Russian Journal of Applied Chemistry, Vol. 77, No. 8, 2004, pp. 1382 1385. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004,
pp. 1395 1397.
Original Russian Text Copyright
2004 by O. Klyuchnikov, Khairutdinov, Ya. Klyuchnikov.
MACROMOLECULAR CHEMISTRY
AND POLYMERIC MATERIALS
Preparation and Vulcanizing Properties
of 1,3,5-Trinitrosobenzene
O. R. Klyuchnikov, F. G. Khairutdinov, and Ya. O. Klyuchnikov
Kazan State Technological University, Kazan, Tatarstan, Russia
Received May 11, 2004
Abstract A procedure was developed for preparing a new trifunctional vulcanizing agent for unsaturated
rubber composites, 1,3,5-trinitrosobenzene; its suitability as an additive to rubber substrate adhesive
formulations was examined.
Dinitrosoarenes are used as highly active vulcaniz-
ing agents for unsaturated rubbers and composites
thereof [1]; p-dinitrosobenzene (DNB) is widely used
in rubber substrate adhesive formulations [2]. The
curing power of dinitrosoarenes is based on their bi-
functional structure allowing cross-linking of two un-
saturated rubber molecules. Calculations predict [3]
that 1,3,5-trinitrosobenzene (TNB) should be more
reactive in vulcanization than DNB. Therefore, syn-
thesis of trifunctional TNB is of theoretical and ap-
plied interest.
oxidation to TNB. Addition of a small amount of
sodium nitrite as a source of nitrogen oxides initiates
oxidation of CTO to TNB; thus, NO2 and N2O4 are
key compounds in the reaction.
EXPERIMENTAL
Cyclohexane-1,3,5-trione trioxime was prepared as
described in [4].
1,3,5-Trinitrosobenzene. Dilute nitric acid was
prepared by adding 16 ml of 98% HNO3 containing
0.2 0.4% nitrogen oxides to 50 g of ice. To the re-
sulting 35% HNO3 solution containing dissolved ni-
trogen oxides ( 0.1%), 1.0 g of CTO was added with
vigorous stirring at 12 15 C. Virtually immediately
after the dissolution of CTO, TNB was formed as
a hydrophobic foam. The product was filtered off,
washed with water to neutral reaction and then with
acetone, and dried. Yield 0.32 g (34%); light tur-
quoise powder, mp 170 C with decomposition. No
tarring was observed. Analytical data:
The goal of this study was to develop a facile pro-
cedure for preparing TNB and to evaluate its vulcaniz-
ing properties and adhesive power in rubber substrate
formulations.
The initial attempts to prepare TNB by reduction of
1,3,5-trinitrobenzene to 1,3,5-tri(hydroxylamino)ben-
zene, followed by oxidation, failed because of side
reactions yielding azo and azoxy derivatives. Another
route led to success: oxidation of cyclohexane-1,3,5-
trione trioxime (CTO) with 30 35% HNO3 in the
presence of minor amounts ( 0.1%) of nitrogen ox-
ides. In the course of the reaction, TNB is formed as
a hydrophobic foam:
Found, %: C 43.90, N 25.20, H 1.65.
C6H3N3O3.
Calculated, %: C 43.65, N 25.45, H 1.83.
NOH
NO
The mass spectrum (EI, 70 eV) recorded on
a Finnigan MAT-212 device showed that the sam-
ple completely sublimed on being introduced into the
ion source. Mass spectrum, m/z (Irel, %): 165.1
[M]+ (59), 135 [M NO]+ (42), 105.1 [M NO NO]+
(8), 75.1 [M NO NO NO]+ (100). The fragmenta-
HNO3(NO)2
HON
NOH
ON
NO
In dilute nitric acid free of nitrogen oxides, CTO
readily dissolves to form a brown solution, without
1070-4272/04/7708-1382 2004 MAIK Nauka/Interperiodica