Features of polychlorinated biphenyls nitration

Article abstract of DOI:10.1134/S1070363215070063

Nitration of mono-, di-, and trichlorobiphenyls has been studied. The nitration degree depends on the number of chlorine substituents; one to four nitro groups can be introduced. The conclusions have been confirmed by results of nitration of the "Trikhlorbifenil" technical mixture of polychlorinated biphenyls.

Full text of DOI:10.1134/S1070363215070063

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 7, pp. 1611–1616. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © T.I. Gorbunova, M.G. Pervova, K.A. Plotnikova, V.I. Saloutin, O.N. Chupakhin, 2015, published in Zhurnal Obshchei Khimii, 2015,
Vol. 85, No. 7, pp. 1085–1091.
Features of Polychlorinated Biphenyls Nitration
T. I. Gorbunova, M. G. Pervova, K. A. Plotnikova, V. I. Saloutin, and O. N. Chupakhin
Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences,
ul. S. Kovalevskoi/Akademicheskaya 22/20, Yekaterinburg, 620137 Russia
e-mail: gorbunova@ios.uran.ru
Received March 5, 2015
Abstract—Nitration of mono-, di-, and trichlorobiphenyls has been studied. The nitration degree depends on
the number of chlorine substituents; one to four nitro groups can be introduced. The conclusions have been
confirmed by results of nitration of the “Trikhlorbifenil” technical mixture of polychlorinated biphenyls.
Keywords: polychlorinated biphenyls, nitration, gas chromatography, mass spectrometry
DOI: 10.1134/S1070363215070063
A combination of different methods is generally
utilized for neutralization of polychlorinated biphenyls,
large-scale industrial waste; development of such
methods has remained a topical problem nowadays. In
particular, the thermal, pyrotechnical, electrochemical,
biological, and chemical methods have been described
(cf. [1, 2]). Hydrodechlorination [3] has been
recognized as the most important chemical method of
polychlorinated biphenyls neutralization, whereas
other processes (substitutive dechlorination, oxidation,
etc.) has been less developed.
The results of earlier studies have not allowed
prediction of reactivity of mono-, di-, and trichlori-
nated biphenyls. However, the relevant information is
of practical importance, since these compounds are
components of the industrial polychlorinated biphenyls
mixtures such as Arochlor 1016, Arochlor 1242,
Arochlor 1248, Kanechlor 300, Kanechlor 400, etc.
[11]. Nitration of such industrial mixtures followed by
reduction can yield the amino derivatives, valuable
intermediates of polycondensation reaction or
production of benzidine type dyes.
The sulfonation reaction has been the most studied
In view of the above, in this work we studied
nitration of individual chlorinated biphenyls.
electrophilic
substitution
process
involving
polychlorinated biphenyls [4–7]. However, these
studies have been performed using the industrial
samples, and their results has been patented. Reactivity
of individual polychlorinated biphenyls towards
sulfonation has not been studied.
Mononitro [12, 13] and dinitro [14] derivatives of
biphenyl have been described. The mononitro deriva-
tives are commonly prepared indirectly from the mono-
nuclear derivatives [13] rather than via direct nitration
of biphenyls. A method of 4-nitrobiphenyl production
with the yield of 84% upon biphenyl treatment with a
mixture of sodium nitrite and an acid (the elemental
formula CH0.35O0.35S0.14) at room temperature has been
described in [15]. Biphenyl treatment with the
conventional nitrating mixture has afforded 4,4'-
dinitrobiphenyl [14] and 3,5,4'-trinitro-4-hydroxy-
biphenyl [16]. The products of deeper nitration of
biphenyl have not been found in the reaction mixture.
General features of nitration of the Sovol industrial
mixture {containing tri- (2%), tetra- (20%), penta-
(55%), hexa- (18%), and heptachlorinated (2%)
biphenyls [8, 9]} have been studied earlier [10].
Further GC–MS study [11] has revealed that
tetrachlorinated biphenyls yield exclusively dinitro
derivatives (16%), pentachlorinated biphenyls are
transformed into mononitro (9%) and dinitro (51%)
derivatives, hexachlorinated biphenyls afford the
mononitro (12%) and dinitro (7%) derivatives under
conditions of the nitration reaction, whereas nitro
derivatives of tri- and heptachlorinated biphenyls have
not been detected in the reaction mixture.
In order to simplify GC–MC identification of nitro
derivatives of chlorinated biphenyls, we first studied
nitration of unsubstituted biphenyl. The substrate was
completely converted under the chosen reaction
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GORBUNOVA et al.
Scheme 1.
Scheme 2.
NH2
Clх
+
Cly
100oC, 7 h
[HNO3 + H2SO4]
Clх+у
isoamilonitrite
120_130oC (or bp),
18_24 h
(NO2)4
Ib (95.8%)
(NO2)3
Ia (4.2%)
IIa_VIa
Clх+у
[HNO3 + H2SO4]
100oC, 7 h
conditions to yield products of deeper nitration than
were generally reported in the literature (Scheme 1).
Tetranitrobiphenyls Ib (four isomers) were the major
products, whereas content of the single trinitrobiphenyl
isomer Ia in the products mixture was lower.
(NO2)n
IIb, IIc_IVb, IVc
II, x = 1 (m-Cl), y = 0, n = 3 (b, 79.9%), 4 (c, 20.1%); III,
x = 1 (n-Cl), y = 1 (о'-, m'- or p'-), n = 2 (b, 90%), 3 (c,
10%); IV, х = 2 (m-, p-2Cl), y = 0, n = 2 (b, 19.9 %), 3 (c,
80.1%); V, x = 3 (o, m, p-3Cl), y = 0, n = 2 (b, 77.5%), 3
(c, 22.5%); VI, x= 3 (o, o, p-3Cl), y = 0, n = 2 (b, 98.8%),
3 (c, 1.2%).
Introduction of a chlorine atom in biphenyl struc-
ture significantly affected its reactivity in the nitration
process. In particular, 3-chlorobiphenyl IIa (prepared
from 3-chloroaniline and benzene via the Gomberg–
Bachmann reaction [17–19]; PCB 2 according to the
BZ nomenclature accepted by IUPAC [17]) gave
mainly trinitrochlorobiphenyls IIb (eight isomers) and
smaller amounts of tetranitrochlorobiphenyls IIc (two
isomers) (Scheme 2); the conversion of compound IIa
was of 100%.
Thus the investigation of nitration of mono-, di-,
and trichlorobiphenyls showed that the increased
number of chlorine substituents in biphenyl scaffold
significantly decreased the fraction of deep nitration
products.
The result of nitration of dichlorobiphenyls depended
on the substituents location. When the chlorine atoms
were located in the different aromatic rings (in particular,
nitration of a mixture of 2,4'-dichlorobiphenyl PCB 8,
3,4'-dichlorobiphenyl PCB 13, and 4,4'-dichlorobiphenyl
PCB 15 was studied), the reaction mainly gave the
dinitro derivatives IIIb (eight isomers) (Scheme 2).
When the two chlorine atoms were located at the same
aromatic ring (3,4-dichlorobiphenyl PCB 12, IVa), the
reaction afforded trinitrodichlorobiphenyls IVc (five
isomers) (Scheme 2). Tetranitrodichloro derivatives and
the starting compounds were not detected in the mixtures.
One of the industrial mixtures of polychlorinated
biphenyls widely used in Russia is the Trikhlorbifenil,
utilized in power capacitors. Our analysis (gas chro-
matography with flame ionization detector and GC–
MS) showed that the Trikhlorbifenil mixture used in
this work (VIIa) was composed of di- (14%), tri-
(48%), tetra- (30%), and pentachlorinated (4%)
biphenyls. That composition roughly corresponded to
the Arochlor 1242 mixture [20].
The nitration of the VIIa substrate resulted in its
complete conversion according to Scheme 3 (the
numbers of the isomers are given in parentheses). We
found by GC–MS analysis dinitro derivatives VIIc of
tri- and tetrachlorinated biphenyls as the major
nitration products (Fig. 1), whereas the fraction of
trinitro derivatives VIId of di- and trichlorinated
biphenyls was relatively low. Hence, the outcome of
nitration of the VIIa mixture coincided with the
conclusions derived from the investigation of nitration
of the individual di- and trichlorinated biphenyls III–VIa.
Nitration of the trichlorobiphenyls with the chlorine
atoms located in the same aromatic ring (2,3,4-tri-
chlorobiphenyl PCB 29, Va and 2,4,6-trichlorobi-
phenyl PCB 30, VIa) gave the dinitrotrichloro-
biphenyls as the major products: Vb (six isomers) and
VIb (three isomers), respectively (Scheme 2). The
minor reaction products were trinitro derivatives Vc
(three isomers) and VIc (three isomers), respectively;
conversion of the starting substrates was complete.
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FEATURES OF POLYCHLORINATED BIPHENYLS NITRATION
Scheme 3.
the signals of the [M – OH], [M – NO], [M – NO2],
[M – 2NO2], etc ions of variable intensity.
The fragmentation of molecular ions of dinitro
derivatives IIIb occurred via three pathways. Two of
them were similar to the above described: (a) the
molecular ion peak was absent, and the [M – NO2] ion
peak was the strongest one (Fig. 1) and (b) the
molecular ion peak was the strongest one (Fig. 2). In
those cases, the molecular ion fragmentation occurred
via sequential elimination of the nitro groups, followed
by elimination of chlorine atoms. In the third case, an
unusual signals pattern was observed: the intensity of
the molecular ion peak was 5%, and the strongest
signal belonged to the [M – Cl] ion (Fig. 3). Further
signals found in the spectrum were assigned to the
[M – Cl – NO], [M – Cl – NO2 – CO], and [M – Cl –
2NO2 – Cl] ions. Hence, the third fragmentation pathway
occurred via sequential elimination of a chlorine atom,
a nitro group, and another chlorine atom.
Clх
VII
100oC, 7 h
[HNO3 + H2SO4]
NO2
(NO2)3
(NO2)2
Clх
Clх
Clх
VIIa
VIIc
VIIb
х
2
3
4
5
VIIa
VIIb
VIIc
4.7 (4)
3.3 (7)
–
–
5.9 (5)
56.4 (13)
21.4 (17)
0.5 (5)
0.3 (1)
1.7 (3)
0.7 (2)
Mass spectra of the trinitro derivatives IIIc
demonstrated the possibility of all three above-
described fragmentation paths. Mass spectra of di- (Vb
and VIb) and trinitro (Vc and VIc) derivatives of the
trichlorobiphenyls (Va and VIa, respectively)
evidenced two possible fragmentation pathways:
(a) giving rise to the strongest [M – Cl] ion peak, with
the molecular ion peak intensity of 1–2% and
(b) havng the molecular ion peak as the strongest one
and proceeding with the formation of the [M – O],
[M – NO], and [M – NO2] ions. The fragmentation of
the nitro derivatives VIIb–d occurred similarly, via the
two pathways yielding either the [M – Cl] ion peak
with 100% intensity and the molecular ion peak with
1–5% intensity or the molecular ion peak as the
strongest one.
–
To summarize, the direct nitration of poly-
chlorinated biphenyls was a non-selective process, the
reaction outcome being mainly affected by the spatial
factors. The congeners with less of the electrophilic
chlorine substituents in the biphenyl molecule
underwent deeper nitration; one to four of nitro groups
could be introduced in the substrate under the used
reaction conditions.
The above-given quantitative data were obtained
using gas chromatography with flame ionization
detecting and internal normalization of the peak areas.
Such analysis was subject to certain systematic errors
due to the unequal sensitivity of the detector to the
derivatives with different number of nitro groups and
overlap of elution peaks of several products.
Therefore, we further analyzed the reaction mixtures
applying GC–MS technique; most of the recorded
mass spectra of the nitro derivatives of polychlorinated
biphenyls contained the molecular ion peaks.
EXPERIMENTAL
Chromatograms of the starting compounds and the
nitration products were recorded using a Shimadzu
GC-2010Plus gas–liquid chromatograph equipped with
a flame ionization detector. Other conditions were as
follows: a GsBP-5MS quartz capillary column, PDMS
with 5% of grafted phenyl groups as the stationary
phase, length 30 m, inner diameter 0.25 mm, stationary
phase film thickness 0.25 µm; nitrogen as carrier gas,
split ratio 1 : 30; starting column temperature 40°С
(3 min isotherm followed by heating to 280°С at a rate
10 deg/min), evaporator temperature 250°С, and
detector temperature 300°С.
The fragmentation of molecular ions of di- (IVb),
tri- (Ib, IIb, and IVc), and tetranitro (Ic and IIc)
derivatives occurred via two pathways. In the first
case, the molecular ion peak was the strongest one in
the spectrum; in the second case, the molecular ion
peak intensity was below 1%, and the strongest one
was the [M – NO2] ion peak. However, in both cases,
the molecular ion fragmentation occurred via
sequential elimination of the nitro groups giving rise to
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GORBUNOVA et al.
I, %
m/z
Fig. 1. Mass spectrum of dinitro derivatives IIIb [(C12H6Cl2(NO2)2] (the first type of molecular ion fragmentation).
I, %
m/z
Fig. 2. Mass spectrum of dinitro derivatives IIIb [(C12H6Cl2(NO2)2] (the second type of molecular ion fragmentation).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 7 2015

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FEATURES OF POLYCHLORINATED BIPHENYLS NITRATION
I, %
m/z
Fig. 3. Mass spectrum of dinitro derivatives IIIb [(C12H6Cl2(NO2)2] (the third type of molecular ion fragmentation).
Mass spectra of the products were obtained using
an Agilent GC 7890A MSD 5975 C inert XL EI/CI
tandem gas chromatograph–mass spectrometer instru-
ment. Chromatography conditions were as follows: an
HP-5MS quartz capillary column, PDMS with 5% of
grafted phenyl groups as the stationary phase, length
30 m, inner diameter 0.25 mm, stationary phase film
thickness 0.25 µm; helium as carrier gas, split ratio
1 : 50; starting column temperature 40°С (3 min
isotherm followed by heating to 290°С at a rate
10 deg/min), evaporator temperature 250°С, transition
chamber temperature 280°C, source temperature 230°C,
and quadrupole temperature 250°С. Mass spectrum
recording conditions were as follows: quadrupole
detector, scanning over the whole ion current at mass
range of 20–1000 Da; EI at 70 eV.
1H NMR spectra of the individual polychlorinated bi-
phenyls IIa and IVa–VIa coincided with the reference
data [17, 21]. The congeners mixture IIIa was a viscous
yellow liquid, bp 173–182°С (5 mmHg). Structures of
the compounds PCB 8, PCB 13, and PCB 15 constitut-
ing the mixture were confirmed by their mass spectra.
Nitration (general procedure). 11 mL of the
nitrating mixture prepared from 5 mL of conc. HNO3
and 6 mL of conc. H2SO4 on cooling was added
dropwise to 0.001 mol of a biphenyl (or a poly-
chlorinated biphenyl congener) at room temperature
upon stirring. The reaction mixture was heated on a
boiling water bath during 7 h at vigorous stirring. After
cooling the mixture to ambient, the viscous organic
layer or the solid reaction product was separated and
washed with water several times. IR spectrum, ν, cm–1:
2990–2996, 3008–3035 (C–H); 1332–1337, 1530–
1536 (NO2); 892–898 (C–Cl).
1Н NMR spectra were registered using a Bruker
DRX-400 spectrometer at 400 MHz with reference to
Me4Si in CD3OD. Elemental analysis was performed
using a Perkin–Elmer CHN РЕ 2400 automated
analyzer. IR spectra were registered using a Perkin–
Elmer Spectrum One spectrophotometer.
Mixture of nitro derivatives (IIb and IIc). Yield
91% (with respect to compound IIb). Found, %: С
44.06; Н 2.01; Cl 10.67; N 13.15. C12H7ClN3O6.
Calculated, %: С 44.40; Н 2.17; Cl 10.92; N 12.94.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 7 2015

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GORBUNOVA et al.
7. RF Patent 2304572, 2006, Byull. Izobret., 2007, no. 23.
Mixture of nitro derivatives (IIIb and IIIc).
Yield 97% (with respect to compound IIIb). Found,
%: С 44.54; Н 1.97; Cl 22.19; N 9.78. C12H6Cl2N2O4.
Calculated, %: С 46.03; Н 1.93; Cl 22.65; N 8.95.
8. Kirichenko, V.E., Pervova, M.G., Promyshlennikova, E.P.,
and Pashkevich, K.I., Analit. Kontrol’, 2000, vol. 4,
no. 1, p. 41.
9. Piterskikh, I.A., Kirichenko, V.E., Pervova, M.G., and
Kandakova, V.V., Zav. Lab. Diagnost. Mater., 2001,
vol. 67, no. 8, p. 63.
10. Gorbunova, T.I., Zapevalov, A.Ya., Kirichenko, V.E.,
Saloutin, V.I., and Chupakhin, O.N., Russ. J. Appl.
Chem., 2001, vol. 74, no. 1, p. 118. DOI: 070-
4272/01/7401-0118.
11. Gorbunova, T.I., Pervova, M.G., Zabelina, O.N.,
Saloutin, V.I., and Chupakhin, O.N., Polikhlorbifenily.
Problemy ekologii, analiza i khimicheskoi utilizatsii
(Polychlorobiphenyls. Problems of Ecology, Analysis,
and Chemical Waste), Moscow: Krasand, 2011.
Mixture of nitro derivatives (IVb and IVc). Yield
92% (with respect to compound IVc). Found, %: С
33.73; Н 2.25; Cl 17.87; N 9.14. C12H5Cl2N3O6.
Calculated, %: С 40.25; Н 1.41; Cl 19.80; N 11.73.
Mixture of nitro derivatives (Vb and Vc). Yield
91% (with respect to compound Vb). Found, %: С
37.32; Н 1.55; Cl 28.82; N 8.83. C12H5Cl3N2O4.
Calculated, %: С 41.47; Н 1.45; Cl 30.60; N 8.06.
Mixture of nitro derivatives (VIb and VIc). Yield
97% (with respect to compound VIb). Found, %: С
40.75; Н 1.35; Cl 30.24; N 8.04. C12H5Cl3N2O4.
Calculated, %: С 41.47; Н 1.45; Cl 30.60; N 8.06.
12. Vorozhtsov, N.N., Osnovy sinteza promezhutochnykh
produktov
i
krasitelei (Basics of Synthesis of
Intermediates and Dyes), Moscow: Goskhimizdat, 1955.
Mixture of nitro derivatives (VIIb–VIId). Yield
95% (with respect to compound VIIb). Found, %: С
38.11; Н 1.29; Cl 38.13; N 7.79. C12H4Cl4N2O4.
Calculated, %: С 37.73; Н 1.06; Cl 37.12; N 7.33.
13. Ratniyom, J., Chaiprasert, T., Pramjit, S., Yotphan, S.,
Sangtrirutnugul, P., Srisuratsiri, P., Kongsaeree, P., and
Kiatisevi, S., J. Organomet. Chem., 2014, vol. 752,
p. 161. DOI: 10.1016/j.jorganchem.2013.12.015.
14. Nesmeyanov, A.N., Nachala organicheskoi khimii
(Beginnings of Organic Chemistry), Moscow: Khimiya,
1970, book 2.
ACKNOWLEDGMENTS
This work was financially supported by the
integrated investigation program of Ural Branch,
Russian Academy of Sciences.
15. Shokrolahi, A., Zali, A., and Keshavarz, M.H., Chinese
Chem. Lett., 2007, vol. 18, p. 1064. DOI: 10.1016/
j.cclet.2007.06.031.
16. Kaminskii, A.Ya. and Gittis, S.S., Zh. Obshch. Khim.,
1964, vol. 34, no. 11, p. 3743.
REFERENCES
17. Mullin, M.D., Pochini, C.M., McGrindle, M.R.,
Romkes, M., Safe, S.H., and Safe, L.M., Environ. Sci.
Technol., 1984, vol. 18, p. 468. DOI: 10.1021/es00124a014.
18. Gorbunova, T.I., Pervova, M.G., Zapevalov, A.Ya., and
Saloutin, V.I., Ftornye Zametki, 2012, no. 4. http://
notes.fluorine1.ru/public/2012/4_2012/letters/rusindex.html.
1. Zanaveskin, L.N. and Averyanov, V.A., Russ. Chem.
Rev., 1998, vol. 67, no. 8, p. 713. DOI: 10.1070/
RC1998v067n08ABEH000412.
2. Gorbunova, T.I., Saloutin, V.I., and Chupakhin, O.N.,
Russ. Chem. Rev., 2010, vol. 79, no. 6, p. 511. DOI:
10.1070/RC2010v079n06ABEH004047.
3. Wu, B.-Z., Chen, H.-Y., Wang, S.J., Wai, C.M., Liao, W.,
and Chiu, K.H., Chemosphere, 2012, vol. 88, p. 757.
DOI: 10.1016/j.chemosphere.2012.03.056.
19. Gorbunova, T.I., Pervova, M.G., Saloutin, V.I., and
Chupakhin, O.N., Russ. J. Gen. Chem., 2012, vol. 82,
no. 1, p. 138. DOI: 10.1134/S1070363212010227.
20. Frame, G.M., Fresenius J. Anal. Chem., 1997, vol. 357,
4. RF Patent 2076090, 1994, Byull. Izobret., 1997, no. 9.
5. RF Patent 2231518, 2003, Byull. Izobret., 2004, no. 18 (III).
6. RF Patent 2317157, 2006, Byull. Izobret., 2008, no. 5 (II).
p. 714.
21. Yanagisawa, M., Hayaizu, K., and Yamamoto, O.,
Magn. Res. Chem., 1987, vol. 25, p. 184.
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