Synthesis, composition, and properties of products formed in interaction of ortho-tert-butylphenol with sulfur monochloride

Article abstract of DOI:10.1134/S1070427209110123

Interaction of ortho-tert-butylphenol with sulfur monochloride in dimethylformamide leads to an increase in the fraction of phenol di- and polysulfides in the product. Liquid chromato-mass-spectrometry was used to determine the composition of the main gro

Full text of DOI:10.1134/S1070427209110123

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 11, pp. 1965−1969. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © A.P. Krysin, T.G. Egorova, N.I. Komarova, V.G. Vasil’ev, L.M. Pokrovskii, 2009, published in Zhurnal Prikladnoi Khimii, 2009,
Vol. 82, No. 11, pp. 1817−1821.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Synthesis, Composition, and Properties of Products Formed
in Interaction of ortho-tert-Butylphenol
with Sulfur Monochloride
A. P. Krysin, T. G. Egorova, N. I. Komarova, V. G. Vasil’ev, and L. M. Pokrovskii
Vorozhtsov Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Received February 18, 2009
Abstract—Interaction of ortho-tert-butylphenol with sulfur monochloride in dimethylformamide leads to
an increase in the fraction of phenol di- and polysulfides in the product. Liquid chromato-mass-spectrometry was
used to determine the composition of the main groups of compounds contained in the mixture. A number of its
components was isolated and produced by counter synthesis.
DOI: 10.1134/S1070427209110123
The stabilizer Tioalkofen-B (TAB) is the contracted
name of the product formed in the reaction of ortho-
tert-butylphenol (OTBP) with sulfur monochloride.
Its properties strongly depend on whether mono- or
polysulfides are predominant in its mixture and,
consequently, on the method and conditions of its
synthesis.
prolonged keeping of articles in water [3]. TAB has been
successfully used to solve one of the most complicated
problems of creating reliable coatings for protection
of microelectronic devices from any external factors,
including radiation [4].
The aim of our study was to examine the composition
of TAB and find its synthesis conditions providing the
maximum efficiency as a modifier of service properties of
composite polymers. To raise the fraction of “disulfides”
in the reaction of phenols with sulfur monochlorides, it
has been recommended to perform the process in a flow
of hydrogen sulfide [5], employ iodine and powdered iron
as a catalyst [6], and use basic solvents DMFAand DMSO
[7], with the last way being the most effective.
Astudy of the thermolysis kinetics of mono-, di-, and
trisulfides of phenols and of their practical properties has
shown that mono- and polysulfides of phenols belong to
antioxidant groups differing in their action: monosulfides
of phenols are additives that are extractable from
polymers and do not noticeably change their properties.
Phenols containing a chain of two or more sulfur atoms
in their structure can, under certain thermal treatment
conditions, behave either as antioxidants or as effective
modifiers of properties of polymeric materials. TAB
belongs to the second group. Introduction of TAB into
a formulation containing low-pressure polyethylene and
a cross-linking agent of the peroxide type improves the
stability of the composite being formed against action
of elevated temperatures and leads to an increase in
deformation characteristics and to preservation of thermal
stability upon a contact with solvents [2]. Introduction of
0.5 to 1.5% TAB into a formulation of a glass-fiber plastic
based on epoxy phenol-formaldehyde resin improves
its strength and water resistance under conditions of
The attractiveness and accessibility of the starting
reagents, phenols and sulfur monochloride, and the most
favorable conditions of their interaction are known,
but it is difficult to find in organic chemistry a reaction
more complex, ambiguous, and poorly studied than the
reaction in question [8]. The expected disulfides are
contained in reaction mixtures in amounts smaller than
30%, and it is impossible to isolate these compounds by
simple methods from a reaction mass with a complex
composition. Previously, we have made an attempt
to study the composition of products formed in the
interaction of OTBP with sulfur monochloride by GLC
1965

1966
KRYSIN et al.
[9]. This technique, which, as a rule, requires heating of
high-boiling samples to a temperature of 300°C, failed
to furnish an objective picture because of the complex
composition of the mixture of products being formed, and
primarily due to the poor thermal stability of polysulfides
of phenols: their noticeable decomposition is observed
at temperatures of 140°C and higher [10]. It has been
suggested to analyze the composition of a mixture of
2,6-di-tert-butylphenol polysulfides by liquid chromato-
mass-spectrometry [11], and this technique became the
basis of analytical studies.
Synthesis of TAB in DMF. To a solution of 300 g
(1.96 g mol–1) of 98% OTBP in 250 ml of DMF,
cooled to –20°C is added, under vigorous stirring in
the course of 2 h, 88 ml (148 g, 1.1 g mol–1) of freshly
distilled sulfur monochloride in such a way that the
reaction mass temperature does not exceed –5°C. The
mixture is kept at room temperature for 2 h and, with
agitation continued, heated to 50°C, which results in
that a homogeneous mass is formed. It is dissolved in
1 l of methyl-tert-butyl ether, the solution is washed
with a threefold amount of water, and the solvent is
evaporated. This yields 340 g of a highly viscous light
yellow transparent oil (TAB), which contains, according
to GLC data, 1% solvent. On being heated to 50°C, the
oil becomes thin.
EXPERIMENTAL
When the reaction of OTBPwith S2Cl2 was performed
without a solvent and with hexane, nitromethane, and
acetonitrile, the compositions of the products formed were
approximately the same. In each case, monosulfide (1)
was quantitatively predominant over other components
and its content was 30 to 45%. An example of synthesis
of TAB in toluene was described in the patent [11].
Performing this reaction in DMFA sharply changed the
composition of the reaction mass.
To determine the molecular masses and the elemental
composition of TAB components, we used a Finnigan
MAT 8200 high-resolution mass spectrometer. Separate
components in the reaction masses were identified using
aTsvet gas chromatograph. The composition of TAB
and its separate components was analyzed by NMR.
The melting points were determined with a Kцfler
apparatus.
Scheme.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 82 No. 11 2009

PROPERTIES OF PRODUCTS FORMED IN INTERACTION OF ortho-tert-BUTYLPHENOL
1967
The data presented below demonstrate that the
content of monosulfide (1) decreased from 40 to 12% and
p,p- di- and polysulfides (2)–(5) of 2-tert-butylphenol
predominate: the total content of these compounds is
about 70%. Compounds 6–9, contained in an amount
of 6%, are a mixture of o,p- mono- and polysulfides of
2-tert-butylphenol.Another group is constituted by ~10%
sulfur-containing compounds 11–16, each containing
three 2-tert-butylphenol fragments. Also, chlorine-
containing compounds were identified in TAB in minor
amounts. These are represented by compound 10 (see
the Scheme).
m/z 330.16347. C20H26O2S. Calculated: m/z 330.16347.
Using this method, we also isolated from the mixture
individual compounds 1 and 2, which were produced
by counter synthesis. Mercaptan 17 was obtained by
reduction of TAB with hydrogen, one of the most effective
catalysts for reduction of du- and polysulfides to obtain
mercaptans [12].
4-Mercapto-2-tert-butylphenol (17). A 0.5-l
Vishnevskii autoclave was charged with 5 g of IK-75-
01 catalyst (1% mixture of freshly prepared Co, Mn, B,
and K sulfides on a carbon support in the form of small
globules) and 180 g of a TAB stabilizer synthesized in
DMF by the method described above. The autoclave
was purged with hydrogen and then a hydrogen pressure
of 2 MPa was created in the device. The reaction mass
was kept under vigorous agitation at 160°C for 20 h. On
cooling the autoclave, the reaction mass is filtered to
remove the recyclable catalyst and the filtrate is extracted
with 800 ml of a 5% caustic soda solution. The aqueous
alkaline extract is separated from the organic layer and
acidified with hydrochloric acid, and the product is
extracted with ether. After evaporating the solvent, the
oil obtained is distilled in a vacuum and the fraction with
bp 145–152°C/3–4 mm Hg is collected. The yield of
4-mercapto-2-tert-butylphenol (17) is 130 g at a content
of the main substance equal to 92% according to GLC.
In the first stage of the study, we separated TAB into
components by HPLC on a Milikhrom-1 microcolumn
liquid chromatograph (2 Ч 64 mm column, stationary
phase Nucleosil 100-5018, particle size 5 μm, Macherey–
Nagel, Germany) [13].A85 : 15 mixture of methanol and
water with addition of a 1% acetic acid solution served as
the mobile phase. The elution rate was 100 μl min–1.
Substances were detected with a UV detector at
five wavelengths simultaneously. The chromatographic
information was recorded and processed with a CHROM
versatile computerized data acquisition and processing
system. The purity of compounds 1–4 and 6, isolated as
described above, was not worse than 97% according to
GLC.
Bis-(3-tert-butyl-4-hydroxyphenyl)trisulfide (3).
Oil: PMR spectrum (200 MHz, CCl4, σ, ppm): 1.38 s
(C4H9-tert), 4.96 s (–OH), 6.55 d (J = 7.5 Hz, H6-
arom), 7.31 d.d (J' = 7.5 Hz, J'' = 1.5 Hz, H5-arom),
7.49 d (J = 1.5 Hz, H3-arom). Found MM (by mass
spectrometry): m/z 394.10749. C20H26O2S3. Calculated:
m/z 394.10749.
Bis-(3-tert-butyl-4-hydroxyphenyl)disulfide (2).
A 10-g portion of 4-mercapto-2-tert-butylphenol (16)
and 1 g of KOH are dissolved in 30 ml of isopropanol,
and air is bubbled through a boiling mixture for 6 h,
with the composition of the reaction mass monitored
by GLC. Then, the solvent is removed and the residue
is washed with water to a neutral reaction to give 8 g of
a light yellow oil. The oil mostly contains bis-(3-tert-
butyl-4-hydroxyphenyl)disulfide (2), which is purified
by column chromatography. PMR spectrum (200 MHz,
CCl4, σ, ppm): 1.37 s (C4H9-tert), 5.05 s (–OH), 6.58 d
(J = 8.5 Hz, H6-arom), 7.21 d.d (J' = 8.5 Hz, J'' = 2.5 Hz,
H5-arom), 7.40 d (J = 2.5 Hz, H3-arom). Found MM (%):
C 66.48, H 7.40, S 17.91. C20H26O2S2. Calculated (%)
C 66.26, H 7.23, S 17.69.
Bis-(3-tert-butyl-4-hydroxyphenyl)tetrasulfide (4).
Oil: PMR spectrum (200 MHz, CCl4, σ, ppm): 1.39 s
(C4H9-tert), 5.00 s (–OH), 6.61 d (J = 9.0 Hz, H6-arom),
7.31 dd (J’ = 9.0 Hz, J'' = 2.3 Hz, H5-arom), 7.53 d (J =
2.3 Hz, H3-arom).
Found MM (by mass spectrometry): m/z 426.07734.
C20H26O2S4. Calculated: m/z 426.07734.
Bis-1,2'-(3-tert-butyl-4-hydroxyphenyl)(6'-tert-
butyl-1'-hydroxyphenyl)sulfide (6). Oil: PMR spectrum
(200 MHz, CCl4, σ, ppm): 1.30 s (C4H9-tert, C6'), 1.39 s
(C4H9-tert, C2), 5.15 s (–OH, C'), 6.51 d (J = 8.5 Hz, H6-
arom), 6.79 d.d (J’= 8.5 Hz, J'' = 1.5 Hz, H5-arom), 6.84
m (H4-arom), 6.95 d (J = 2.5 Hz, H3-arom), 7.31 d.d (J' =
8.0 Hz, J'' = 1.5 Hz, H5-arom), 7.39 d.d (J’= 8.0 Hz, J'' =
2.0 Hz, H3-arom). Found MM (by mass spectrometry):
Bis-(3-tert-butyl-4-hydroxyphenyl)sulfide (1).A50-
ml portion of toluene is placed in 0.5-l flask and cooled
to –15°C. Simultaneously, 102 ml (0.67 g mol–1) of
2-tert-butylphenol in 100 ml of toluene and 21 ml (0.33 g
mol–1) of sulfur dichloride in 50 ml of toluene are added
from two dropping funnels at a rate at which the reaction
mass temperature does not exceed 0°C.After the dropping
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1968
KRYSIN et al.
working parameters of mass detection were as follows:
ionization by electrostatic spraying under atmospheric
pressure (API-ES), scanning of negative ions in the range
m/z = 120–1000, flow rate of the drying gas (nitrogen)
8 l min–1, its temperature 230°C, spraying gun pressure
1.6 Bar, accuracy of molecular mass determination
0.01 Da. Peaks of substances contained in the mixture in
amounts exceeding 1% were analyzed. Compounds of this
kind constituted 94% of all TAB components.
addition is complete (in ~1 h), the reaction mass is kept
at room temperature for 2 h and then is again cooled
to –15°C, with the resulting precipitate filtered-off and
washed with petroleum ether cooled to 0°C. This yields
52 g (47%) of bis-(3-tert-butyl-4-hydroxyphenyl)sulfide
in the form of a white powder, mp 105–110°C. PMR
spectrum (200 MHz, CCl4, σ, ppm): 1.35 s (C4H9-tert),
4.84 s (–OH), 6.64 d (J = 8.5 Hz, H6-arom), 7.05 d.d
(J' = 8.5 Hz, J'' = 2.5 Hz, H5-arom), 7.27 d (J = 2.5 Hz,
H3-arom). The isolation of individual components from
TAB in the first part of the study made us confident in
the structure of p,p-linked products and served as the
necessary stage in a full analysis of products contained
in TAB.
The use of a high-resolution time-of-flight mass
detector in the system with the HPLC-MS instrument
made it possible to precisely determine empirical
formulas of all the TAB components and, in combination
with UV spectroscopic and mass-spectrometric data, to
obtain information about their structure. Previously, it
has been impossible to obtain such a vast body of data in
analyses of sulfur-containing phenols [12]. The results of
our HPLC-MS analysis are listed in the table.
The structures of all the components of TAB were
found by using a new HPLC-MS system. The system
included an Agilent 1200 liquid chromatograph with
a diode-array detector and a Bruker micrOTOF-Q hybrid
quadrupole time-of-flight mass spectrometer; Zorbax
XDB-C8 column, 2.1 × 150 mm, 3.5 μm, eluent 2%
HCOOH–MeOH (15 : 85 v/v), flow rate 0.2 ml min–1,
UV detection at three wavelengths. Every second of the
UV spectra accessible to the system (150 spectra per
minute) in the range 230–450 nm was recorded. The
Four types of compounds were identified in the
mixture.
The first type has a general empirical formula
C20H26O2Sn. To this type belong the already known
compounds 1–4 and, judging from the mass of the
phenolate anion and closeness of the UV spectrum, we can
Results of an HPLC-MS analysis of the composition of products formed in the interaction of 2-tert-butylphenol with S2Cl2
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 82 No. 11 2009

PROPERTIES OF PRODUCTS FORMED IN INTERACTION OF ortho-tert-BUTYLPHENOL
1969
reliably class with the same type the peak with RT = 12.05
and attribute structure 5 to this peak. A characteristic
feature of this group of compounds is the form of the mass
spectrum.As follows from the data in the table, the signal
of the phenolate anion (M–H+) has the highest intensity
in the spectra of this group of compounds.
three ortho-tert-butylphenol fragments connected by two
mono- or polysulfide bridges, and the fourth, by chlorine-
containing products.
(2) Use of dimethylformamide as a solvent in this
reaction leads to an increase in the fraction of polysulfides
of phenols in Tioalkofen-B.
We attributed the second set of peaks with the same
empirical formula C20H26O2Sn, but noticeably different
peak intensities and spectra to a mixture of o,p- mono- and
polysulfides of 2-tert-butylphenol [structures 6–9, peaks
with RT = 6.56, 7.82, 21.16, and 25.65]. A characteristic
feature of this group of compounds is the shift of peaks in
UV spectra to shorter wavelengths, compared with the UV
spectra of the isomers from the first group. Under mass-
detection conditions, these compounds give fragment-ion
signals of substantially higher intensity, compared with
the signals of the isomers from the first group. Presumably,
this points to a higher lability of the phenolate (M–H+)
of ortho-di- and polysulfides of phenols, compared with
the anions of their para-isomers.
REFERENCES
1. Nikulicheva, O.N., Krysin, A.P., and Fadeeva, V.P., Zh.
Prikl. Khim., 2008, vol. 81, no. 9, pp. 1517–1522.
2. USSR Inventor’s Certificate, no. 1735326.
3. USSR Inventor’s Certificate, no. 1657517.
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5. French Patent 1369616.
6. Japan Patent 04 283560.
7. Europe Patent 200212.
To the third set of peaks (RT = 1.0, 12.27, 13.92, 14.31,
15.84, and 17.93) corresponds the empirical formula
C30H38O3Sn. The form of the UV and mass spectra
corresponding to these peaks is in better agreement with
structures 11–16.
8. Brezhneva, L.I., Vasilevskaya, T.I., Andrievskii, V.N.,
and Maksimov, I.E., Zh. Org. Khim., 1981, vol. 17, no. 9,
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Reagents for Polymeric Materials”),. Tambov, 1990,
p. 17.
Judging from the anion mass and isotropic distribution,
to the peak with RT = 5.41 (fourth type) can correspond
the only empirical formula C20H25O2SCl. The specific
features of the spectra corresponding to this peak attribute
to it structure 10.
10. Nikulicheva, O.N., Pokrovskiy, L.M., Krysin, A.P.,
et al., J. Therm. Anal. Calorimetry, 2000, vol. 60, pp.
157–161.
CONCLUSIONS
11. Bukharov, S.V., Konashenko, L.V., Solov’eva, S.E., et al.,
(1) The mixture of compounds produced by interaction
of ortho-tert-butylphenol with monochloride sulfur
contains four groups of products; two of these are p,p-
and o,p-mono- and polysulfides of ortho-tert-butylphenol,
the third group is constituted by compounds containing
Zh. Prikl. Khim., 1999, vol. 72, no. 4, pp. 641–644.
12. RF Patent 2184727.
13. Baram, G.J., Grachev, M.A., Komarova, N.I., el. al.,
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