Alcohols and Phenols

1
Chapter 17
Alcohols and Phenols
2
Introduction

• Alcohols are compounds with a OH group bonded to
  a saturated C (sp3-hybridized)
• Phenols are compounds with a OH group bonded to
  a carbon in a benzene ring

3

• Alcohols are abundant in nature they are
  important solvents and synthesis intermediates
• Methanol, CH3OH, called methyl alcohol, is a
  common solvent, a starting material and a fuel
  additive it is produced in large quantities by
  catalytic reduction

4

• Ethanol, CH3CH2OH, called ethyl alcohol, is a
  solvent, fuel, beverage it is produced in large
  quantities by acid-catalyzed hydration of ethylene

5

• Phenol, C6H5OH (phenyl alcohol) is abundant in
  nature it has diverse uses
• It gives its name to the general class of
  compounds

flavoring agent (oil of wintergreen)
allergens (poison oak or ivy )
6
1. Naming Alcohols and Phenols

• Alcohols are classified as primary (1),
  secondary (2), or tertiary (3) based on
  substitution on C to which OH is attached
• Primary (1) (C has two Hs, one R)
• Secondary (2) (C has one H, two Rs)
• Tertiary (3) (C has no H, 3 Rs)

7
Naming Alcohols

• Alcohols are named according to the IUPAC system
• Select the longest carbon chain containing the OH
  group, and derive the parent name by replacing
  the -e ending of the corresponding alkane with
  -ol
• Number the chain from the end nearer the OH group
• Number substituents according to position on
  chain, listing the substituents in alphabetical
  order

8
(No Transcript)
9

• Many alcohols have common names, accepted by
  IUPAC

10
Naming Phenols

• Phenols are named according to the IUPAC system
• Use phene (the French name for benzene) as the
  parent hydrocarbon name, not benzene, followed by
  the suffix ol to indicate the OH substituent
• Number substituents on aromatic ring by their
  position from OH

11
Practice Problem Give IUPAC names for the
following compounds
12
Practice Problem Draw structures corresponding
to the following IUPAC names

• 2-Ethyl-2-buten-1-ol
• 3-Cyclohexen-1-ol
• trans-3-Chlorocycloheptanol
• 1,4-Pentanediol
• 2,6-Dimethylphenol
• o-(2-Hydroxyethyl)phenol

13
2. Properties of Alcohols and Phenols
Hydrogen Bonding

• The geometry around the O atom of an alcohol
  (ROH) and phenol (ArOH) is similar to that of
  water (HOH)
• The C-O-H bond angle has the tetrahedral value
• The O atom is sp3-hybridized

14

• Alcohols and phenols have much higher boiling
  points than alkanes and alkyl halides with
  similar MW

15

• Alcohols and phenols have high boiling points
  because they form hydrogen bonds (like H2O) in
  solution
• A hydrogen bond is a weak attraction between a H
  bonded to an electronegative atom and an electron
  lone pair on another electronegative atom
• This intermolecular force elevates the boiling
  point

16

• The attraction of a d H atom of OH from one
  molecule to a lone pair of electrons on a d- O
  atom of another molecule produces a force that
  holds the two molecules together
• This intermolecular attraction (present in
  solution but not in the gas phase) must be
  overcome for the molecules to enter the gas
  phase, thus elevating the boiling point of the
  solution

17
Practice Problem The following data for isomeric
four-carbon alcohols show that there is
a decrease in boiling point with
increasing substitution. How might you
account for this trend?
1-Butanol, bp 117.5oC 2-Butanol, bp
99.5oC 2-Methyl-2-propanol, bp 82.2oC
18
3. Properties of Alcohols and Phenols
Acidity and Basicity

• Alcohols and phenols are both weakly basic and
  weakly acidic
• They act as Brønsted bases in the presence of a
  strong acid
• They act as Brønsted acids in the presence of a
  strong base

19

• Alcohols and phenols are weak Brønsted bases
• They are protonated by strong acids to yield
  oxonium ions, ROH2

20

• Alcohols and phenols are weak Brønsted acids
• They can transfer a proton to water to a very
  small extent
• They produce H3O and an alkoxide ion, RO?, or a
  phenoxide ion, ArO?

21
Brønsted Acidity Measurements

• The acidity constant, Ka, measures the extent to
  which a Brønsted acid transfers a proton to water

?
?
HA H2O A? H3O
A? H3O
Ka Keq H2O
HA

• A larger value of Ka indicates a stronger acid

22
pKa The acid strength scale

• Acid strength is expressed using pKa values
• pKa - log Ka

• The free energy in an equilibrium is related to
  -ln of Keq
• DG -RT ln Keq

• Relative acidities are more conveniently
  presented on a logarithmic scale, pKa, which is
  directly proportional to the free energy of the
  equilibrium

23

• Differences in pKa correspond to differences in
  free energy

DpKa log Keq2/Keq1

• DpKa can be used to calculate the extent of H
  transfer

24

• H will always go from the stronger acid to the
  stronger base
• The stronger the acid, the weaker its conjugate
  base. The weaker the acid, the stronger the
  conjugate base.

25
The larger the Ka, the smaller the pKa, the
stronger the acid
26
Alcohol Acidity

• Simple alcohols are about as acidic as water
• pKa H2O 15.74
• pKa CH3OH 15.54
• pKa CH3CH2OH 16.00
• Factors that affect alcohol acidity include
• Alkyl Substitution (Steric Effects)
• Inductive Effects

27

• Effect of Alkyl Substitution
• Higher alkyl groups decrease the acidity of an
  alcohol due to decreased solvation of the
  alkoxide ion
• The less easily the alkoxide ion is solvated by
  water, the less stable, the less its formation is
  energetically favored, the lower the acidity
• Steric hindrance on alkoxide ion decreases
  solvation

28

• Steric hindrance on alkoxide ion decreases
  solvation
• CH3OH has an unhindered O on the methoxide ion,
  CH3O-
• (CH3)3OH has a hindered O on the t-butoxide ion,
  (CH3)3O-

29

• Inductive Effects
• Electron-withdrawing groups make an alcohol a
  stronger acid by stabilizing the conjugate base
  (alkoxide)

Nonafluoro-t-butoxide ion t-butoxide
ion
30
Alcohols generate alkoxides

• Alcohols are weak acids. They require a strong
  base
• They form alkoxides upon reaction with
• alkali metals,
• sodium hydride (NaH),
• sodium amide (NaNH2), and
• Grignard reagents (RMgX)
• Alkoxides are used as basic reagents in organic
  chemistry

31
Alcohols form alkoxides upon reaction with
alkali metals, NaH, NaNH2, and Grignard reagents
(RMgX)
32
Phenol Acidity

• Phenols (pKa 10) are much more acidic than
  alcohols (pKa 16) due to resonance
  stabilization of the phenoxide ion

33

• The resonance-stabilized phenoxide anion is more
  stable than the methoxide anion. The negative
  charge in phenoxide is delocalized (spread over)
  from O to the ring.

34

• Phenols react with NaOH solutions (but alcohols
  do not), forming salts that are soluble in dilute
  aqueous solutions
• A phenolic component can be separated from an
  organic solution by extraction into basic
  aqueous solution followed by addition of acid
  into the solution

35
Effect of Substitution on phenol acidity

• Substituted phenols can be more or less acidic
  than phenol itself
• An electron-withdrawing substituent makes a
  phenol more acidic because it delocalizes the
  negative charge
• An electron-donating substituent makes a phenol
  less acidic because it concentrates the charge

36

• Nitro phenols
• Phenols with nitro groups at the ortho and para
  positions are much stronger acids
• The pKa of 2,4,6-trinitrophenol is 0.6, a very
  strong acid

37
Practice Problem Is p-cyanophenol more acidic or
less acidic than phenol?
C?N, an electron-withdrawing group, increases
the acidity of phenol by stabilizing the negative
charge on the phenoxide ion.
38
Practice Problem Rank the following substances
in order of increasing acidity

• (CH3)2CHOH, HC?CH, (CF3)2CHOH, CH3OH
• Phenol, p-methylphenol, p-(trifluoromethyl)phenol
• Benzyl alcohol, phenol, p-hydroxybenzoic acid

39
Practice Problem p-Nitrobenzyl alcohol is more
acidic than benzyl alcohol but
p-methoxybenzyl alcohol is less acidic.
Explain
40
4. Preparation of Alcohols A Review

• Alcohols are very useful in synthesis because
• They can be derived from many types of compounds
• They can be converted to many other types of
  compounds (with different functional groups)

41
(No Transcript)
42
Preparation of Alcohols by Regiospecific
Hydration of Alkenes

• Hydroboration/oxidation syn, non-Markovnikov
  hydration
• Oxymercuration/reduction Markovnikov hydration

43
Preparation of 1,2-Diols

• Cis-1,2-diols Hydroxylation of an alkene with
  OsO4 followed by reduction with NaHSO3
• Trans-1,2-diols Acid-catalyzed hydrolysis of
  epoxides

44

• There is a new nomenclature for cis and trans
  diols
• Select a reference substituent r (with lowest
  sequence number or with higher Cahn-Ingold-Prelog
  priority)
• Assign the other either cis (c) or trans (t) to
  the reference

1-methyl-r1,c2-cyclo- -hexanediol
1-methyl-r1,t2-cyclo- -hexanediol
45
Practice Problem Predict the products of the
following reactions
(c) cis-5-decene

• OsO4
• NaHSO3

?
46
5. Alcohols from Reduction of Carbonyl
Compounds

• Reduction of a carbonyl compound in general gives
  an alcohol
• Note that organic reduction reactions add the
  equivalent of H2 to a molecule

47
Reduction of Aldehydes and Ketones

• Aldehydes are reduced to give primary alcohols
• Ketones are reduced to give secondary alcohols

48
Reduction Reagent Sodium Borohydride (NaBH4)

• NaBH4 is not sensitive to moisture and it does
  not reduce other common functional groups
• It adds the equivalent of H-

49
Reduction Reagent Lithium Aluminum Hydride
(LiAlH4)

• LiAlH4 is more powerful, less specific, and very
  reactive with water
• Like NaBH4, it adds the equivalent of H-

50
Reduction of Carboxylic Acids and Esters

• Carboxylic acids and esters are reduced to give
  primary alcohols
• LiAlH4 is used because NaBH4 is not effective for
  carboxylic acids and esters

51
Reduction Reagent Lithium Aluminum Hydride
(LiAlH4)

• LiAlH4 is used because NaBH4 is not effective
• It adds the equivalent of two H-

52
Mechanism of Reduction

• The mechanism involves
• Addition of nucleophilic hydride ion, H-, to the
  positively polarized electrophilic carbon of CO
  to form an alkoxide ion intermediate
• Protonation of the alkoxide ion intermediate

53
Practice Problem What carbonyl compounds would
you reduce to obtain the following
alcohols?
54
Practice Problem What reagent would you use to
accomplish each of the following
reactions?
55
Practice Problem What carbonyl compounds give
the following alcohols on reduction
with LiAlH4? Show all possibilities
56
6. Alcohols from Reaction of Carbonyl
Compounds with Grignard Reagents

• Alkyl, aryl, and vinylic halides react with Mg in
  ether or THF to generate Grignard reagents, RMgX
• Grignard reagents react with carbonyl compounds
  to yield alcohols

57
Grignard addition to carbonyl compounds

• Formaldehydes react with Grignard reagents to
  give primary alcohols

Formaldehyde
58

• Aldehydes react with Grignard reagents to give
  secondary alcohols

59

• Ketones react with Grignard reagents to give
  tertiary alcohols

60
Examples of Reactions of Grignard Reagents with
Carbonyl Compounds
61

• Esters react with Grignard reagents to give
  tertiary alcohols in which two of the
  substituents R on OH-bearing carbon come from the
  Grignard reagent

62

• Grignard reagents do not add to carboxylic acids
• They undergo an acid-base reaction, generating
  the hydrocarbon of the Grignard reagent and the
  carboxylic acid salt

Base Acid ? Hydrocarbon
Salt
63
Limitations of the Grignard Reaction

• Grignard reagents can't be prepared from
  alkylhalides if there are reactive functional
  groups, FG, in the same molecule, including
  proton donors

64
Mechanism of the Addition of a Grignard Reagent

• There are two steps
• Grignard reagents act as nucleophilic carbon
  anions (carbanions, R?) in adding to a
  carbonyl group
• The intermediate alkoxide is then protonated to
  produce the alcohol

65
Practice Problem How would you use the addition
of a Grignard reagent to a ketone to
synthesize 2-phenyl-2- propanol?
66
Practice Problem How would you use the reaction
of a Grignard reagent with a carbonyl
compound to synthesize
2-methyl-2-pentanol?
OR
67
Practice Problem Show the products obtained from
addition of methylmagnesium bromide to
the following compounds

• Cyclopentanone
• Benzophenone (diphenyl ketone)
• 3-Hexanone

68
Practice Problem Use a Grignard reaction to
prepare the following alcohols

• 2-Methyl-2-propanol
• 1-Methylcyclohexanol
• 3-Methyl-3-pentanol
• 2-Phenyl-2-butanol
• Benzyl alcohol

69
Practice Problem Use the reaction of a Grignard
reagent with a carbonyl compound to
synthesize the following compound
70
7. Some Reactions of Alcohols

• There are two general classes of alcohol
  reactions
• At the carbon of the CO bond
• At the proton of the OH bond

71
Dehydration of Alcohols to Yield Alkenes

• Dehydration of alcohol involves loss of O-H and H
  of the neighboring CH to give a ? bond (an
  alkene)
• Specific reagents are needed
• Acid catalysts (H3O)
• Phosphorus oxychloride in pyridine
  (POCl3/pyridine)

72
Acid-Catalyzed Dehydration

• Acid-catalyzed dehydration usually follows
  Zaitsevs rule
• It produces the more stable (more highly
  substituted) alkene

73

• It is an E1 process with a three-step mechanism
• protonation of the alcohol O
• spontaneous loss of H2O to yield a carbocation
  intermediate
• loss of proton H from the neighboring carbon

74

• The reactivity order for acid-catalyzed
  dehydration is
• Tertiary alcohols are readily dehydrated with
  acid
• Secondary alcohols require severe conditions (75
  H2SO4, 100C) - Sensitive molecules don't survive
• Primary alcohols require very harsh conditions
  Impractical

75

• The reactivity order is the result of the
  stability of the carbocation intermediate

Primary lt Secondary lt Tertiary Carbocation Carboc
ation Carbocation
76
Dehydration with POCl3

• Phosphorus oxychloride POCl3 in the amine solvent
  pyridine can lead to dehydration of secondary 2o
  and tertiary 3o alcohols at low temperatures

77

• It is an E2 process via an intermediate ester of
  POCl2
• reaction of the alcohol O with POCl3 to form a
  dichlorophosphate intermediate
• abstraction of H by pyridine and loss of OPOCl2

78
Practice Problem What product(s) would you
expect from dehydration of the
following alcohols with POCl3 in
pyridine? Indicate the major product in
each case.
79
Conversion of Alcohols into Alkyl Halides

• 3 alcohols are converted into alkyl halides by
  HCl or HBr at low temperature
• 1 and 2o alcohols are resistant to acid They
  are converted into alkyl halides by SOCl2 or PBr3

SN1
SN2
80

• The reaction of 3o alcohol with HX occurs by an
  SN1 mechanism
• protonation of the alcohol O
• spontaneous loss of H2O to yield a carbocation
  intermediate
• Attack by nucleophilic halide ion on the
  carbocation

81

• The reactions of 1o and 2o alcohols with SOCl2 or
  PBr3 occur by SN2 mechanisms
• Reaction of SOCl2 or PBr3 converts the OH into
  OSOCl or OPBr2 (better leaving groups than OH)
• Backside nucleophilic substitution of Cl- or Br-
  expels OSOCl or OPBr2

82
Conversion of Alcohols into Tosylates

• Alcohols react with p-toluenesulfonyl chloride
  (tosyl chloride, p-TosCl) in pyridine to yield
  alkyl tosylates, ROTos
• Formation of the tosylate does not involve the
  CO bond so configuration at a chirality center
  is maintained
• Alkyl tosylates behave like alkyl halides (SN1
  and SN2 reaction)

83

• Stereochemical Uses of Tosylates
• The SN2 reaction of an alcohol via an alkyl
  halide proceeds with two inversions, giving
  product with same absolute stereochemistry as
  starting alcohol
• The SN2 reaction of an alcohol via a tosylate,
  produces one inversion at the chirality center,
  giving product with opposite absolute
  stereochemistry to starting alcohol

84
Practice Problem How would you carry out the
following transformation, a step used
in the synthesis of (S)-ibuprofen?
85
8. Oxidation of Alcohols

• Alcohols undergo oxidation reactions to yield
  carbonyl compounds

86

• Primary alcohols yield aldehydes or carboxylic
  acids
• Secondary alcohols yield ketones
• Tertiary alcohols do not react with oxidizing
  agents

87

• The oxidation of primary and secondary alcohols
  can be accomplished by inorganic reagents, such
  as KMnO4, CrO3, and Na2Cr2O7 or by more
  selective, expensive reagents

88
Oxidation of Primary Alcohols

• Primary alcohols are converted to
• aldehydes via pyridinium chlorochromate (PCC,
  C5H6NCrO3Cl) in dichloromethane
• carboxylic acids via other reagents (CrO3, )

89
Oxidation of Secondary Alcohols

• Secondary alcohols are converted to ketones
• This is effective with inexpensive reagents such
  as Na2Cr2O7 in acetic acid
• PCC is used for sensitive alcohols at lower
  temperatures

90
Mechanism of Chromic Acid Oxidation

• It is an E2-like mechanistic pathway
• Alcohol reacts with Cr(VI) to form a chromate
  ester followed by elimination of Hs and
  expulsion of Cr (the leaving group) to give
  carbonyl product
• The mechanism was determined by observing the
  effects of isotopes on rates

91
Practice Problem What alcohols would give the
following products on oxidation?
92
Practice Problem What products would you expect
from oxidation of the following
compounds with CrO3 in aqueous acid?
With pyridinium chlorochromate?

• 1-Hexanol
• 2-Hexanol
• Hexanal

93
9. Protection of Alcohols

• Hydroxyl groups can easily transfer their proton
  to a basic reagent
• This can prevent desired reactions
• Converting the hydroxyl to a (removable)
  functional group without an acidic proton
  protects the alcohol

94

• When one functional group in a molecule
  interferes with an intended reaction, it is
  possible to avoid the problem by protecting the
  interfering functional group by
• introducing a protecting group to block the
  interfering function
• carrying out the desired reaction
• removing the protecting group

95
Common Method to Protect Alcohols

• Reaction with chlorotrimethylsilane in the
  presence of base yields an unreactive
  trimethylsilyl (TMS) ether
• The base (usually triethylamine) helps to form
  the alkoxide anion and to remove the HCl
  by-product

96

• The ether can be cleaved with acid or with
  fluoride ion to regenerate the alcohol
• The ether has no acidic Hs and is protected from
  oxidizing agents, reducing agents, and Grignard
  reagents

97
Protection-Deprotection An Example

• Use of TMS-alcohol protection during Grignard
  reaction of 3-bromo-1-propanol to acetaldehyde

98

• A nucleophile reacts with Si of TMS via SN2 even
  though Si is a 3o center
• Si is less hindered. It is larger than C and
  forms longer bonds

99
Practice Problem TMS ethers can be removed by
treatment with fluoride ion as well as
by acid-catalyzed hydrolysis. Propose
a mechanism for the reaction of
cyclohexyl TMS ether with LiF.
Fluorotrimethylsilane is a product.
100
10. Preparation and Uses of Phenols

• Phenols can be prepared by
• reaction of chlorobenzene with NaOH at high
  temperature and pressure
• reaction of cumene (isopropylbenzene) with O2,
  followed by treatment with acid
• alkali fusion of aryl sulfonate

101

• Phenol is prepared on an industrial scale by
  treatment of chlorobenzene with dilute aqueous
  NaOH at 340C under high pressure

102

• Another industrial process of phenol synthesis
  involves readily available cumene and O2/H3O
• It forms cumene hydroperoxide with O2 at high
  temperature
• It is converted into phenol and acetone by acid
  (H3O)

103

• Cumene hydroperoxide is acid-catalyzed to form
  phenol
• protonation of O
• rearrangement of the phenyl group from C to O
  with simultaneous loss of H2O
• readdition of H2O then yields a hemiacetal
  intermediate, which breaks down to phenol and
  acetone

104

• A laboratory preparation of phenols involves
  melting aromatic sulfonic acids with NaOH at high
  temperature
• It is limited to the preparation of
  alkyl-substituted phenols

105

• Phenol is the starting material for synthesis of
• chlorinated phenols (eg. pentachlorophenol,
  2,4-D, hexachlorphene,)

106

• Phenol is the starting material for synthesis of
• food preservatives BHT (butylated hydroxytoluene)
  and BHA (butylated hydroxyanisole)

107
Practice Problem p-Cresol (p-methylphenol) is
used both as an antiseptic and as a
starting material to prepare the food
additive BHT. How would you prepare
p-cresol from benzene?
108
Practice Problem Show the mechanism of the
reaction of p- methylphenol with
2-methylpropene and H3PO4 catalyst to
yield the food additive BHT
109
11. Reactions of Phenols

• Phenols can undergo
• Electrophilic Aromatic Substitution Reactions
• Oxidations

110
Electrophilic Aromatic Substitution Reactions

• The hydroxyl group is strongly activating, ortho-
  and para-directing
• Phenols are highly reactive substrates for
  electrophilic aromatic reactions
• halogenation,
• nitration,
• sulfonation, and
• FriedelCrafts reactions

111
Oxidation of Phenols Quinones

• Reaction of a phenol with strong oxidizing agents
  yields a quinone (or 2,5-cyclohexadiene-1,4-dione)
  
• Fremy's salt (KSO3)2NO, potassium
  nitrosodisulfonate works under mild conditions
  through a radical mechanism

112
Oxidation-reduction of quinones

• Quinones can be easily reduced to hydroquinones
  (p-dihydroxybenzenes) by NaBH4 or SnCl2
• Hydroquinones can be easily reoxidized to
  quinones by Fremy's salt

113
Quinones in nature

• Ubiquinones, also called coenzymes Q, mediate
  electron-transfer processes involved in energy
  production through their redox reactions

114
12. Spectroscopy of Alcohols and Phenols

• Alcohols and phenols can be identified by
• Infrared Spectroscopy
• Nuclear Magnetic Resonance Spectroscopy
• Mass Spectrometry

115
Infrared Spectroscopy

• Alcohols have a characteristic OH stretching
  absorption at 3300 to 3600 cm-1 in the IR
  spectrum
• Sharp absorption near 3600 cm-1 except if
  H-bonded then broad absorption 3300 to 3400 cm-1
  range
• Strong CO stretching absorption near 1050 cm-1

Cyclohexanol
116

• Phenol OH absorbs near 3500 cm-1

117
Practice Problem Assume that you need to
prepare 5-cholestene- 3-one from
cholesterol. How could you use IR
spectroscopy to tell whether the reaction was
successful? What differences would you look
for in the IR spectra of starting
material and product?
118
Nuclear Magnetic Resonance Spectroscopy

• 13C NMR C bonded to electron-withdrawing -OH is
  deshielded and absorbs at a lower field, ? 50 to
  80

119

• 1H NMR H bonded on the O-bearing C is deshielded
  by electron-withdrawing effect of the nearby O
  it absorbs at ? 3.5 to 4.5
• Usually no spin-spin coupling between OH proton
  and neighboring protons on C due to exchange
  reactions with moisture or acids
• Spinspin splitting is observed between protons
  on the oxygen-bearing carbon and other neighbors
• Phenol OH protons absorb at ? 3 to 8

120

• Usually no spin-spin coupling between OH proton
  and neighboring protons on C due to exchange
  reactions with moisture or acids

Adding D2O makes the OH proton absorption
disappear
121

• Spinspin splitting is observed between protons
  on the oxygen-bearing carbon and other neighbors
• Example 1-propanol

122
Practice Problem When the 1H NMR spectrum of an
alcohol is run in DMSO solvent rather
than chloroform, exchange of the OH
proton is slow and spin- spin splitting
is seen between the OH proton and CH
protons on the adjacent carbon. What
spin multiplicities would you expect for the
hydroxyl protons in the following alcohols?

• 2-Methyl-2-propanol
• Cyclohexanol
• Ethanol

• 2-propanol
• Cholesterol
• 1-Methylcyclohexanol

123
Mass Spectrometry

• Alcohols undergo
• alpha (?) cleavage, a CC bond nearest the
  hydroxyl group is broken, yielding a neutral
  radical plus a charged oxygen-containing fragment
• dehydration, loss of H-OH yielding an alkene
  radical cation

124

• alpha (?) cleavage a CC bond nearest the
  hydroxyl group is broken, yielding a neutral
  radical plus a charged oxygen-containing fragment

125

• Dehydration loss of H-OH yielding an alkene
  radical cation

126

• Example Mass spectrum of 1-butanol

127
Chapter 17
The End