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Russian Journal of Applied Chemistry, Vol. 75, No. 5, 2002, pp. 854 !855. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 5,
2002, pp. 871!872.
Original Russian Text Copyright + 2002 by Sukhanov, Ivashkevich.
Mutual Transformations of Isomers
in N-Methyl-5-vinyltetrazole Copolymers
G. T. Sukhanov and O. A. Ivashkevich
Altai Federal Research and Production Center, Biisk, Altai krai, Russia
Received December 18, 2000
Abstract-Mutual transformations of N
isomeric derivatives of 5-vinyltetrazole polymers in the
absence of a solvent were studied.
Polymeric materials based on vinyltetrazoles exhib-
it a combination of unique properties, in particular,
high heat resistance (T = 2303380oC) at a high energy
up to 2800 kcal kg
, r = 1.323
1.5 g cm
) and a high nitrogen content (up to 65%)
, high sorption capacity for environmentally haz-
ardous ions of heavy and transition metals , and
physiological activity of some derivatives [3, 4].
Mutual transformations of 1,5 and 2,5 isomers of
disubstituted low-molecular-weight tetrazole deriva-
tives in solution are described in [5, 6]. Since the
physicochemical properties of tetrazoles are largely
dependent on the position of substituent at the nitro-
gen atom of the heteroring, it is important to study
possible mutual transformations of isomeric deriva-
tives of N-substituted 5-vinyltetrazole polymers.
When studying transformations occurring in a co-
polymer of 1-methyl-5-vinyltetrazole (1-MVT) and
2-methyl-5-vinyltetrazole (2-MVT) on storage and
heating in the absence of a solvent, we detected mutu-
al transformation of the 1-MVT and 2-MVT isomeric
units. At 20325oC, the relative content of the 2-MVT
units slowly grows. An equilibrium is attained at the
ratio 1-MVT : 2-MVT = 1 : 3. Prolonged heating at
80oC, on the contrary, results in a slow increase in the
1-MVT fraction (by 1% in 25330 h).
By analogy with the chemistry of tetrazole mono-
mers [5, 6], mutual transformations of N
isomers are facilitated by alkylating agents or by
formation of the corresponding tetrazolium salts.
Therefore, it can be suggested that, under polymeri-
zation conditions, N-methyl-5-vinyltetrazole units
undergo partial quaternization.
H NMR study of the products (PVT-M,
M-PVT, see below) formed in heterophase methyla-
tion of poly-5-vinyltetrazole (PVT) with dimethyl
sulfate showed that the spectrum of the M-PVT co-
polymer, along with the signals of the monomethy-
lated products (methyl groups of 1-MVT, 3.6 ppm,
and 2-MVT units, 4.2 ppm) , contains a weak sig-
nal at 4.6 ppm, which can be assigned  to the prod-
ucts of [second] exhaustive methylation with forma-
tion of N,N`-dimethyl-5-vinyltetrazolium methyl sul-
fate (TS) fragments.
The samples of poly-1-methyl-5-vinyltetrazole
(PMVT-1), poly-2-methyl-5-vinyltetrazole (PMVT-2),
PVT-M, and M-PVT prepared under conditions ex-
cluding formation of TS showed no evidence of mu-
tual transformation of the isomers under similar con-
ditions. Apparently, mutual transformation of 1-MVT
and 2-MVT units occurs via TS.
Polymers and copolymers of 1-MVT and 2-MVT
were prepared by two pathways: a sequence of poly-
mer-analogous transformations  polyacrylonitrile 6
PVT 6 1-MVT32-MVT copolymer (M-PVT) and
radical copolymerization of freshly distilled 1-MVT
and 2-MVT (PVT-M) in the bulk in the presence of
azobis(isobutyronitrile) (0.5 mol %) at 65oC or homo-
polymerization of 1-MVT (PMVT-1) or 2-MVT
(PMVT-2), followed by reprecipitation of the result-
ing polymers from dimethylformamide solution into
methanol. The conditions of PVT synthesis are given
Changes in the isomeric composition of the poly-
mers were monitored by IR spectroscopy (Perkin3
Elmer spectrometer, model 684) using KBr technique
(4 mg polymer per 600 mg KBr), namely, by changes
in the intensities of the bands at 1100 (characteristic
of stretching3bending vibrations of the ring in PMVT-