Chapter 10
Structure and Synthesis
of Alcohols
Jo Blackburn
Richland College,Dallas,TX
Dallas County Community College District
2003,Prentice Hall
Organic Chemistry,5th Edition
L,G,Wade,Jr.
Chapter 10 2
Structure of Alcohols
Hydroxyl (OH) functional group
Oxygen is sp3 hybridized,
=>
Chapter 10 3
Classification
Primary,carbon with –OH is bonded to
one other carbon.
Secondary,carbon with –OH is bonded
to two other carbons.
Tertiary,carbon with –OH is bonded to
three other carbons.
Aromatic (phenol),-OH is bonded to a
benzene ring.
=>
Chapter 10 4
Classify these:
C H 3 C H
C H 3
C H 2 O H C H 3 C
C H 3
C H 3
O H
O H
C H 3 C H
O H
C H 2 C H 3=>
Chapter 10 5
IUPAC Nomenclature
Find the longest carbon chain
containing the carbon with the -OH
group.
Drop the -e from the alkane name,add -
ol.
Number the chain,starting from the end
closest to the -OH group.
Number and name all substituents,=>
Chapter 10 6
Name these:
C H 3 C H
C H 3
C H 2 O H
C H 3 C
C H 3
C H 3
O H
C H 3 C H
O H
C H 2 C H 32-methyl-1-propanol
2-methyl-2-propanol
2-butanol
O H
B r C H
3
3-bromo-3-methylcyclohexanol
=>
Chapter 10 7
Unsaturated Alcohols
Hydroxyl group takes precedence,Assign
that carbon the lowest number.
Use alkene or alkyne name.
4-penten-2-ol (old)
pent-4-ene-2-ol
(1997 revision of IUPAC rules)
=>
C H 2 C H C H 2 C H C H 3
O H
Chapter 10 8
Naming Priority
Acids
Esters
Aldehydes
Ketones
Alcohols
Amines
Alkenes
Alkynes
Alkanes
Ethers
Halides
=>
Chapter 10 9
Hydroxy Substituent
When -OH is part of a higher priority class of
compound,it is named as hydroxy.
Example:
C H 2 C H 2 C H 2 C O O H
O H
4-hydroxybutanoic acid
also known as GHB
=>
Chapter 10 10
Common Names
Alcohol can be named as alkyl alcohol.
Useful only for small alkyl groups.
Examples:
C H 3 C H
C H 3
C H 2 O H C H
3 C H
O H
C H 2 C H 3
isobutyl alcohol sec-butyl alcohol
=>
Chapter 10 11
Naming Diols
Two numbers are needed to locate the two
-OH groups.
Use -diol as suffix instead of -ol.
H O O H
1,6-hexanediol
=>
Chapter 10 12
Glycols
1,2 diols (vicinal diols) are called glycols.
Common names for glycols use the name of
the alkene from which they were made.
C H 2 C H 2
O H O H
C H 2 C H 2 C H 3
O H O H
1,2-ethanediol
ethylene glycol
1,2-propanediol
propylene glycol
=>
Chapter 10 13
Naming Phenols
-OH group is assumed to be on carbon 1.
For common names of disubstituted phenols,
use ortho- for 1,2; meta- for 1,3; and para- for
1,4.
Methyl phenols are cresols.
O H
C l
3-chlorophenol
meta-chlorophenol
O H
H 3 C
4-methylphenol
para-cresol
=>
Chapter 10 14
Physical Properties
Unusually high boiling points due to
hydrogen bonding between molecules.
Small alcohols are miscible in water,but
solubility decreases as the size of the
alkyl group increases.
=>
Chapter 10 15
Boiling Points
=>
Chapter 10 16
Solubility in Water
Solubility decreases as the size
of the alkyl group increases.
=>
Chapter 10 17
Methanol
―Wood alcohol‖
Industrial production from synthesis gas
Common industrial solvent
Fuel at Indianapolis 500
Fire can be extinguished with water
High octane rating
Low emissions
But,lower energy content
Invisible flame =>
Chapter 10 18
Ethanol
Fermentation of sugar and starches in grains
12-15% alcohol,then yeast cells die.
Distillation produces ―hard‖ liquors
Azeotrope,95% ethanol,constant boiling
Denatured alcohol used as solvent
Gasahol,10% ethanol in gasoline
Toxic dose,200 mL ethanol,100 mL methanol
=>
Chapter 10 19
2-Propanol
―Rubbing alcohol‖
Catalytic hydration of propene
=>
C H 2 C H C H 2 H 2 O 1 0 0 - 3 0 0 a t m,3 0 0 癈c a t a l y s t+ C H 3 C H
O H
C H 3
Chapter 10 20
Acidity of Alcohols
pKa range,15.5-18.0 (water,15.7)
Acidity decreases as alkyl group
increases.
Halogens increase the acidity.
Phenol is 100 million times more acidic
than cyclohexanol!
=>
Chapter 10 21
Table of Ka Values
=>
CH3 OH
Chapter 10 22
Formation of Alkoxide
Ions
React methanol and ethanol with sodium
metal (redox reaction).
C H 3 C H 2 O H + N a C H 3 C H 2 O N a + 1 / 2 H 2
React less acidic alcohols with more
reactive potassium,
+ K ( C H 3 ) 3 C O K + 1 / 2 H 2) 3 C O H( C H 3
=>
Chapter 10 23
Formation of Phenoxide
Ion
Phenol reacts with hydroxide ions to form
phenoxide ions - no redox is necessary.
O H
+ OH
O
+ HOH
pKa = 10 pKa = 15.7
=>
Chapter 10 24
Synthesis (Review)
Nucleophilic substitution of OH- on alkyl
halide
Hydration of alkenes
water in acid solution (not very effective)
oxymercuration - demercuration
hydroboration - oxidation
=>
Chapter 10 25
Glycols (Review)
Syn hydroxylation of alkenes
osmium tetroxide,hydrogen peroxide
cold,dilute,basic potassium
permanganate
Anti hydroxylation of alkenes
peroxyacids,hydrolysis
=>
Chapter 10 26
Organometallic
Reagents
Carbon is bonded to a metal (Mg or Li).
Carbon is nucleophilic (partially
negative).
It will attack a partially positive carbon.
C - X
C = O
A new carbon-carbon bond forms.
=>
Chapter 10 27
Grignard Reagents
Formula R-Mg-X (reacts like R:- +MgX)
Stabilized by anhydrous ether
Iodides most reactive
May be formed from any halide
primary
secondary
tertiary
vinyl
aryl =>
Chapter 10 28
Some Grignard
Reagents
B r
+ M g e t h e r
M g B r
C H 3 C H C H 2 C H 3
C l
e t h e r+ M g C H
3 C H C H 2 C H 3
M g C l
C H 3 C C H 2
B r + M g
e t h e r C H
3 C C H 2
M g B r
=>
Chapter 10 29
Organolithium Reagents
Formula R-Li (reacts like R:- +Li)
Can be produced from alkyl,vinyl,or
aryl halides,just like Grignard reagents.
Ether not necessary,wide variety of
solvents can be used.
=>
Chapter 10 30
Reaction with Carbonyl
R:- attacks the partially positive carbon in the
carbonyl.
The intermediate is an alkoxide ion.
Addition of water or dilute acid protonates the
alkoxide to produce an alcohol.
R C O
R C O
H O H
R C O H
OH=>
Chapter 10 31
Synthesis of 1°
Alcohols
Grignard + formaldehyde yields a primary
alcohol with one additional carbon.
C O
H
HC
C H 3
H 3 C C H 2 C M g B r
H
HH
C H 3 C H
C H 3
C H 2 C H 2 C
H
H
O M g B r
H O H
C H 3 C H
C H 3
C H 2 C H 2 C
H
H
O H
=>
Chapter 10 32
Synthesis of 2o Alcohols
Grignard + aldehyde yields a secondary
alcohol.
M g B rC H 3 C H
C H 3
C H 2 C H 2 C
C H 3
H
OC
C H 3
H 3 C C H 2 C M g B r
H
HH
C O
H
H 3 C
C H 3 C H
C H 3
C H 2 C H 2 C
C H 3
H
O H
H O H
=>
Chapter 10 33
Synthesis of 3o Alcohols
Grignard + ketone yields a tertiary alcohol.
M g B rC H 3 C H
C H 3
C H 2 C H 2 C
C H 3
C H 3
OC
C H 3
H 3 C C H 2 C M g B r
H
HH
C O
H 3 C
H 3 C
C H 3 C H
C H 3
C H 2 C H 2 C
C H 3
C H 3
O H
H O H
=>
Chapter 10 34
How would you
synthesize…
C H 3 C H 2 C H C H 2 C H 2 C H 3
O H C H
2 O H
O H
C H 3
C
O H
C H 2 C H 3
C H 3=>
Chapter 10 35
Grignard Reactions
with Acid Chlorides
and Esters
Use two moles of Grignard reagent.
The product is a tertiary alcohol with
two identical alkyl groups.
Reaction with one mole of Grignard
reagent produces a ketone
intermediate,which reacts with the
second mole of Grignard reagent.
=>
Chapter 10 36
Grignard + Acid
Chloride (1)
C O
C l
H 3 C
M g B rR M g B r C
C H 3
C l
OR
C
C H 3
C l
OR M g B r C
C H 3
R
O
+ M g B r C l
Ketone intermediate =>
Grignard attacks the carbonyl.
Chloride ion leaves.
Chapter 10 37
Grignard and Ester (1)
Grignard attacks the carbonyl.
Alkoxide ion leaves!? !
C O
C H 3 O
H 3 C
M g B rR M g B r C
C H 3
O C H 3
OR
C
C H 3
O C H 3
OR M g B r C
C H 3
R
O
+ M g B r O C H 3
Ketone intermediate =>
Chapter 10 38
Second step of reaction
Second mole of Grignard reacts with the
ketone intermediate to form an alkoxide ion.
Alkoxide ion is protonated with dilute acid.
C
C H 3
R
O
R M g B r + C
C H 3
R
OR M g B rH O H
C
C H 3
R
O HR
=>
Chapter 10 39
How would you
synthesize...
C H 3 C H 2 C C H 3
O H
C H 3
C
O H
C H 3
Using an acid chloride or ester.
C H 3 C H 2 C H C H 2 C H 3
O H =>
Chapter 10 40
Grignard Reagent +
Ethylene Oxide
Epoxides are unusually reactive ethers.
Product is a 1o alcohol with 2 additional
carbons.
M g B r + C H 2 C H 2
O
C H 2 C H 2
O M g B r
H O H
C H 2 C H 2
O H
=>
Chapter 10 41
Limitations of Grignard
No water or other acidic protons like
O-H,N-H,S-H,or -C—C-H,Grignard
reagent is destroyed,becomes an
alkane.
No other electrophilic multiple bonds,
like C=N,C—N,S=O,or N=O.
=>
Chapter 10 42
Reduction of Carbonyl
Reduction of aldehyde yields 1o alcohol.
Reduction of ketone yields 2o alcohol.
Reagents:
Sodium borohydride,NaBH4
Lithium aluminum hydride,LiAlH4
Raney nickel
=>
Chapter 10 43
Sodium Borohydride
Hydride ion,H-,attacks the carbonyl
carbon,forming an alkoxide ion.
Then the alkoxide ion is protonated by
dilute acid.
Only reacts with carbonyl of aldehyde or
ketone,not with carbonyls of esters or
carboxylic acids.
H
C
O
H
C
H
OH
C
H
OH H
H 3 O +
=>
Chapter 10 44
Lithium Aluminum
Hydride
Stronger reducing agent than sodium
borohydride,but dangerous to work with.
Converts esters and acids to 1o alcohols.
C
O
O C H 3 C
OH H
H
H 3 O +L A H=>
Chapter 10 45
Comparison of
Reducing Agents
LiAlH4 is stronger.
LiAlH4 reduces more
stable compounds
which are resistant
to reduction.
=>
Chapter 10 46
Catalytic Hydrogenation
Add H2 with Raney nickel catalyst.
Also reduces any C=C bonds.
O
H 2,R a n e y N i
O H
N a B H 4
O H
=>
Chapter 10 47
Thiols (Mercaptans)
Sulfur analogues of alcohols,-SH.
Named by adding -thiol to alkane name.
The -SH group is called mercapto.
Complex with heavy metals,Hg,As,Au.
More acidic than alcohols,react with
NaOH to form thiolate ion.
Stinks! =>
Chapter 10 48
Thiol Synthesis
Use a large excess of sodium
hydrosulfide with unhindered alkyl
halide to prevent dialkylation to R-S-R.
H S
_
R X R S H +
_
X
=>
Chapter 10 49
Thiol Oxidation
Easily oxidized to disulfides,an
important feature of protein structure.
R S H + RH S
B r 2
Z n,H C l
R S S R + 2 H B r
Vigorous oxidation with KMnO4,
HNO3,or NaOCl,produces sulfonic acids.
S H
H N O 3
b o i l
S
O
O
O H
=>
Chapter 10 50
End of Chapter 10
Structure and Synthesis
of Alcohols
Jo Blackburn
Richland College,Dallas,TX
Dallas County Community College District
2003,Prentice Hall
Organic Chemistry,5th Edition
L,G,Wade,Jr.
Chapter 10 2
Structure of Alcohols
Hydroxyl (OH) functional group
Oxygen is sp3 hybridized,
=>
Chapter 10 3
Classification
Primary,carbon with –OH is bonded to
one other carbon.
Secondary,carbon with –OH is bonded
to two other carbons.
Tertiary,carbon with –OH is bonded to
three other carbons.
Aromatic (phenol),-OH is bonded to a
benzene ring.
=>
Chapter 10 4
Classify these:
C H 3 C H
C H 3
C H 2 O H C H 3 C
C H 3
C H 3
O H
O H
C H 3 C H
O H
C H 2 C H 3=>
Chapter 10 5
IUPAC Nomenclature
Find the longest carbon chain
containing the carbon with the -OH
group.
Drop the -e from the alkane name,add -
ol.
Number the chain,starting from the end
closest to the -OH group.
Number and name all substituents,=>
Chapter 10 6
Name these:
C H 3 C H
C H 3
C H 2 O H
C H 3 C
C H 3
C H 3
O H
C H 3 C H
O H
C H 2 C H 32-methyl-1-propanol
2-methyl-2-propanol
2-butanol
O H
B r C H
3
3-bromo-3-methylcyclohexanol
=>
Chapter 10 7
Unsaturated Alcohols
Hydroxyl group takes precedence,Assign
that carbon the lowest number.
Use alkene or alkyne name.
4-penten-2-ol (old)
pent-4-ene-2-ol
(1997 revision of IUPAC rules)
=>
C H 2 C H C H 2 C H C H 3
O H
Chapter 10 8
Naming Priority
Acids
Esters
Aldehydes
Ketones
Alcohols
Amines
Alkenes
Alkynes
Alkanes
Ethers
Halides
=>
Chapter 10 9
Hydroxy Substituent
When -OH is part of a higher priority class of
compound,it is named as hydroxy.
Example:
C H 2 C H 2 C H 2 C O O H
O H
4-hydroxybutanoic acid
also known as GHB
=>
Chapter 10 10
Common Names
Alcohol can be named as alkyl alcohol.
Useful only for small alkyl groups.
Examples:
C H 3 C H
C H 3
C H 2 O H C H
3 C H
O H
C H 2 C H 3
isobutyl alcohol sec-butyl alcohol
=>
Chapter 10 11
Naming Diols
Two numbers are needed to locate the two
-OH groups.
Use -diol as suffix instead of -ol.
H O O H
1,6-hexanediol
=>
Chapter 10 12
Glycols
1,2 diols (vicinal diols) are called glycols.
Common names for glycols use the name of
the alkene from which they were made.
C H 2 C H 2
O H O H
C H 2 C H 2 C H 3
O H O H
1,2-ethanediol
ethylene glycol
1,2-propanediol
propylene glycol
=>
Chapter 10 13
Naming Phenols
-OH group is assumed to be on carbon 1.
For common names of disubstituted phenols,
use ortho- for 1,2; meta- for 1,3; and para- for
1,4.
Methyl phenols are cresols.
O H
C l
3-chlorophenol
meta-chlorophenol
O H
H 3 C
4-methylphenol
para-cresol
=>
Chapter 10 14
Physical Properties
Unusually high boiling points due to
hydrogen bonding between molecules.
Small alcohols are miscible in water,but
solubility decreases as the size of the
alkyl group increases.
=>
Chapter 10 15
Boiling Points
=>
Chapter 10 16
Solubility in Water
Solubility decreases as the size
of the alkyl group increases.
=>
Chapter 10 17
Methanol
―Wood alcohol‖
Industrial production from synthesis gas
Common industrial solvent
Fuel at Indianapolis 500
Fire can be extinguished with water
High octane rating
Low emissions
But,lower energy content
Invisible flame =>
Chapter 10 18
Ethanol
Fermentation of sugar and starches in grains
12-15% alcohol,then yeast cells die.
Distillation produces ―hard‖ liquors
Azeotrope,95% ethanol,constant boiling
Denatured alcohol used as solvent
Gasahol,10% ethanol in gasoline
Toxic dose,200 mL ethanol,100 mL methanol
=>
Chapter 10 19
2-Propanol
―Rubbing alcohol‖
Catalytic hydration of propene
=>
C H 2 C H C H 2 H 2 O 1 0 0 - 3 0 0 a t m,3 0 0 癈c a t a l y s t+ C H 3 C H
O H
C H 3
Chapter 10 20
Acidity of Alcohols
pKa range,15.5-18.0 (water,15.7)
Acidity decreases as alkyl group
increases.
Halogens increase the acidity.
Phenol is 100 million times more acidic
than cyclohexanol!
=>
Chapter 10 21
Table of Ka Values
=>
CH3 OH
Chapter 10 22
Formation of Alkoxide
Ions
React methanol and ethanol with sodium
metal (redox reaction).
C H 3 C H 2 O H + N a C H 3 C H 2 O N a + 1 / 2 H 2
React less acidic alcohols with more
reactive potassium,
+ K ( C H 3 ) 3 C O K + 1 / 2 H 2) 3 C O H( C H 3
=>
Chapter 10 23
Formation of Phenoxide
Ion
Phenol reacts with hydroxide ions to form
phenoxide ions - no redox is necessary.
O H
+ OH
O
+ HOH
pKa = 10 pKa = 15.7
=>
Chapter 10 24
Synthesis (Review)
Nucleophilic substitution of OH- on alkyl
halide
Hydration of alkenes
water in acid solution (not very effective)
oxymercuration - demercuration
hydroboration - oxidation
=>
Chapter 10 25
Glycols (Review)
Syn hydroxylation of alkenes
osmium tetroxide,hydrogen peroxide
cold,dilute,basic potassium
permanganate
Anti hydroxylation of alkenes
peroxyacids,hydrolysis
=>
Chapter 10 26
Organometallic
Reagents
Carbon is bonded to a metal (Mg or Li).
Carbon is nucleophilic (partially
negative).
It will attack a partially positive carbon.
C - X
C = O
A new carbon-carbon bond forms.
=>
Chapter 10 27
Grignard Reagents
Formula R-Mg-X (reacts like R:- +MgX)
Stabilized by anhydrous ether
Iodides most reactive
May be formed from any halide
primary
secondary
tertiary
vinyl
aryl =>
Chapter 10 28
Some Grignard
Reagents
B r
+ M g e t h e r
M g B r
C H 3 C H C H 2 C H 3
C l
e t h e r+ M g C H
3 C H C H 2 C H 3
M g C l
C H 3 C C H 2
B r + M g
e t h e r C H
3 C C H 2
M g B r
=>
Chapter 10 29
Organolithium Reagents
Formula R-Li (reacts like R:- +Li)
Can be produced from alkyl,vinyl,or
aryl halides,just like Grignard reagents.
Ether not necessary,wide variety of
solvents can be used.
=>
Chapter 10 30
Reaction with Carbonyl
R:- attacks the partially positive carbon in the
carbonyl.
The intermediate is an alkoxide ion.
Addition of water or dilute acid protonates the
alkoxide to produce an alcohol.
R C O
R C O
H O H
R C O H
OH=>
Chapter 10 31
Synthesis of 1°
Alcohols
Grignard + formaldehyde yields a primary
alcohol with one additional carbon.
C O
H
HC
C H 3
H 3 C C H 2 C M g B r
H
HH
C H 3 C H
C H 3
C H 2 C H 2 C
H
H
O M g B r
H O H
C H 3 C H
C H 3
C H 2 C H 2 C
H
H
O H
=>
Chapter 10 32
Synthesis of 2o Alcohols
Grignard + aldehyde yields a secondary
alcohol.
M g B rC H 3 C H
C H 3
C H 2 C H 2 C
C H 3
H
OC
C H 3
H 3 C C H 2 C M g B r
H
HH
C O
H
H 3 C
C H 3 C H
C H 3
C H 2 C H 2 C
C H 3
H
O H
H O H
=>
Chapter 10 33
Synthesis of 3o Alcohols
Grignard + ketone yields a tertiary alcohol.
M g B rC H 3 C H
C H 3
C H 2 C H 2 C
C H 3
C H 3
OC
C H 3
H 3 C C H 2 C M g B r
H
HH
C O
H 3 C
H 3 C
C H 3 C H
C H 3
C H 2 C H 2 C
C H 3
C H 3
O H
H O H
=>
Chapter 10 34
How would you
synthesize…
C H 3 C H 2 C H C H 2 C H 2 C H 3
O H C H
2 O H
O H
C H 3
C
O H
C H 2 C H 3
C H 3=>
Chapter 10 35
Grignard Reactions
with Acid Chlorides
and Esters
Use two moles of Grignard reagent.
The product is a tertiary alcohol with
two identical alkyl groups.
Reaction with one mole of Grignard
reagent produces a ketone
intermediate,which reacts with the
second mole of Grignard reagent.
=>
Chapter 10 36
Grignard + Acid
Chloride (1)
C O
C l
H 3 C
M g B rR M g B r C
C H 3
C l
OR
C
C H 3
C l
OR M g B r C
C H 3
R
O
+ M g B r C l
Ketone intermediate =>
Grignard attacks the carbonyl.
Chloride ion leaves.
Chapter 10 37
Grignard and Ester (1)
Grignard attacks the carbonyl.
Alkoxide ion leaves!? !
C O
C H 3 O
H 3 C
M g B rR M g B r C
C H 3
O C H 3
OR
C
C H 3
O C H 3
OR M g B r C
C H 3
R
O
+ M g B r O C H 3
Ketone intermediate =>
Chapter 10 38
Second step of reaction
Second mole of Grignard reacts with the
ketone intermediate to form an alkoxide ion.
Alkoxide ion is protonated with dilute acid.
C
C H 3
R
O
R M g B r + C
C H 3
R
OR M g B rH O H
C
C H 3
R
O HR
=>
Chapter 10 39
How would you
synthesize...
C H 3 C H 2 C C H 3
O H
C H 3
C
O H
C H 3
Using an acid chloride or ester.
C H 3 C H 2 C H C H 2 C H 3
O H =>
Chapter 10 40
Grignard Reagent +
Ethylene Oxide
Epoxides are unusually reactive ethers.
Product is a 1o alcohol with 2 additional
carbons.
M g B r + C H 2 C H 2
O
C H 2 C H 2
O M g B r
H O H
C H 2 C H 2
O H
=>
Chapter 10 41
Limitations of Grignard
No water or other acidic protons like
O-H,N-H,S-H,or -C—C-H,Grignard
reagent is destroyed,becomes an
alkane.
No other electrophilic multiple bonds,
like C=N,C—N,S=O,or N=O.
=>
Chapter 10 42
Reduction of Carbonyl
Reduction of aldehyde yields 1o alcohol.
Reduction of ketone yields 2o alcohol.
Reagents:
Sodium borohydride,NaBH4
Lithium aluminum hydride,LiAlH4
Raney nickel
=>
Chapter 10 43
Sodium Borohydride
Hydride ion,H-,attacks the carbonyl
carbon,forming an alkoxide ion.
Then the alkoxide ion is protonated by
dilute acid.
Only reacts with carbonyl of aldehyde or
ketone,not with carbonyls of esters or
carboxylic acids.
H
C
O
H
C
H
OH
C
H
OH H
H 3 O +
=>
Chapter 10 44
Lithium Aluminum
Hydride
Stronger reducing agent than sodium
borohydride,but dangerous to work with.
Converts esters and acids to 1o alcohols.
C
O
O C H 3 C
OH H
H
H 3 O +L A H=>
Chapter 10 45
Comparison of
Reducing Agents
LiAlH4 is stronger.
LiAlH4 reduces more
stable compounds
which are resistant
to reduction.
=>
Chapter 10 46
Catalytic Hydrogenation
Add H2 with Raney nickel catalyst.
Also reduces any C=C bonds.
O
H 2,R a n e y N i
O H
N a B H 4
O H
=>
Chapter 10 47
Thiols (Mercaptans)
Sulfur analogues of alcohols,-SH.
Named by adding -thiol to alkane name.
The -SH group is called mercapto.
Complex with heavy metals,Hg,As,Au.
More acidic than alcohols,react with
NaOH to form thiolate ion.
Stinks! =>
Chapter 10 48
Thiol Synthesis
Use a large excess of sodium
hydrosulfide with unhindered alkyl
halide to prevent dialkylation to R-S-R.
H S
_
R X R S H +
_
X
=>
Chapter 10 49
Thiol Oxidation
Easily oxidized to disulfides,an
important feature of protein structure.
R S H + RH S
B r 2
Z n,H C l
R S S R + 2 H B r
Vigorous oxidation with KMnO4,
HNO3,or NaOCl,produces sulfonic acids.
S H
H N O 3
b o i l
S
O
O
O H
=>
Chapter 10 50
End of Chapter 10
