solutions to all
end-of chapter problems are found in the solution manual for the McMurry textbook. Several
copies are on sale in the bookstore and one copy is kept on reserve in the college library.
ALCOHOLS & PHENOLS
27