Direct synthesis of a three-dimensional cross-linked tris(4-vinylbenzyl) phosphine oxide polymer from 4-vinylbenzyl chloride and red phosphorus

Full text of DOI:10.1134/S0012500808010023

ISSN 0012-5008, Doklady Chemistry, 2008, Vol. 418, Part 1, pp. 5–7. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © S.F. Malysheva, V.A. Kuimov, B.G. Sukhov, N.K. Gusarova, B.A. Trofimov, 2008, published in Doklady Akademii Nauk, 2008, Vol. 418, No. 1,
pp. 56–58.
CHEMISTRY
Direct Synthesis of a Three-Dimensional Cross-Linked
Tris(4-vinylbenzyl)phosphine Oxide Polymer
from 4-Vinylbenzyl Chloride and Red Phosphorus
S. F. Malysheva, V. A. Kuimov, B. G. Sukhov, N. K. Gusarova, and Academician B. A. Trofimov
Received July 12, 2007
DOI: 10.1134/S0012500808010023
Polymers containing benzylphosphine oxide frag- rus-containing polymers are also successfully used as
ments are efficient sorbents for uranium [1]. They are environmentally friendly fire retardants for decreasing
prepared by successive treatment of 4-vinylbenzyl the combustibility of polymeric materials [5–7].
chloride–divinylbenzene (10%) cross-linked copoly-
The purpose of this study is to develop a new indus-
mer with phosphorus iodide (P2I4), alkyl iodide, and the
trially feasible method for the synthesis of poly(4-
Na2SO3–NaOH system [1]. Polymers of this type with
vinylbenzyl)phosphine oxide by direct phosphorylation
a benzylphosphine group, for example, poly(4-vinyl-
of 4-vinylbenzyl chloride with red phosphorus.
benzyldiarylphosphines), have been extensively stud-
ied in recent years as effective ligands for new-genera-
The reaction easily proceeds in the KOH–dioxane–
tion metal complex catalysts [2–4]. These ligands are water–phase transfer catalyst system to give initially
synthesized by a two-step procedure including the reac- tris(4-vinylbenzyl)phosphine oxide I, which then poly-
tion of polystyrene with chlorodimethyl ether followed merizes on gentle heating (55–60°C, 0.5 h) to give
by treatment of the intermediate poly(4-vinylbenzyl cross-linked polymer II in 52% yield (calculated rela-
chloride) with lithium diaryl phosphides [2]. Phospho- tive to the initial 4-vinylbenzyl chloride) (Scheme 1).
P
Cl
KOH, H2O
Pn +
O
I
P
55–60°C
O
II
Scheme 1.
Favorsky Institute of Chemistry, Siberian Branch,
Russian Academy of Sciences, ul. Favorskogo 1, Irkutsk, 664033 Russia
5

6
MALYSHEVA et al.
Phosphorylation starts, apparently, with cleavage of stirred for an additional 1.5 h at 45–50°C, diluted with
the polymeric red phosphorus molecule, induced by a water, and extracted with benzene. The extract was
strong base, to give nanosized anionic clusters with washed with water and dried with potassium carbonate.
enhanced nucleophilicity (Scheme 2) [8–10].
Benzene was distilled off at a reduced pressure to give
0.81 g of the product. According to IR and 1H and 31P
NMR data, the product was phosphine oxide I (purity
~95%), which was identified based on an authentic
sample [11].
Pm–
KOH
+
Pk OH
Pn
Monomer I was heated at 55–60°C for 0.5 h under
argon, washed successively with benzene and ether,
and dried in vacuum to give 0.76 g of nonmelting poly-
mer II (yield 50%).
KOH
–H2O
Pk–
O
Pk OH
Scheme 2.
For C27H27OP anal. calcd. (%): C, 81.38; H, 6.83;
P, 7.77.
Polymer II thus formed is insoluble in organic sol-
vents and water. Its IR spectrum exhibits strong absorp-
tion bands at 1130 (ν P=O), 1500, and 1600 cm–1 (ben-
zene ring stretches) and weak absorption bands at 3015
and 3040 cm–1 (CH stretches of the disubstituted ben-
zene ring and the residual styrene fragments).
Found (%): C, 80.68; H, 6.97; P, 8.00.
The IR spectrum was recorded on a Specord IR-75
spectrophotometer (KBr). The 1H and 31P NMR spectra
were recorded on a Bruker DPX 400 spectrometer (400
and 161.98 MHz, respectively) with HMDS as the
internal reference and CDCl3 as the solvent. All exper-
imental stages were carried out under argon.
Polymerization of monomer I should inevitably
involve cyclopolymerization to give cyclic structures,
shown in Scheme 3, and large macrocycles with nano-
sized cavities within a three-dimensional polymer net-
work.
Thus, a fundamentally new approach to the industri-
ally feasible synthesis of cross-linked organophospho-
rus polymers with phosphine oxide functions was
developed. These polymers are promising as sorbents
for uranium and transuranium elements and ligands for
metal complex catalysts and fire retardants.
The addition of polymer II (0.1–1.0 wt %) to poly-
vinyl chloride plastisols decreases their flammability
and combustibility [7].
P
O
ACKNOWLEDGMENTS
This work was supported by the Russian Founda-
tion for Basic Research (project no. 05–03–32859)
and the Siberian Branch of the RAS (integration
project no. 32).
Scheme 3.
The polymers thus formed should also contain unre-
acted styryl groups capable of further polymerization
and functionalization (e.g., through the addition of var-
ious reagents to the double bond). The ratio of the
cross-linking to cyclopolymerization processes and the
number of pendant styryl groups should be dictated by
the polymerization conditions (temperature, heating
time, catalysis), which opens up extensive opportuni-
ties for the control of the properties of the resulting
polymers.
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