Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 1, pp. 42−47.
Pleiades Publishing, Ltd., 2014.
Original Russian Text E.N. Cherezova, F.B. Balabanova, D.P. Shalyminova, S.Sh. Saigitbatalova, A.G. Liakumovich, 2014, published in Zhurnal Prikladnoi
Khimii, 2014, Vol. 87, No. 1, pp. 46−51.
AND INDUSTRIAL ORGANIC CHEMISTRY
Synthesis and Prospects for Use as Stabilizer
for Ethylene–Propylene Rubber
E. N. Cherezova, F. B. Balabanova, D. P. Shalyminova,
S. Sh. Saigitbatalova, and A. G. Liakumovich
Kazan National Research Technological University, ul. Karla Marksa 68, Kazan, Tatarstan, 420015 Russia
Received August 20, 2014
Abstract—A phenolic antioxidant was synthesized by the reaction of N,N-dimethyl(3,5-di-tert-butyl-4-hydroxy-
benzyl)amine with cyclohexanone.
The inﬂ uence of temperature, reactant ratio, pressure, and time on the yield of
the product, 2,6-bis(3,5-di-tert-butyl-4-hydroxybenzyl)cyclohexanone, was examined. The antioxidant obtained,
taken both separately and in synergistic mixtures with alkylphenol and phosphites, showed high performance in
inhibition of the thermal aging of ethylene–propylene rubber.
Phenolic antioxidants (PAOs) are widely used as
nonstaining stabilizers for polymers [1–6]. These agents
terminate oxidation chains by the reaction of phenolic
hydroxyl with peroxy radicals (InH + ROO
ROOH). Despite the structural diversity of the pheno-
lic compounds described, only a very limited number
of them are used as PAOs because of the difﬁ cult avail-
ability of the raw materials and lack of commercially
acceptable production technologies. Therefore, it is nec-
essary to search for effective PAOs that can be prepared
by easy-to-implement processes from readily available
The majority of PAOs contain a 3,5-di-tert-butyl-
4-hydroxyphenyl fragment in their structure . Such
fragment can be introduced, in particular, using N,N-
reactive agent . A series of effective PAOs have been
developed on its basis. Syntheses involving this com-
pound occur under relatively mild conditions with good
This study is aimed to expand the range of PAOs pre-
pared using N,N-dimethyl(3,5-di-tert-butyl-4-hydroxy-
benzyl)amine (Mannich Base, MB). Our approach was
based on the concept of priority formation of bisphe-
nolic PAOs, which are considerably less volatile than
monophenolic AOs and exhibit high performance.
As a rule, dialkyl-substituted phenolic fragments are
linked in bisphenolic AOs by bridges of various struc-
tures. As starting reagent for the formation of the bridge,
we used commercially available cyclohexanone (CH). Its
incorporation into the stabilizer structure can be expected
to enhance the stabilizer performance owing to the addi-
tionally arising inhibition route, scavenging of alkyl radi-
cals initially generated in the course of the polymer aging,
because it is known that lactones and cyclic ketones react
with alkyl radicals at high rates [9, 10].
The reaction of MB with CH was performed in a
round-bottomed ﬂ ask equipped with a stirrer, a bubbler,
a reﬂ ux condenser, and a thermometer. The ﬂ ask was
charged with the calculated amount of the reactants,
and the temperature was elevated to 135–145°С. The