Rearrangement of polyarylene benzimidates into poly(N-arylenebenzamides)

Article abstract of DOI:10.1134/S1070427206030190

The transformation of polyarylene benzimidates prepared by polycondensation of bisphenols with benzimidoyl chlorides in N-methyl-2-pyrrolidone into poly(N-arylenebenzamides) was studied. Pleiades Publishing, Inc., 2006.

Full text of DOI:10.1134/S1070427206030190

ISSN 1070-4272. Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 3, pp. 430 432. Pleiades Publishing, Inc., 2006.
Original Russian Text V.F. Burdukovskii, D.M. Mognonov, S.O. Botoeva, Zh.P. Mazurevskaya, 2006, published in Zhurnal Prikladnoi Khimii, 2006,
Vol. 79, No. 3, pp. 437 439.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Rearrangement of Polyarylene Benzimidates
into Poly(N-arylenebenzamides)
V. F. Burdukovskii, D. M. Mognonov, S. O. Botoeva, and Zh. P. Mazurevskaya
Baikal Institute of Nature Management, Siberian Division, Russian Academy of Sciences,
Ulan-Ude, Buryatia, Russia
Received June 8, 2005
Abstract The transformation of polyarylene benzimidates prepared by polycondensation of bisphenols with
benzimidoyl chlorides in N-methyl-2-pyrrolidone into poly(N-arylenebenzamides) was studied.
DOI: 10.1134/S1070427206030190
Polyarylene benzimidates (PBIs) prepared by poly-
condensation of imidoyl chlorides derived from aro-
matic mono- and dicarboxylic acids with bisphenols
[1] exhibit high heat resistance and large interval bet-
ween the decomposition onset and softening points.
Specific features of the imidate bond and available
data on its reactivity [2] allowed us to suggest the
possibility of the following rearrangement in the poly-
mer chain:
IIj, X = (p-C H ) CH , Y = m-C H ; IIk, X = (p-
6 4 2 2 6 4
C H ) CH , Y = (p-C H ) CMe ; IIl, X = (p-
6
4 2
2
6
4 2
2
C H ) CH , Y = (p-C H ) SO .
6
4 2
2
6
4 2
2
Initially we studied the rearrangement of a model
compound, phenyl N-phenylbenzimidate III, into
N, N-diphenylbenzamide IV, known as Chapman
rearrangement [3]:
O
Ph
.
Ph
C N
2
C
Ph
N Ph
III
O
Y
O
Ph
C
N
N X
C
IV
Ph
Ph
n
Ia Im
We found that heating of III at 250 C for 13 h
leads to its complete transformation into IV. The
13
,
structure of the product was proved by IR and
C
Y
C Ph
N
N X
NMR spectroscopy. The IR spectrum of IV contains
Ph
C
n
1
a C=O absorption band at 1657 cm , whereas the
O
O
1
13
C O band at 1210 cm is absent. In the C NMR
spectrum of IV, a carbonyl carbon signal appears at
170.53 ppm.
IIa IIl
Ia, X = p-C H , Y = m-C H ; Ib, X = p-C H , Y =
(p-C H ) CMe ; Ic, X = p-C H , Y = (p-C H ) SO ;
Id, X = m-C H , Y = p-C H ; Ie, X = Y = m-C H ;
If, X = m-C H , Y = (p-C H ) CMe ; Ig, X = m-
C H , Y = (p-C H ) SO ; Ih, X = (p-C H ) O, Y =
p-C H ; Ii, X = (p-C H ) O, Y = m-C H ; Ij, X =
(p-C H ) O, Y = (p-C H ) SO ; Ik, X = (p-C H )
6
4
6
4
6 4
6
4 2
2
6
4
6
4 2
2
Having obtained the positive result in the model
reaction, we examined the possibility of the similar
rearrangement in PBIs.
6
4
6
4
6 4
6
4
6
4 2
2
6
4
6
4 2
2
6 4 2
The possibility of thermal rearrangement of the
polymers was checked with Ie as example (Fig. 1).
The first evidences of the transformation in the melt
appear in 3 h, after which the reaction accelerates and
is complete in 18 h at 86% conversion. The rearrange-
ment in a film and in the glassy state involves a long
induction period and therefore takes more than 30 h.
The rearrangement of Ie, according to viscosity meas-
urements, is not accompanied by significant changes
in the molecular weight. The conversion was esti-
6
4
6
4 2
6 4
6
4 2
6
4 2
2
6 4 2
CH , Y = p-C H ; Il, X = (p-C H ) CH , Y = m-
2
6
4
6
4 2
2
C H ; Im, X = (p-C H ) CH , Y = (p-C H ) CMe ;
6
4
6
4 2
2
6
4 2
2
IIa, X = Y = m-C H ; IIb, X = p-C H , Y = (p-
C H ) CMe ; IIc, X = p-C H , Y = (p-C H ) SO ;
IId, X = m-C H , Y = p-C H ; IIe, X = Y = m-C H ;
IIf, X = m-C H , Y = (p-C H ) CMe ; IIg, X = (p-
6
4
6 4
6
4 2
2
6
4
6
4 2
2
6
4
6
4
6 4
6
4
6
4 2
2
C H ) O, Y = m-C H ; IIh, X = (p-C H ) O, Y =
6
4 2
6
4
6 4 2
(p-C H ) SO ; IIi, X = (p-C H ) CH , Y = p-C H ;
6
4 2
2
6
4 2
2
6 4
430

REARRANGEMENT OF POLYARYLENE BENZIMIDATES
431
mated from the IR spectra (absorption of the imido
ester bond).
, %
Figure 1 shows the conversion curves of If in nitro-
benzene (NB) and diphenyl ether (DPE). The behavior
of If in these solvents was different. In NB, com-
pound If dissolved immediately without swelling,
whereas in DPE the dissolution occurred only on heat-
ing above 150 C. Nevertheless, at equal other condi-
tions, the rearrangement in DPE was faster.
We found that the molecular weight of PBI did not
noticeably affect the kinetic parameters of the reaction.
Our results show that the rearrangement of PBIs
into poly(N-arylenebenzamides) (PBAs) occurred
considerably more readily in the melt and in DPE at
240 C. The conditions for preparing some PBAs are
given in Table 1.
, h
in (1) melt,
PBI conversion
as a function of time
(2) glassy state, (3) film, (4) DPE at 240 C, (5) DPE at
200 C, and (6) NB at 200 C.
Dynamic thermogravimetric analysis was per-
formed with a Q-1000 derivatograph in air at a heat-
For more flexible PBIs Ie, If, Il, and Im, the trans-
formation occurs to a greater extent in DPE, and for
more rigid PBIs, in the melt.
1
ing rate of 5 deg min , with Al O as reference.
2
3
The thermomechanical analysis was performed with
a Tsetlin device at a constant load of 0.08 MPa and
The structures of PBAs were confirmed by IR
spectroscopy: The C=N absorption band in PBIs at
1
a heating rate of 100 deg h .
1
1
1658 cm shifted to 1672 cm , and the C O band
1
Film materials were obtained by casting an 18 20%
solution of a polymer in DMF onto a glass support.
Physicomechanical tests of film samples were per-
formed according to GOST (State Standard) 14236
81 (COMECON Standard 1490 79), and those of
press materials, according to GOSTs 4647 80 and
4648 71.
at 1220 cm virtually disappeared. The most con-
vincing proof is furnished by C NMR spectroscopy:
13
In the spectra of PBAs, a signal of the carbonyl car-
bon atom appears at 174.7 ppm.
The PBAs obtained, like the starting PBIs, are
soluble in DMF, N, N-dimethylacetamide, DMSO,
m-cresol, and pyridine, but, in contrast to the starting
polymers, dissolve in chloroform only on heating.
Phenyl N-phenylbenzimidate. A flask equipped
with tubes for argon inlet and outlet was charged with
The glass transition point of the polymers changes
insignificantly upon PBI
275 318 to 210 252 C, respectively. The PBAs pre-
pared significantly surpass the PIDs in the heat resis-
tance: The 10% weight loss (TGA in air, 5 deg min )
is observed at 454 487 C (for the starting PIDs, at
360 415 C).
PBA rearrangement: from
Table 1. Conditions for the rearrangement of PBIs and
conversions
1
In melt
, h
In solution
PBI
T,
C
, %
, h
, %
The PBAs obtained exhibit good film-forming
properties; the physicomechanical characteristics of
the films are given in Table 2. The properties of the
press materials prepared by pressing PBA powders at
70 75 MPa/250 350 C are also given in Table 2.
Ia
340
17
17
16
17
18
16
16
16
16
17
17
17
17
89.7
88.3
90.2
89.1
86.3
89.6
92.0
87.4
90.5
91.3
86.7
90.8
92.2
14
14
14
13
14
11
13
12
11
12
13
11
10
79.2
87.1
78.8
87.9
89.4
92.8
89.6
80.2
84.5
90.3
80.5
94.0
97.8
Ib
Ic
Id
Ie
If
Ig
Ih
Ii
290
320
350
330
260
290
340
340
300
320
290
250
EXPERIMENTAL
The IR spectra were recorded on Specord IR-75
Ij
Ik
Il
1
and UR-20 spectrophotometers (4000 400 cm ) in
13
KBr. The C NMR spectra were taken on a Varian
1
VXR-500S spectrometer (400.0 MHz for H) in
Im
DMSO-d , internal reference TMS.
6
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 79 No. 3 2006

432
BURDUKOVSKII et al.
Table 2. Physicomechanical properties of PBA films and
press materials*
with tubes for argon inlet and outlet. A mixture of
0.01 mol of bisphenol with N-methyl-2-pyrrolidone
was added while purging with argon, and the mixture
was homogenized. Then 0.02 mol of triethylamine
and 0.01 mol of appropriate imidoyl chloride were
added with vigorous stirring. The homogenized reac-
tion mixture was heated to 170 180 C for 17 18 h,
after which the product was precipitated by pouring
the mixture into 2% aqueous ammonia, filtered off,
washed with a 1% solution of sodium bisulfite in
water and with water, and dried in a vacuum at 60
70 C to constant weight.
Films
t, MPa
Press materials
PBA
b, %
t, MPa a, MPa
IIa
60.7
39.2
3.0
4.6
60.4
8.2
IIb
IIc
IId
IIe
IIf
IIg
IIh
IIi
58.8
59.2
57.5
6.9
6.6
6.8
55.6
40.8
3.8
4.9
62.6
60.7
7.3
8.4
Poly(N-arylenebenzamides) were prepared by
rearrangement of the corresponding PBIs under Ar in
the melt and in DPE (Table 1).
42.6
5.5
IIj
IIk
IIl
41.8
39.1
4.8
5.0
59.1
7.1
CONCLUSION
* ( ) Breaking tensile stress, ( ) relative break elongation, and
(a) specific impact resilience.
t
b
Film-forming poly(N-arylenebenzamides) were pre-
pared by rearrangement of polyarylene benzimidates
in the melt and in diphenyl ether at 240 C. The poly-
mers obtained exhibit good solubility, high resistance
to thermal oxidative degradation, and relatively low
softening points.
250 ml of absolute ethanol and 0.3 mol of phenol;
0.25 mol of Na was added in small portions while
purging with Ar. After the reaction completion, a
solution of 0.25 mol of N-phenylbenzimidoyl chloride
in dioxane was slowly added. After stirring for 15 h,
the mixture was poured onto 300 ml of ice and placed
in a freezing chamber for 10 h, after which it was
allowed to warm up to room temperature. The precip-
itate was filtered off and recrystallized from absolute
ethanol; yield 87.4%.
REFERENCES
1. Sanzhizhapov, D.B., Tonevitskii, Yu.V., Mogno-
nov, D.M., and Doroshenko, Yu.E., Zh. Prikl. Khim.,
2003, vol. 76, no. 4, pp. 642 646.
2. Sokolov, V.V., Gerasimov, V.D., Savinov, V.M., and
Belyakov, V.K., Termostoikie aromaticheskie poliami-
dy (Heat-Resistant Aromatic Polyamides), Moscow:
Khimiya, 1975.
Found, %: C 83.18, H 5.90, N 4.95.
C19H15NO.
Calculated, %: C 83.52, H 5.49, N 5.13.
N, N-Diphenylbenzamide was prepared by rear-
rangement of phenyl N-phenylbenzimidate in an inert
atmosphere at 250 C for 13 h; mp 179.5 179.8 C (cf.
179.6 C [4]).
3. Vatsuro, K.V. and Mishchenko, G.L., Imennye reaktsii
v organicheskoi khimii (Named Reactions in Organic
Chemistry), Moscow: Khimiya, 1976.
4. Potekhin, A.A., Svoistva organicheskikh soedinenii:
Spravochnik (Properties of Organic Compounds: Hand-
book), Leningrad: Khimiya, 1984.
Polyarylene benzimidates were prepared in a
50-ml three-necked flask equipped with a stirrer and
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 79 No. 3 2006