Influence of isomerism of difluorobenzophenone on the synthesis and properties of poly(arylene ether ketones)

Article abstract of DOI:10.1023/A:1014046521021

The influence of isomerism of difluorobenzophenone on the efficiency of polycondensation and the properties of homo-and copoly(arylene ether ketones) was studied. The latter were prepared by the reaction of 2,4'-and 4,4'-difluorobenzophenone with potassium diphenolates of bisphenol A and phenolphthalein in N,N-dimethylacetamide. A high content of an admixture of the 2,4'-isomer in 4,4'-difluorobenzophenone decreases the molecular weight of related poly(arylene ether ketones) and has no substantial effect on their glass transition temperature.

Full text of DOI:10.1023/A:1014046521021

«
S. N. Salazkin, V. V. Shaposhnikova, K. I. Donetskii, G. V. Gorshkov, I. V. Blagodatskikh,
1
208
Russian Chemical Bulletin, International Edition, Vol. 50, No. 7, pp. 1208—1213, July, 2001
Influence of isomerism of difluorobenzophenone on the synthesis
and properties of poly(arylene ether ketones)
L. V. Dubrovina, A. A. Sakunts, P. V. Petrovskii, L. I. Komarova, M. M. Genina, A. S. Tkachenko,
A. A. Askadskii, K. A. Bychko, and V. V. Kazantseva
A. N. Nesmeyanov Institute of Organoelement Chemistry, Russian Academy of Sciences,
2
8 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5085. E-mail: snsal@ineos.ac.ru
The influence of isomerism of difluorobenzophenone on the efficiency of polycondensa-
tion and the properties of homo- and copoly(arylene ether ketones) was studied. The latter
were prepared by the reaction of 2,4´- and 4,4´-difluorobenzophenone with potassium
diphenolates of bisphenol À and phenolphthalein in N,N-dimethylacetamide. A high content
of an admixture of the 2,4´-isomer in 4,4´-difluorobenzophenone decreases the molecular
weight of related poly(arylene ether ketones) and has no substantial effect on their glass
transition temperature.
Key words: 2,4´-difluorobenzophenone, 4,4´-difluorobenzophenone, isomers, potassium
diphenolate, nucleophilic substitution, polycondensation, poly(arylene ether ketones), mo-
lecular weight, glass transition temperature.
The problem of optimization of conditions for syn-
thesis and the ways of controlling the molecular weight
MW) and properties of polymers is urgent in chemistry
Results and Discussion
(
Compound 1à, prepared according to Scheme 1, was
used in the synthesis of PAEK.
of poly(arylene ether ketones) (PAEK).1
—3
It is known
that the presence of admixtures in monomers used for
polycondensation can substantially affect the results of
polycondensation and properties of the polymer ob-
tained.
This work is aimed at studying the influence of
isomerism of difluorobenzophenone on polycondensa-
tion via the mechanism of nucleophilic substitution of
aryl halide and the properties of PAEK. The problem of
isomerism of difluorobenzophenone is general regard-
less of the method of its synthesis. For example, the
The formation of 1b along with 1à was found by
HPLC. A mixture of the 4,4´- (67%) and 2,4´-isomers
(33%) was isolated from the reaction mixture. Treat-
ment by hydrolysis, filtration, washing, and crystalliza-
tion enriches the mixture in the 4,4´-isomer. Data in
Table 1 indicate a change in the ratio of two isomers
after each crystallization and also show the influence of
the isomeric composition on the melting point of 1à.
Crystallization from EtOH decreases the concentration
of the 2,4´-isomer from 12.7 to 0.3% (cf. fractions 1 and
13) after three crystallizations, and no 2,4´-isomer was
detected after final crystallization from hexane. This can
clearly be illustrated by a comparison of Figs. 1 and 2. A
high content of the 2,4´-isomer in sample 1à decreases
2
,4´-isomer can be formed not only in the synthesis of
difluorobenzene by the method described below but also
by other known methods, viz., by the reaction of
fluorobenzene with phosgene.
Scheme 1
AlCl3
H O (vapor)
2
2
F
+ CCl4
F
CCl2
F
+
F
CCl2
–2 HCl
–2 HCl
F
6
7
3
6
7
3
13 12
1
C
1
C
5
2
5
2
8
F
F
+
F
11
9
4
O
4
O
10
F
1
a
1b
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1152—1156, July, 2001.
066-5285/01/5007-1208 $25.00 © 2001 Plenum Publishing Corporation
1

The synthesis of poly(arylene ether ketones)
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 7, July, 2001
1209
Table 1. Influence of crystallization on the isomeric composition and melting point of difluorobenzophenone
Crystal-
lization
Solvent
EtOH
Analyzed
fractiona
Content by HPLC data (wt. %)
M.p.
/°Ñ
1
b
1à
Xb
I
1
2
3
4
5
6
7
8
9
12.7
70.0
6.5
66.0
1.6
53.0
1.1
37.0
0.4
30.0
0.3
9.5
0.3
4.0
—ñ
93.3
21.7
94.5
26.1
98.4
40.8
98.9
63.0
99.6
70.0
99.7
90.5
99.7
96.0
99.7
99.7
—
8.3
—
7.9
—
6.2
—
—
—
—
—
—
—
—
—
—
95.0—101.0
60.0—76.0
99.0—103.0
69.0—82.0
105.5—107.0
80.0—95.5
105.5—106.5
90.0—100.0
106.0—107.5
95.0—97.0
106.0—107.5
102.0—103.0
106.5—107.0
105.0—106.5
107.0—107.5
106.0—107.0
II
III
IV
EtOH
EtOH
1
1
1
0
1
2
Ãåêñàí
13
1
1
1
4
5
6
ñ
—
à
1
, 5, 9, and 13 are the product after the first, second, third, and fourth crystallization, respectively; 2, 6, 10,
and 14 are the mother liquor after the first, second, third, and fourth crystallization, respectively; 3, 7, 11, and
5 are the product after the first, second, third, and fourth crystallization, respectively, and washing with a
1
solvent; 4, 8, 12, and 16 are the solvent used for washing of the product after the first, second, third, and fourth
crystallization, respectively.
b
It can be assumed that 2,2´-difluorobenzophenone is the nonidentified component (X).
The admixture of 1b is << 0.3 wt.%, found qualitatively.
ñ
sharply the melting point and extends the melting in-
terval.
1
For using compound 1à obtained by Scheme 1 in
polymer synthesis, it was important to study the influ-
ence of 1b (this monomer was synthesized by the con-
densation of 2-fluorobenzoyl chloride with fluoro-
benzene) on the MW and properties of the obtained
PAEK. With the purpose for studying the influence of
the isomeric composition of difluorobenzophenone on
polycondensation, we obtained homopolymers based on
monomers 1à,b and 2à,b and copolymers at different
ratios of the starting monomers (Scheme 2).
2
3
4
5
t/min
Fig. 1. Chromatogram of nonpurified compound 1a. Eluent
methylene chloride—hexane, 3 : 1. Peak 1 corresponds to 1a,
A comparison of the IR spectra of the homopolymers
based on 1à,b and 2à in the region of 600—900 cm
–1
2
corresponds to 1b.
does not allow us to pick out a sufficiently intense and
isolated absorption band for the identification of the
ortho-substituted derivative. The type of substitution is
more pronounced in other spectral regions. For ex-
ample, the type of substitution noticeably affects the
position of the band of stretching vibrations of Ñ=Î.
For the homo-PAEK based on 1à, the maximum of the
band of stretching vibrations of Ñ=Î is observed at
1
651 cm–1, and in the spectrum of the 1b-based ho-
mopolymer it is observed at 1662 cm–1. The most
significant differences are observed in the region of
1
400—1500 cm–1. The spectrum of the homopolymer
based on 1b exhibits two rather intense bands, which do
not overlap with other bands, with maxima at 1480 and
1446 cm–1. These two bands can serve as a good
indicator for determining the ortho-substituted fragments
in copolymers. However, a comparison of the IR spec-
3
4
5
t/min
Fig. 2. Chromatogram of purified compound 1a. Eluent meth-
ylene chloride—hexane, 2 : 1.

1
210
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 7, July, 2001
Salazkin et al.
Scheme 2
K CO3
2
np F
C
O
F + n HO
R
OH + nq F
C
O
F
1
a
2a,b
1b
C
O
O
R
O
C
O
O
R
O
p
q
n
R =
C
(=),
C
(>)
O
MeMe
C
O
p/q = 0/100—100/0
tra of copolymers with different compositions with each
other and homopolymers shows the identity of the
spectra of all copolymers (when the content of frag-
ments 1b ≤ 10 mol.%) with the homopolymer contain-
ing fragment 1a. Additional studies are necessary to
reveal reasons for this fact.
The structure of the synthesized homo-PAEK based
on 1à,b and 2à was also confirmed by the data of 1
and 13Ñ NMR spectroscopy (Table 2). The 1Í NMR
spectrum of the homopolymer based on 1b and 2à has a
specific feature: the presence of a triplet of protons of
methyl groups at Ñ(8) and Ñ(9) with δ 1.61, 1.66, and
Í
Table 2. Chemical shifts and multiplicities of signals in 1Í and 13Ñ NMR spectra of homo-PAEK based on 1a
or 1b and 2a
8
2
3
CH3 11 12
17 18
24 25
2
C
2
23
1
4
10
16
19
26
O
C
O
3
1
7
2
7
6
5
CH
9
15 14
21 20
O
28
3
n
Homo-PAEK
δ
1Í
13Ñ
1
a + 2a
1.72 (s, 6 Í, Í(8), H(9));
.00 (d, 4 Í, Í(2), H(6),
H(12), H(14)) ; 7.03 (d, 4 Í,
30.68 (C(8), C(9)); 41.98 (C(7));
7
114.68 (Ñ(17), C(21), C(25), C(27));
118.37 (Ñ(2), C(6), C(12), C(14));
127.39 (Ñ(18), C(20), C(24), C(28));
131.65 (Ñ(3), C(5), C(11), C(15));
131.77 (Ñ(19), C(23)); 146.36 (Ñ(4), C(10));
153.07 (Ñ(16), C(26)); 161.04 (C(1), C(13));
a
a
Í(17), H(21), H(25), H(27)) ;
.28 (d, 4 Í, Í(3), H(5),
7
a
H(11), H(15)) ; 7.79 (d, 4 Í,
Í(18), H(20), H(24), H(28))a
1
93.69 (C(22))
1
b + 2a
1.61, 1.66, 1.71 (t, 6 Í, Í(8), H(9));
7
6
30.63 (Ñ(8), C(9)); 41.70, 41.81, 41.95 (C(7));
116.78 (Ñ(17), C(21)); 118.00 (C(27));
118.51 (Ñ(2), C(6), C(12), C(14));
.82 (d, 2 Í, Í(18), H(20))b;
.79—7.60 (ì)
1
1
1
1
19.28 (Ñ(18), C(20)); 123.00 (C(25));127.71 (C(23));
28.05 (Ñ(3), C(5), C(11), C(15)); 129.60 (C(24));
33.00 (C(26)); 152.91 (Ñ(4), C(10)); 154.36 (C(28));
54.60 (C(16)); 154.60 (C(16)); 194.03 (C(22))
a 3J
= 8.3 Hz.
H,H
b 3JH,H = 7.6 Hz.

The synthesis of poly(arylene ether ketones)
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 7, July, 2001
1211
1
.71 and relative integral intensities of 1.2, 2.1, and 1.0,
A comparison of the MW of 2a-based PAEK and
difluorobenzophenone isomers 1a and 1b, obtained un-
respectively. In the 13Ñ NMR spectrum of the ho-
mopolymer based on 1b and 2à, the Ñ(8) and Ñ(9)
atoms of the methyl groups appear as a singlet signal at
δ 30.63 (∆ν = 0.09 ppm). By contrast, the signal from
Ñ(7) is observed as a triplet with δ 41.70, 41.81, and
der similar conditions and presented in Table 3, indi-
—
cates a more than tenfold decrease in Mw when the
4,4´-isomer is replaced by the 2,4´-isomer (cf., the data
for the 1à-based homo-PAEK obtained without MW
regulation and for the 1b-based homo-PAEK). Similarly,
4
1.95 and relative integral intensities of 1.4, 2.3, and
1
.0. The presence of this triplet splitting of the corre-
the PAEK based on 2b and 1a,b differ strongly by ηred.
sponding signals in the Í and 13Ñ NMR spectra is due
to the presence in the macromolecule of fragments 2à
with different types of substitution (o,o´, o,p´, p,î´, and
p,p´) in two adjacent phenoxy groups with ratios close
to the statistical one.
1
The decrease in MW is a result of a considerable
decrease in the reactivity of the F atom in the
ortho-position to the activating group as compared to
the para-position due to steric hindrances in the reac-
tion with a sufficiently bulky nucleophile. The resulting
MW is determined (at the rigidly equivalent ratio of
monomers) by the ratio of the rates of the main chain
growth reaction and side reactions, which restrict the
chain growth. Probably, the MW restriction can be due
to the fact that, in this case, the competing reaction
with a stronger base, potassium hydroxide, and macro-
cyclization is most favorable. A comparison of the rela-
tive reactivities of the functional groups of molecules
1a,b in the reaction with 2a showed that in the symmet-
ric monomer 1a the reactivity of the second functional
group decreases fourfold after the transformation of the
first group into the ether bond. Meanwhile, in the case
of the nonsymmetric monomer 1b, the reactivity differs
already by at least ten times (this problem will be
considered in detail elsewhere). Thus, the halogen atom
A study of the dynamics of changing MW of the
homo-PAEK based on 1b and 2a,b showed that a lower
activity of 1b compared to 1a, which is illustrated by a
much slower increase in the reduced viscosity (ηred) of
polymers in time compared to the homo-PAEK based
on 1a and 2a,b.1—3 The ηred values of the homo-PAEK
based on 1b and 2a were 0.06, 0.18, and 0.20 dL g
after 3, 7, and 50 h, respectively, and those for the
homo-PAEK based on 1b and 2b were 0.10, 0.18, and
0
5
–
1
.13 dL g–1. This indicates that a sharp increase (to
0 h) in the polycondensation duration is not efficient.
The decrease in ηred of the homo-PAEK based on 2b
after 50-h synthesis is due, most likely, to destructive
processes, which is indirectly indicated by strong dark-
ening of the reaction mixture.
—
Table 3. Influence of the chemical structure of homo- and co-PAEK based on 1à,b and 2à,b on ηred, M , Ò , and mechanical
w
g
properties of the films
—
M
—
E •10
•10–3
Òga
—
σ
—
σ
—
σ
–3
—
ε
0
—
ε
Bis-
Molar ratio
1à : 1b
ηred
/dL g
w
0
int
–
1
phenol
/°Ñ
MPa
%
b
—c
61
2
à
0 : 100
0 : 10
0.20
0.54
15.8
140
165
—
—
—
—
—
d
9
50
5d
.6
b
9
79
—
1.7
6.4
236
4
9
9
9
7 : 3
8 : 2
9 : 1
0.68
0.65
0.95
0.30
—
—
—
145
145
150
150
160
165
160
—
210
210
210
225
245
71
74
69
70
70
66
—
83
95
95
—
89
84
101
87
105
—
1.9
1.8
2.0
—
1.6
1.6
1.9
—
2.4
2.0
1.9
3.0
2.0
5.5
6.0
6.5
—
5.2
4.6
5.3
—
7.0
8.0
—
7.0
6.8
110
127
79
131
109
—
—
—
195
—
140
135
—
e
e
e
d
c
1
00 : 0
10
22
39
—
—
d
0
0
2
.53
.75
.40
70
62
70
214
240
240
—
40
57
8
15
172
d
d
230
—
—
—
—
c
2
b
0 : 100
0 : 10
7 : 3
8 : 2
9 : 1
0.13
1.00
1.02
1.07
1.28
5.2
—
9
104
101
—
101
100
9
9
9
—
—
143
200
1
00 : 0
a
The temperature corresponding to the interception point of tangents to the branches of the thermomechanical curve in the region
of flow beginning was taken as Ò .
g
—
M
b
was determined using the light scattering method by T. P. Bragina at the Laboratory of Physical Chemistry of Polymers
w
(
Institute of Organoelement Compounds, RAS).
c
The polymer forms brittle films, which are spilled on the support during molding and drying.
—
M
d
e
was determined by GPC using the calibration for PAEK based on 2à.
w
The samples of homo-PAEK were obtained using the monofunctional reagent 4-fluorobenzophenone as a regulator of MW.

1
212
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 7, July, 2001
Salazkin et al.
in the ortho-position to the Ñ=Î group in molecule 1b
is more than 2.5-fold more active than the second
halogen atom in the para-position in molecule 1a. It
follows from this that 1a containing almost no
The molecular weight distribution and mean molecular
weight of polymers were determined by GPC using a previously
1
,3
described procedure.
sured by the light scattering method on
The mean molecular weight was mea-
Fica photo-
a
goniodiffusimeter at 25 °Ñ and λ = 546 nm in the vertically
polarized light using the double extrapolation according to
2
,4´-isomer should be used for the synthesis of high-
molecular PAEK.
Simm. The instrument was calibrated by benzene.
A comparison of the glass transition temperatures
1Í and 13Ñ NMR spectra for compounds 1à,b and PAEK
(
Ò ) and some physicomechanical properties of the
were recorded on an Bruker ÀÌÕ-400 instrument (400.13 and
100.61 MHz, respectively) for solutions in CDCl3 using Me4Si
as the internal standard. Signals in the Í and Ñ NMR
spectra were assigned according to calculated data obtained by
the additive scheme. 19F NMR spectra for 1à,b were recorded
on a Bruker WP-200-SY spectrometer (188.31 MHz) for solu-
g
—
films (the forced elasticity limit (σ ), strength at the
rupture moment calculated per initial cross section of
the sample (σ), deformation at which the forced elastic-
0
1
13
—
—
ity limit appears (ε ), relative elongation upon rupture
0
—
(
ε ), strength at the rupture moment calculated per true
tions in CDCl3 using ÑF COOH as the external standard.
3
—
cross-section of the sample (σ ), and high-elasticity
t
IR spectra were recorded on a Perkin—Elmer-457 spec-
trometer.
The reduced viscosity (ηred) of PAEK solutions was mea-
sured in CHCl3 (at a concentration of 0.5 g of the polymer per
—
modules (E )) of the synthesized amorphous homo- and
co-PAEK shows that the presence of fragments 1b in
them has no substantial effect on the studied properties
of these polymers compared to the 1a-based ho-
mopolymers.
1
00 mL of the solvent) at 25 °Ñ.
Thermochemical tests of polymers were carried out accord-
ing to a previously described procedure.4
The conformational properties of the macromol-
ecules containing fragments 1a and 1b differ most sig-
nificantly. This is expressed, first, in a decrease in ηred
of polymer solutions at the same MW (see Table 3);
second, in underestimated Mw values of the 1b-based
polymers determined by GPC and calculated using the
calibration for the 1a-based polymers (see Table 3)
compared to the absolute Mw values measured by the
light scattering method; third, in an increase in the
content of cyclic oligomers in reaction mixtures (cyclic
dimer, from 2.6 to 3.8% and trimer, from 1.3 to 1.8%).
The results of the detailed study of cycle formation in
these PAEK will be published elsewhere. The data pre-
sented in this work indicate a more closed conformation
of the chains of the 1a-based PAEK macromolecules,
which should be expected from a comparison of the
chemical structure of PAEK based on 1a and 1b. It can
be assumed that a higher affinity to cycle formation
during the synthesis of the 1b-based polymers and a
more closed conformation of the chains of the PAEK
macromolecule prevent, along with the low activity of
the î-halogen atom in 1b, the preparation of PAEK
with higher MW.
4
,4´-Difluorobenzophenone (1à) was synthesized by a pro-
cedure5 modified by us, its m.p. was 107.5—108.0 °Ñ after
3
sublimation (cf. Ref. 6: m.p. 107.5—108.0 °Ñ). The isomeric
purity was monitored by HPLC (content of 1b << 0.3 wt.%).
IR, ν/cm–1: 1646 (C=O). 1H NMR (CDCl3), δ: 7.10 (dd, 4 Í,
—
Í(4), H(6), 3J
= 8.8 Hz, 3JF,Í = 8.8 Hz); 7.76 (dd, 4 Í,
Í,Í
Í(3), H(7), 3J
= 8.8 Hz, 3
J
= 5.2 Hz). 13Ñ NMR
F,Í
Í,Í
2
—
(CDCl ), δ: 115.26 (Ñ(4), C(6), JÑ,F = 21.7 Hz); 132.24
3
(
1
Ñ(3), C(7), JÑ,F = 9.2 Hz); 133.41 (Ñ(2), 4JÑ,F = 2.9 Hz);
3
66.35 (Ñ(5), 1JÑ,F = 254.6 Hz); 193.43 (Ñ(1)). 19F NMR
(
CDCl ), δ: –28.03 (s, 1 F, Ñ(5)F) (for the numeration of
3
atoms, see Scheme 1).
2,4´-Difluorobenzophenone (1b) was synthesized by the re-
action of 2-fluorobenzoyl chloride with fluorobenzene in the
3
presence of AlCl3 and FeCl3 by a procedure modified by us,
m.p. 22.0—22.5 °Ñ (cf. Ref. 7: m.p. 22.8—23.6 °Ñ). IR, ν/cm–1:
1
1
3
664 (C=O). H NMR (CDCl ), δ: 7.13 (d, 2 Í, Í(4), H(6),
3
3
JÍ,Í = 8.8 Hz, JF,Í = 8.8 Hz); 7.21 (t, 1 Í, Í(10),
3J
= 8.8 Hz, 3J
= 8.8 Hz); 7.26 (t, 1 Í, Í(12),
F,Í
= 8.8 Hz); 7.53 (m, 2 Í, Í(11), H(13)); 7.88 (dd, 2 Í,
= 5.6 Hz). 13Ñ NMR
Í,Í
3J
Í,Í
Í(3), H(7), 3JÍ,Í = 8.8 Hz, 3
J
F,Í
2
(CDCl3), δ: 115.37 (Ñ(4), C(6), JC,F = 22.1 Hz); 115.99
2
4
(
(
(
1
1
Ñ(10), J
= 21.3 Hz); 124.15 (Ñ(12), J
= 3.6 Hz); 126.44
= 2.8 Hz); 132.19
C,F
C,F
Ñ(8), 2JC,F = 14.9 Hz); 130.57 (Ñ(13), 3J
C,F
Ñ(3), C(7), 3JC,F = 9.2 Hz); 132.97 (Ñ(11), 3JC,F = 8.0 Hz);
33.46 (Ñ(2), 4J
= 2.4 Hz); 159.62 (Ñ(9), 1JC,F = 252.2 Hz);
C,F
65.65 (Ñ(5), 1JC,F = 255.8 Hz); 191.50 (Ñ(1)). 19F NMR
Experimental
(
CDCl ), δ: –33.34 (s, 1 F, Ñ(9)F); –26.62 (s, 1 F, Ñ(5)F) (for
3
the numeration of atoms, see Scheme 1).
An admixture of 1b in 1à was analyzed by normal-phase
HPLC using a Milikhrom-1 instrument with a spectrophoto-
metric detector on a microcolumn (5 cm ½ 2 mm) packed with
the Silasorb-600 sorbent in a mixture of methylene chlo-
ride—hexane (3 : 1 or 2 : 1). The sample volume was 5—10 µL,
and the concentration was 1—2 mg mL– . The method allows
the separation of the peaks of 1à and 1b to the basic line with
the resolution coefficient R > 1 and the quantitative determina-
tion of the concentration of each component. The peaks were
identified by the specially synthesized pure isomers, and the
response coefficients were calibrated at different λ. The average
reproducibility of the results of determination of the content of
2,2-Bis(4´-hydroxyphenyl)propane (2à) (trade mark A, Ufa
PO Khimprom, Russia) was additionally purified according to a
previously described procedure.8
3,3-Bis(4´-hydroxyphenyl) phthalide (phenolphthalein) (2b)
("farmakopeinyi" trade mark, Moscow Alkaloid Plant) with
m.p. 260.5—261.0 °C was dried for 4 h at 120 °C.
1
Synthesis of PAEK. Argon was passed through a four-
necked flask with a stirrer, a pipe for argon supply, and a
system for azeotropic water distillation. Then compound 1à or
1b (21.8 g, 0.1 mol), compound 2a (22.8 g, 0.1 mol), prelimi-
narily powdered and calcined Ê ÑÎ (18 g, 0.13 mol), N,N-di-
2
3
methylacetamide (200 mL), and PhCl (100 mL) were loaded
into the flask. The temperature of the oil bath was gradually
(within ∼0.5 h) increased to 185 °Ñ. The duration of the
synthesis after the completion of the azeotropic water distilla-
1
b by two measurements in a mixture was 0.2%. The procedure
allowed the measurement of the concentration of 1b to 0.3%
and detection of admixtures up to <0.3%.

The synthesis of poly(arylene ether ketones)
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 7, July, 2001
1213
tion off was 10 h (in the case of 1b, 50 h). After the end of the
synthesis, the reaction mixture was cooled, CHCl3 was added,
and the obtained solution was filtered to remove the salt and
multiply washed with water. The polymer isolated as a film by
the evaporation of the solvent was dried with a gradual increase
in the temperature from 60 to 140 °Ñ for 18 h and then at
50 °Ñ for 25 h. The yield of PAEK was 40.0 g (98.5%).
When the dynamics of changing ηred was studied in time,
the reaction mixture was sampled at time intervals.
Afonicheva, N. A. Svetlova, A. S. Kogan, and A. S.
Tkachenko, Vysokomol. Soedin., 1999, À41, 217 [Russ. Polym.
Sci. USSR, 1999, À41 (Engl. Transl.)].
3. V. V. Shaposhnikova, Ph. D. (Chem.) Thesis, Institute of
Organoelement Compounds, Russian Academy of Sciences,
Moscow, 1993, 141 pp. (in Russian).
4. B. L. Tsetlin, V. I. Gavrilov, N. A. Velikovskaya, and V. V.
Kochkin, Zavod. Lab. [Plant Laboratory], 1956, 22, 352 (in
Russian).
1
5
. K. A. Chernyakovskaya, G. S. Mironov, M. I. Farberov,
I. M. Tyuleneva, and N. A. Rovnyagina, Uch. zap.
Yaroslavskogo tekhnologicheskogo in-ta [Scientific Recordings
of the Yaroslavl Technological Institute], 1970, 13, 92 (in
Russian).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 98-03-
3
3411).
6
7
8
. R. D. Dunlop and J. H. Gardner, J. Am. Chem. Soc., 1933,
5
5, 1665.
. H. L. Bradlow and C. A. van der Werf, J. Am. Chem. Soc.,
947, 69, 662.
References
1
. S. N. Salazkin, A. I. Kalachev, V. V. Korshak, and S. V.
Vinogradova, Deposited to VINITI 14.04.75, No. 1064-75,
Moscow, 1975, 22 pp.; RZhKhim, 1975, 15Zh198 (in
Russian).
1
2
. V. V. Shaposhnikova, S. N. Salazkin, V. A. Sergeev, I. V.
Blagodatskikh, L. V. Dubrovina, A. A. Sakunts, and S.-S. A.
Pavlova, Izv. Akad. Nauk, Ser. Khim., 1996, 2526 [Russ.
Chem. Bull., 1996, 45, 2397 (Engl. Transl.)].
. V. V. Shaposhnikova, S. N. Salazkin, K. I. Donetskii, G. V.
Gorshkov, A. A. Askadskii, K. A. Bychko, V. V. Kazantseva,
A. V. Samoryadov, A. P. Krasnov, B. S. Lioznov, O. V.
Received August 18, 2000;
in revised form March 12, 2001