ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 10, pp. 1717!1720. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + I.A. Opeida, M.A. Kompanets, O.V. Kushch, A.G. Matvienko, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80,
No. 10, pp. 1688!1691.
AND POLYMERIC MATERIALS
N-Hydroxyphthalimide-Initiated Radical Polymerization
of Vinyl Monomers
I. A. Opeida, M. A. Kompanets, O. V. Kushch, and A. G. Matvienko
Litvinenko Institute of Physicoorganic Chemistry and Coal Chemistry, National Academy of Sciences
of Ukraine, Donetsk, Ukraine
Received May 2, 2007
Abstract-The initiating ability of N-hydroxyphthalimide in polymerization of methyl methacrylate and
acrylonitrile was examined. For the polymerization of methyl methacrylate, the initial polymerization rates
and activation energies were determined, and the dependences of the polymerization rates on the initiator
and monomer concentrations were evaluated. An initiation mechanism was suggested.
In recent years, much attention has been received
by N-hydroxyphthalimide (HPI), a catalyst for oxida-
tion of organic substrates by molecular oxygen at
C3H bonds, with a view to preparation of valuable
oxygen-containing products . In such processes,
HPI acts as a radical catalyst of the chain propagation
stage in which the N-oxyl radical of phthalimide,
formed from the HPI molecule, exhibits high selec-
tivity in abstraction of a hydrogen atom . An ex-
amination of how it influences the oxidation of unsat-
urated compounds showed that N-hydroxyphthalimide
is also efficient in initiation of radical polymerization
of methyl methacrylate (MMA) and acrylonitrile (AN),
i.e., it can enter into addition reactions at double
bonds. Sato et al.  also mentioned the initiating ef-
fect of HPI in polymerization of vinyl compounds.
We examine here the kinetic relationships in
N-hydroxyphthalimide-initiated radical-chain poly-
N-Hydroxyphthalimide available from Fluka was
used without additional purification. Benzoyl peroxide
(BP) and azobis(isobutyronitrile) (AIBN) were recrys-
tallized twice from ethanol. Acetonitrile was purified
by the standard technique . Methyl methacrylate
was thrice washed with 10315% aqueous alkali solu-
tion to exhaustively remove the inhibitor. Then it
was thrice washed with distilled water, dried over
anhydrous calcium chloride, and distilled in a ni-
trogen atmosphere at reduced pressure to isolate
the (22 + 0.2)oC/25 mm Hg fraction. We used freshly
distilled methyl methacrylate.
Acrylonitrile was washed successively with dilute
sulfuric acid, a 5% Na
solution, and water,
whereupon it was dried over molecular sieves and
distilled in a nitrogen stream.
The polymerization kinetics for methyl methacry-
late and acrylonitrile was examined dilatometrically.
The monomer content of the reaction mixture was
25 vol %. Polymerization of MMA and AN in
the presence of HPI, BP, and AIBN was carried out
in an acetonitrile solution at 339 K. The concentra-
tions of AIBN and BP were 5 0 10
and 1 0 10
respectively, and that of HPI, 1 0 10
31 0 10
The polymerization rates were estimated from
the slope of the kinetic curve in the initial stage of
the reaction (up to 5% conversion of the monomer),
when it is virtually linear.
The table lists the initial rates of polymerization in
acetonitrile for methyl methacrylate and acrylonitrile
in the presence of BP, AIBN, and HPI, as well as
of PB3HPI and AIBN3HPI systems.
It is seen that addition of N-hydroxyphthalimide to
the monomer containing initiator (BP or AIBN) ac-
celerates the polymerization of MMA. Importantly,
HPI can by itself initiate the polymerization in
the absence of classical initiators in the system. It
should be noted that, under the actual conditions,