Synthesis of new primary-tertiary alkyl bisperoxides by reaction of tertiary hydroperoxides with bromoalkanes in a PTC system

Article abstract of DOI:10.1007/s007060170069

Syntheses of novel primary-tertiary bisperoxides were carried out under phase transfer catalysis conditions. The bisperoxides were obtained in good yields, the reaction times not exceeding four hours.

Full text of DOI:10.1007/s007060170069

Monatshefte fuÈr Chemie 132, 821±824 (2001)
Synthesis of New Primary-Tertiary Alkyl
Bisperoxides by Reaction of Tertiary
Hydroperoxides with Bromoalkanes
in a PTC System
Ã
Jan Zawadiak , Mirosøaw Danch, and Mariola Pigulla
Institute of Organic Chemistry and Technology, Silesian University of Technology Gliwice, PL-44100
Gliwice, Poland
Summary. Syntheses of novel primary-tertiary bisperoxides were carried out under phase transfer
catalysis conditions. The bisperoxides were obtained in good yields, the reaction times not exceeding
four hours.
Keywords. Peroxides; Initiators; PTC.
Introduction
In recent years the production of chemicals displayed a noticeable increase,
particularly the production of ®ne chemicals. A considerable part of this kind of
production comprises auxiliary substances applied in the synthesis and processing
of plastics. Representatives of this group are organic peroxides which are used as
polymerization initiators and crosslinking agents [1]. Recently, growing interest in
compounds containing several peroxide and/or azo groups has been observed [2].
These compounds may be used as precursors in the free-radical synthesis of block
and graft copolymers.
One method to prepare alkyl peroxides is based on phase transfer catalysis
[3, 4]. These reactions are characterized by high ef®ciency and selectivity, accom-
panied by a shortening of the reaction time compared to analogous reactions carried
out in homogeneous systems. It was the purpose of this investigation to synthesize
new primary-tertiary alkyl bisperoxides (Scheme 1) under phase transfer catalysis
conditions.
Results and Discussion
Bisperoxides 5±8 were obtained by reaction of the sodium salts of cumene hydro-
peroxide (1) or 2-(1-hydroperoxy-1-methylethyl)-naphthalene (2) with 1,4-dibro-
mobutane (3) or 1,10-dibromodecane (4). The bisperoxides 12 and 13 resulted from
Ã
Corresponding author

822
J. Zawadiak et al.
Scheme 1
the reaction of the disodium salt of 1,4-bis-(1-hydroperoxy-1-methylethyl)-benzene
(9) with bromobutane (10) or benzyl bromide (11).
The synthesis of peroxides 5 and 6 in a homogenous system (anhydrous EtOH)
has been claimed in patents [5, 6]; the other peroxides are novel compounds. The
bisperoxides were obtained in satisfactory yields, especially when compared to those
obtained in homogenous systems. The reaction time of 4 hours was almost four
times shorter than that for similar reactions performed in homogenous systems [5].
Experimental
Bromobutane (10; 98%, P.P.H. POCh Gliwice), 1,4-dibromobutane (3; 98%, Merck), 1,10-
dibromodecane (4; 99%, Merck), benzyl bromide (13; 98%, Merck), tetra-n-butylammonium
hydrogensulfate (98%, Merck), and 1,4-bis-(1-hydroxy-1-methylethyl)-benzene (99%, Aldrich) were
used without further puri®cation. The results of elemental analyses agreed favourably with the
calculated values. NMR spectra were recorded on a Varian Inova 300 multinuclear NMR spectrometer
in CDCl3 using TMS as internal standard.
1,4-Bis-(1-hydroperoxy-1-methylethyl)-benzene
1,4-Bis-(1-hydroperoxy-1-methylethyl)-benzene was prepared from 1,4-bis-(1-hydroxy-1-methyl-
ethyl)-benzene by reaction with 63% H2O2 and H2SO4 as a catalyst. In a thermostatted 500cm3
round-bottomed ¯ask equipped with a thermometer, a mechanical stirrer, and a re¯ux condenser, 20 g
1,4-bis-(1-hydroxy-1-methylethyl)-benzene (103 mmol) and 200 cm3 toluene were heated to 50ꢀC;
then, a solution of 41 cm3 63% H2O2 (610 mmol) and 0.04 cm3 98% H2SO4 (8 mmol) was added in
small portions. The reaction was complete after 5 h. The precipitate was ®ltered off, washed with
H2O, a saturated solution of ꢁNH4†2SO4, and again with H2O. The crude product was then puri®ed by
recrystallization from benzene to give 20.73 g of a white solid (99%; m.p.: 146.5±147.5ꢀC; Ref. [7]:
m.p.: 147±152ꢀC).
Disodium salt of 1,4-bis-(1-hydroperoxy-1-methylethyl)-benzene (9; C12H16O4Na2)
A thermostatted 250 cm3 round-bottomed ¯ask equipped with a mechanical stirrer, a thermometer,
and a CaCl2 tube was charged with 5.56 g of 1,4-bis-(1-hydroperoxy-1-methylethyl)-benzene
(25 mmol) and 76 cm3 of anhydrous MeOH. The temperature of the mixture was lowered to 6ꢀC,

PTC Synthesis of Alkyl Bisperoxides
823
and 36 cm3 of a 15 M methanolic solution of NaOH (55 mmol) was added dropwise over 2 h. The
reaction mixture was then stirred at 6ꢀC for 30 min. After completion of the reaction, the crude
product was precipitated from acetone to give 3.12 g of a white hygroscopic crystalline solid (yield:
37%, purity: 98% based on iodometric analysis and acidimetric titration).
Sodium salt of cumene hydroperoxide (1), Sodium salt of 2-(1-hydroperoxy-1-methylethyl)-
naphthalene (2)
1 and 2 were obtained by reaction of an aqueous solution of NaOH (50%) with solutions of cumene
hydroperoxide (65% in toluene) and 2-(1-hydroperoxy-methylethyl)-naphthalene (46% in toluene) in
analogy to the methods described in Refs. [8] and [9].
Preparation of peroxides 5±8; general procedure
In an 80 cm3 thermostatted reactor ®tted with a magnetic stirrer, a re¯ux condenser, and a thermo-
meter, 10 mmol of the sodium salt of the hydroperoxide and 2 mmol of catalyst (tetrabutylammonium
hydrogensulfate) were dissolved in 10 cm3 of benzene or toluene. The bromoalkane (5 mmol) was
added dropwise at 20ꢀC under stirring, and the reaction mixture was then heated to 50ꢀC with stirring.
The progress of reaction was monitored by iodometric analysis (concentration of hydroperoxide) [10],
thin layer chromatography, and 1H NMR spectroscopy. After completion of the reaction, the mixture
was poured into 20 cm3 H2O, and the organic phase was separated, washed with H2O until Br was
absent (test with 0.01 M AgNO3), and ®nally dried over anhydrous MgSO4. After removal of the
solvent under vacuum, the crude material was puri®ed by column chromatography (silica gel, Merck,
70±230 mesh) using CHCl3 as eluent.
1,4-Bis-(1-methyl-1-phenylethyl-dioxy)-butane (5; C22H30O4)
1
Yield: 85%; n2D0: 1.5206; H NMR (CDCl3, ꢀ, 300 MHz): 7.46±7.24 (m, 10H, Har), 3.86 (t, J ˆ
5:5 Hz, 4H, ±O±O±CH2±CH2±), 1.57 (s, 12H, Ar±C(CH3)2±O±O±), 1.53 (t, J ˆ 5:5 Hz, 4H, ±O±O±
CH2±CH2±) ppm; 13C NMR (CDCl3, ꢀ, 75 MHz): 145.4, 128.0, 127.0, 125.4 (Car), 82.6 (Ar±
C(CH3)2±O±O±), 74.3 (±O±O±CH2±CH2±), 26.5 (±C(CH3)2±O±O±), 24.6 (±O±O±CH2±CH2±) ppm.
1,10-Bis-(1-methyl-1-phenylethyl-dioxy)-decane (6; C28H42O4)
Yield: 80%; n2D0: 1.5087; 1H NMR (CDCl3, ꢀ, 300 MHz): 7.48±7.22 (m, 10H, Har), 3.90 (t, J ˆ 6:6 Hz,
4H, ±O±O±CH2±CH2±), 1.58 (s, 12H, Ar±C(CH3)2±O±O±), 1.52 (m, 4H, ±O±O±CH2±CH2±), 1.20
(s, 12H, ±O±O±(CH2)2±(CH2)3±) ppm; 13C NMR (CDCl3, ꢀ, 75 MHz): 145.5, 128.0, 127.0, 125.5
(Car), 82.6 (±C(CH3)2±O±O±), 74.9 (±O±O±CH2±CH2±), 29.5, 29.4, 27.9, 26.2 (±O±O±CH2±
(CH2)4), 26.6 (±C(CH3)2±O±O±) ppm.
1,4-Bis-(1-methyl-1-(2-naphthyl)-ethyldioxy)-butane (7; C30H34O4)
Yield: 87%; m.p.: 44±47ꢀC; 1H NMR (CDCl3, ꢀ, 300 MHz): 7.83±7.41 (m, 14H, Har), 3.86 (t,
J ˆ 5:7 Hz, 4H, ±O±O±CH2±CH2±), 1.64 (s, 12H, Ar±C(CH3)2±O±O±), 1.52 (t, J ˆ 5:7 Hz, 4H, ±O±
O±CH2±CH2±) ppm; 13C NMR (CDCl3, ꢀ, 75 MHz): 143.0, 133.1, 132.4, 128.2, 127.6, 127.4, 125.9,
125.7, 124.2, 124.0 (Car), 82.7 (±C(CH3)2±O±O±), 74.4 (±O±O±CH2±CH2±), 26.5 (±C(CH3)2±O±O±),
24.6 (±O±O±CH2±CH2±) ppm.
1,10-Bis-(1-methyl-1-(2-naphthyl)-ethyldioxy)-decane (8; C36H46O4)
Yield: 85%; n2D0: 1.5504; 1H NMR (CDCl3, ꢀ, 300 MHz): 7.78±7.35 (m, 14H, Har), 3.84
(t, J ˆ 6:6 Hz, 4H, ±O±O±CH2±CH2±), 1.61 (s, 12H, Ar±C(CH3)2±O±O±), 1.45±1.02 (m, 16H,

824
J. Zawadiak et al.: PTC Synthesis of Alkyl Bisperoxides
±O±O±CH2±(CH2)4±) ppm; 13C NMR (CDCl3, ꢀ, 75 MHz): 143.0, 133.1, 132.5, 128.2, 127.6, 127.4,
125.9, 125.7, 124.2, 124.0 (Car), 82.7 (±C(CH3)2±O±O±), 74.5 (±O±O±CH2±CH2±), 29.7, 29.3, 27.9,
26.2 (±O±O±CH2±(CH2)4±), 26.6 (±C(CH3)2±O±O±) ppm.
Preparation of peroxides 12 and 13; general procedure
In an 80 cm3 reactor equipped with a magnetic stirrer, a re¯ux condenser, and a thermometer, 5 mmol
of the sodium salt of the dihydroperoxide and 1 mmol of catalyst were dissolved in 10 cm3 of benzene
or toluene. Then, 10 mmol of the bromoalkane were added dropwise at 20ꢀC, and the reaction mixture
was heated to 50ꢀC. Monitoring of the progress of the reaction and isolation of the product proceeded
as described above.
1,4-Bis-(1-butyldioxy-1-methylethyl)-benzene (12; C20H34O4)
1
Yield: 88%; n2D0: 1.5264; H NMR (CDCl3, ꢀ, 300MHz): 7.26 (s, 4H, Har), 3.92 (t, J ˆ 6:6 Hz, 4H,
±O±O±CH2±CH2±), 1.59 (s, 12H, Ar±C(CH3)2±O±O±), 1.59±1.50 (m, 4H, ±O±O±CH2±CH2±CH2±
CH3), 1.30±1.26 (m, 4H, ±O±O±CH2±CH2±CH2±CH3), 0.86 (t, J ˆ 7:3 Hz, 6H, ±O±O±CH2±CH2±
CH2±CH3) ppm; 13C NMR (CDCl3, ꢀ, 75 MHz): 144.1, 125.2 (Car), 82.6 (±C(CH3)2±O±O±), 74.7
(±O±O±CH2±CH2±CH2±CH3), 29.9 (±O±O±CH2±CH2±CH2±CH3), 26.5 (±C(CH3)2±O±O±), 19.3,
13.9 (±O±O±CH2±CH2±CH2±CH3) ppm.
1,4-Bis-(benzyldioxy-1-methylethyl)-benzene (13; C26H30O4)
1
Yield: 82%; m.p.: 48±51ꢀC; H NMR (CDCl3, ꢀ, 300 MHz): 7.43 (s, 4H, Har), 7.24±7.29 (m, 10H,
Har), 4.90 (s, 4H, ±O±O±CH2±Ph), 1.58 (s, 12H, Ar±C(CH3)2±O±O±) ppm; 13C NMR (CDCl3, ꢀ,
75 MHz): 144.0, 135.9, 129.0, 128.2, 128.1, 125.3 (Car), 82.9 (±C(CH3)2±O±O±), 77.1 (±O±O±CH2±
Ph), 26.5 (±C(CH3)2±O±O±) ppm.
Acknowledgements
The authors express their gratitude to the Polish State Committee for Scienti®c Research (Grant No. 3
T09B 046 18) as well as to RuÈtgers Kureha Solvents GmbH in Duisburg for ®nancial support.
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Received January 15, 2001. Accepted (revised) February 9, 2001