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O
Na
2
WO
4
(0.2%)
OH
+ 4H
2
O
+ 4H
2
O
2
HO
[CH
3
(
n-
C
8
H
17
)
3
N]HSO
4
O
75-90
°
C, 8 h
yield 93%
O
OH
[O]
H
2
O
[O]
O
OH
OH
O
[O]
[O]
H
2
O
OH
HO
O
O
O
O
HO
O
O
Scheme 10.62
of 2,6-diisopropylnaphthalene were prepared simi-
larly [445].
Similar auto-oxidations of cyclohexene, tetralin
and cumene were studied by Csanyi & Jaky [446],
who concluded that the role of the phase-transfer
catalyst is to facilitate homolysis of the O-O bond
of the hydroperoxide. Accordingly, Aliquat 336
was utilised for the selective decomposition of
primary hydroperoxides in the presence of tertiary
hydroperoxides with very high selectivity [447].
Auto-oxidation of g-picoline to nicotinic acid was
carried out by a combined Co/Mn/tetra-
n
-
propylammonium bromide (TPAB) catalyst (Scheme
10.66) [448]. Anionic monomeric and oligomeric
vanadium (V) species could be extracted into the
t
-
butylhydroperoxide organic phase using Aliquat
336. These ion pairs influenced the decomposition
rate of TBHP and catalysed the auto-oxidation of
hydrocarbons [449].
In a patent from Dow Agrosciences [450] the
oxidation by chlorine of the following disulfide to
sulfonyl chloride is disclosed (Scheme 10.67).
Disulfides could be prepared from thiols via bromi-
nation with tetrabromomethane in the presence
of potassium carbonate and 18-crown-6 [451].
Phenylindenes were dimerized via chloro intermedi-
ates using tetrachloromethane or hexachloroethane
in the presence of 50% aqueous KOH and TEBA
[452]. Aliphatic hydrocarbons could be brominated
Cl
Cl
Cl
Cl
35% H
2
O
2
, Toluene
TEBA, NaHCO
3
Cl
N
NHNH
2
Cl
N
93% yield
Scheme 10.63
phenylethylhydroperoxide for the oxidation of
cumene catalysed by copper combined with
crown ether. We have converted tetralin to 1-
(
t
-butylperoxy)tetralin by reaction with
t
-
butylhydroperoxide/TBAB/CuCl
2
[442]. The same
bi-functional catalytic system was studied also in the
oxidation of alcohols (Scheme 10.64) [443].
9.2 Other oxidising agents
The application of quaternary ammonium salts as
single-component auto-oxidation catalysts was
extended to various substrates. In a patent from
Osaka Gas (Scheme 10.65), the TBAB-catalysed
peroxidation of isopropylbiphenyl followed by
acid decomposition of the hydroperoxide to 4-
phenylphenol was disclosed [444]. Hydroperoxides
