Alcohols, Phenols and Thiols,
and ethers
Nomencalture of alcohols
Use the end ol
Examples
CH3OH
CH3CH2OH
CH3CH2CH2OH
Methanol
Methyl alcohol
Ethanol
ethyl alcohol
1-propanol
propyl alcohol
CH3CHCH3
OH
2-propanol
isopropyl alcohol
CH3
H3C
CH2OH
H3C
2-methyl-1-propanol
isobutyl alcohol
H3C
C
OH
CH2 = CH - CH2OH
CH3
2-methyl-2-propanol
tert-butyl alcohol
2-propen-1-ol
allyl alcohol
OH
OH
HO
cyclopentanol
OH
cis-1,2-cyclopentandiol
2-phenylethanol
OH
OH
H3C
C
C
CH2OH
C
H2
NO2
3-pentyn-1-ol
COOH
p-nitrophenol
phenol
CHO
OH
OH
o-hydroxybenzoic acid
salicylic acid
m-hydroxybenzaldehyde
Hydrogen bonding in alcohols and phenols
• Alcohols and phenols form hydrogen bonds, and hence
they have relatively high boiling points. This also makes
the lower alcohols miscible with water. As the R group
becomes larger, the solubility of alcohols in water
decreases dramatically.
• Hydrogen bonding
• Hydrogen bonding occurs between molecules where you
have a hydrogen atom attached to one of the very
electronegative elements - fluorine, oxygen or nitrogen.
Acidity of Alcohols
Acids are proton donors.
The acidity increases as the negative charge at the OH decreases
(delocalized):
a)
phenols are more acidic than Alcohols due to resonance effect
(delocalization of the negative charge)
Types of alcohols
H
H
H C OH
H
Methyl alcohol
H3C
C
OH
CH3
CH3
H3C
C
CH3
OH
Isopropyl alcohol tert- butyl
alcohol
 Primary alcohols (1°): contains an OHfunctional group that has one or no carbon
atoms attached to it; Example: Methyl alcohol
 Secondary Alcohols (2°): contains an OHfunctional group that has two carbon atoms
attached to it; Example: Isopropyl acohol.
 Tertiary Alcohols (3°): contains an OHfunctional group that has three carbon atoms
attached to it.
Methyl Alcohol (Methanol)
Known as wood alcohol due to preparation
from the distillation of wood.
Commercially
prepared
from
CO
according to:
CO + 2H2  CH3OH (Pt catalyst, heat)
CH3OH is an important solvent.
CH3OH is toxic. (ingestion of 15 ml 
blindness, 30 ml  death).
Should never be inhaled nor applied to the
skin. (good absorption from both tissues)
Ethyl Alcohol (Ethanol)
 In hospital the word alcohol means ethyl alcohol.
 Can be prepared from the fermentation
blackstrap molasses (residues resulting from the
purification of can sugar) under the influence of
yeast enzymes.
C12H22O11 + H2O  4 C2H5OH + CO2
 Grain alcohol  grain starch  sugar by malt 
fermentation.
 Synthetic preparation from ethene
(Catalyst: Silicon dioxide)
Ethyl Alcohol (Ethanol)
 The property of ethanol as an antiseptic agent is
based on its ability to denaturate proteins.
 Cave: the antiseptic property of 70% ethanol
solution (in water) is better than 100 % ethanol.
 Explanation: 100 % ethanol leads to the
coagulation (‫ )تخثر‬of proteins in the cell wall of
bacteria (or other one-cell organisms), which
builds a ring preventing further ethanol to enter
the inside of the bacteria and to coagulate other
proteins there. 70% ethanol, however,
coagulates proteins to a slower rate allowing
ethanol to penetrate (‫ )نفذ الى‬the cell inside of
bacteria and coagulate proteins there.
Ethyl Alcohol (Ethanol)
 Ethanol ( better than water) can be used for
sponge baths to reduce fever (‫ )حرارة‬from
patients. When placed on skin  rapid removal.
Evaporation needs heat, which comes from
patient’s skin  lowering temperature. (cave:
ethanol is flammable(‫))قابلة لالشتعال‬
 Ethanol is a solvent for many substances. A
solutions are called tinctures (Example: iodine
tincture).
 Alcohol is used as a beverage depression of
nervous system, removal of individual’s
inhibition. Excessive use  cirrhosis (liver
destruction)
Isopropyl alcohol
OH
H3C
CH3
 According to IUPAC isopropyl alcohol is called
2-propanol.
 Is toxic, and therefore should not be taken
internally.
 It does not get into the skin. Therefore, it can be
used as rubbing alcohol.
Ethylene glycol
HO
OH
 IUPAC (International Union for Pure and Applied
Chemistry) name: 1,2 ethanediol
 Ethylene glycol is a dihydric alcohol:
 It has a high boiling point due to extensive
hydrogen bonding.
 It is completely miscible with water.
 It is extremely toxic if taken internally
(Metabolism to oxalic acid  Crystallization as
calcium oxalate  kidney stones).
 Antidote: administration of high levels of ethanol
Why? High levels cause the liver to metabolize
the ethyl alcohol rather than the toxic alcohol.
 Uses: Skin moistures, anti freeze in cars.
HO
OH
Glycerol
OH
 IUPAC name: glycol 1,2,3 propanetriol
 Glycerol is a trihydric alcohol
 Important constituent of body lipids.
 Byproduct by the manufacture of soap.
 Uses: preparation of cosmetics, hand lotions,
suppositories, in rubber tubing and stoppers,
preparation of nitroglycerin.
 Nitroglycerin (Glycerin + Nitric acid) is an
explosive but also an important medication for
the treatment of heart pain by dilatation of
coronary arteries better supply of blood of
heart muscle.
OH
CH3
Other alcohols:Menthol
CH3
H3C
Menthol is a cyclic compound.
It has a cooling refreshing effect, when
rubbed on the skin.
It is used in cosmetics, shaving lotions,
cough drops, and nasal sprays.
Reactions of alcohols
1. Dehydration:
OH
H3C
H2SO4
180°C
Ethene
Ethanol
H2SO4
+
180°C
OH
2-pentanol
2-penten
1-penten
Reactions of alcohols
2. Formation of ethers: using H2SO4. The
conditions are, however, different from
those used for the formation of alkenes.
3. Oxidation: Alcohol  Aldehyde 
Carboxylic acid  CO2 + H2O.
Note:
a. Secondery alcohols  Ketones
b. Tertiary alcohols  (under ordinary
conditions)
4. Formation of esters: Alcohol +
carboxylic acid Ester + H2O
Thiols
H3C
HS
SH
Methanethiol
methylmercaptan
2-propanethiol
isopropylmercaptan
 Thiols are sulfur analogs to alcohols but contain –
SH functional group in place of an –OH group.
 Nomenclature:
-Add the adding thiol to the name of the parent
hydrocarbon
-The e-ending of the parent hydrocarbon is not
deleted.
-Common Names: Alkyl group + the word
mercaptan.
Thiols
 Thiols have a disagreeable odor (Onion[1propanethiol, garlic, added to natural gas to
enable better detection).
 They do not exhibit hydrogen bonding  lower
boiling point than the corresponding alcohols.
 They are less soluble in water than corresponding
alcohols.
 Thiols are important in enzymes involved in
carbohydrate metabolism.
 Preparation: heating of alkyl halide * Sodium
hydrogen sulfide:
Cl
+ NaHS
SH
+ NaCl
Thiols
 Thiols are easily oxidized to disulfides
O2
S
R
SH
S
SH + R
R
 Example for such an oxidation from the
biochemistry:
R
 Disulfide bonds are involved in the formation of
the tertiary structures of proteins.
Phenols
 Benzene with OH group  Phenols.
 Phenols are generally like alcohols but they are
weak acids and alcohols are not.
 Phenol + NaOH  Sodium phenoxide + H2O
ONa
OH
+
NaOH
+
H2O
Phenol is posinous if taken internally, and externally
it causes deep burns on the skin.
Antidote on the skin: 50 % alcohol, glycerin, sodium
bicarbonate solution, water.
Phenol is a disifictant for surgical instruments,
clothing, toilts and sinks.
Phenol is used in the manufacture of dyes (‫)األصباغ‬
and plastics
Phenols
 Phenol is a standard reference for germicidal
(‫ )مبيد للجراثيم‬activity disinfectants (‫)مطهر‬.
 Phenol coffecient 5 = 1% desinfectant = 5%
Phenol solution.
 Cresol (mixture) is a better antiseptic(‫)مطهر‬
than phenol but should be used only
OH
externally.
OH
OH
CH3
CH3
o-Cresol
m-Cresol
CH3
p-Cresol
Phenols
Hexyl resorcinol is a better antiseptic and germicide
than resorcinol and is used in mouth washes.
Butylated hydroxy anisol (BHA)and butylated
hydroxy toluene (BHT) are used as food
preservative (cave: allargy).
OH
OH
CH3
H3C
BHA
O
CH3
OH
OH
CH3
Hexyl resorcinol
CH3
H3C
H3C
BHT
Ethers
Properities of ethers
No hydrogen bonds  low boiling points
 easily moved and recovered
Inert (do not react with other substances)
 good solvents  Extraction of organic
material.
 Very flammable (care must be taken)
Formation of peroxides if left in the lab
for long time (extermely explosive)  not
allowed to stand exposed to air for long
period of time.
Nomenclature
IUPAC: If different alcohols are reacted a mixed
ether is formed; Mixed ethers are named as
alkoxy derivatives (‫ )المشتقات‬of hydrocarbons with
the shorter chain named as the alkoxy group and
the longer chane as the alkane.
Common system: Mixed ethers are named by
listing the alkyl groups followed by the word
ether.
O
H3C
CH3 H3C
Methoxy propane
Methyl propyl ether
O
Diethyl ether
Ethyl ether
CH3
Uses
Ethylether has been used as anesthetic (‫)مخدر‬
for long time (muscle relaxant (‫)ارتخاء العضالت‬, little
effect on respiration rate, blood pressure, pulse
rate). However: flammable, irritant to the
membranes of the respiratory tract, nausea (‫)غثيان‬.
 Replaced by non flammable enflurane and
isoflurane
F
Cl
Cl
F
O
F
F
F
F
O
F
F
F
Enflurane
F
Isoflurane