1070-4272/05/7807-1110+2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 7, 2005, pp. 1110 !1114. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 7,
2005, pp. 1130!1134.
Original Russian Text Copyright + 2005 by Bashkatova, Miryasova, Cherezova, Bukharov.
AND INDUSTRIAL ORGANIC CHEMISTRY
Synthesis and Antioxidative Properties
of Bis(3,5-di-tert-butyl-4-hydroxyphenyl) Polysulfides
T. V. Bashkatova, F. K. Miryasova, E. N. Cherezova, and S. V. Bukharov
Kazan State Technological University, Kazan, Tatarstan, Russia
Received March 4, 2005
Abstract-An efficient procedure was developed for preparing bis(3,5-di-tert-butyl-4-hydroxyphenyl) poly-
sulfides in the presence of phenolic Mannich bases. The antioxidative activity of the resulting bis(polysulfides)
in rubbers of various structures and in their vulcanizates was examined.
Sterically hindered phenols (SHPs) find growing
use for antioxidative stabilization of polymeric materi-
als, thanks to the strong protective effect of SHPs and
their low toxicity. Today the researchers’ attention is
focused on molecular structures containing, along
with an SHP moiety, also additional groups or atoms
suppressing the radical-chain oxidation in various
steps and by different mechanisms [1, 2]. Such stabi-
lizers can exhibit intramolecular synergism and sub-
stantially surpass in the antioxidative performance
classical mixed synergistic stabilizing systems .
Among polyfunctional SHP antioxidants are com-
pounds containing simultaneously SHP fragments and
sulfide groups [1, 3].
SHP sulfides were prepared previously by reactions
of 2,6-dialkylphenols with S
ever, this route has certain disadvantages: relatively
low yield of the target product, formation of a large
amount of the by-product, and release of hydrogen
chloride contaminated with sulfur chlorides. SHP
polysulfides can also be prepared using elemental
sulfur. According to , the reactions of SHPs with
sulfur are performed in the presence of an at least
equimolar amount of alkali relative to 2,6-dialkyl-
phenol and of a large excess of sulfur. This makes
the process technologically unfeasible, because of the
necessity of utilizing large amounts of acidic aqueous-
organic wastes. However, the procedure for preparing
SHP polysulfides using elemental sulfur is attractive
in connection with the pressing problem of utilization
of [gas] sulfur, a by-product of hydrorefining of crude
oil and hydrocarbon raw materials.
The goals of this study were to develop a feasible
procedure for preparing sterically hindered phenol
sulfides by the reaction of 2,6-dialkylphenol with
elemental sulfur and to examine their antioxidative
(AO) performance in various rubbers and polymeric
materials based on them.
The following chemicals were used in the study.
2,6-Di-tert-butylphenol. White crystals, mp 363
37oC, MW 206. Readily soluble in benzene, acetone,
Sulfur. mp 112.8oC, density 196032070 kg m
A yellow crystalline solid, insoluble in water, sparing-
ly soluble in alcohol and ether, and readily soluble in
carbon disulfide. The molecular weight of sulfur at
low temperatures corresponds to the formula S
2-Dimethylaminomethylphenol. A light yellow
liquid; it contained a 1.88% impurity of phenol.
2,6-Bis(dimethylaminomethyl)phenol. A light
yellow liquid; it contained a 2.4% impurity of phenol.
mp 93395oC (from acetone). MW 263. White or
slightly yellowish crystals soluble in the majority of
FF). mp 152oC. MW 310. Dark gray crystalline pow-
der; soluble in alcohols, acetone, benzene, chloroform,
xylene, aniline, and chlorobenzene; insoluble in
Acetone anil P (C
. An oligomer of 2,2,4-
trimethyl-1,2-dihydroquinoline. mp 65375oC. MW
4003500. Soluble in chloroform, benzene, alcohols,
and acetone; insoluble in water.