Nitration of aromatic hydrocarbons and halobenzenes using NOx catalyzed by solid acid catalysts

Article abstract of DOI:10.1080/00397910903531763

The nitration of aromatics using zeolite as a solid inorganic catalyst and nitric oxides as nitrating agents is a relatively clean process for aromatic nitration. Copyright

Full text of DOI:10.1080/00397910903531763

This article was downloaded by: [University of Arizona]
On: 21 January 2013, At: 23:26
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic Organic
Chemistry
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/lsyc20
Nitration of Aromatic Hydrocarbons and
Halobenzenes Using NOx Catalyzed by
Solid Acid Catalysts
a
a
Manoj A. Pande & Shriniwas D. Samant
a
Department of Chemistry, Institute of Chemical Technology,
Matunga, Mumbai, India
Version of record first published: 09 Nov 2010.
To cite this article: Manoj A. Pande & Shriniwas D. Samant (2010): Nitration of Aromatic
Hydrocarbons and Halobenzenes Using NOx Catalyzed by Solid Acid Catalysts, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
40:24, 3734-3738
To link to this article: http://dx.doi.org/10.1080/00397910903531763
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden.
The publisher does not give any warranty express or implied or make any representation
that the contents will be complete or accurate or up to date. The accuracy of any
instructions, formulae, and drug doses should be independently verified with primary
sources. The publisher shall not be liable for any loss, actions, claims, proceedings,
demand, or costs or damages whatsoever or howsoever caused arising directly or
indirectly in connection with or arising out of the use of this material.

1
Synthetic Communications , 40: 3734–3738, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903531763
NITRATION OF AROMATIC HYDROCARBONS AND
HALOBENZENES USING NOx CATALYZED BY
SOLID ACID CATALYSTS
Manoj A. Pande and Shriniwas D. Samant
Department of Chemistry, Institute of Chemical Technology, Matunga,
Mumbai, India
The nitration of aromatics using zeolite as a solid inorganic catalyst and nitric oxides as
nitrating agents is a relatively clean process for aromatic nitration.
Keywords: Aromatic nitration; nitrogen oxides; zeolites
INTRODUCTION
Aromatic nitration reaction is an important unit chemical process as the
resulting aromatic nitro compounds find diverse applications; main being pre-
[
1]
paration of primary amines through reduction. Classically nitration is carried
out using mixed acid (HNO þ H SO ). This nitration is a hazardous process
3
2
4
with very high E factor. It is a run-away reaction (DH ¼ ꢀ110 kJ=mol for benzene)
and is probably the most potentially hazardous industrial process. This is due to
the heat generated during the reaction which can trigger the power of nitric acid
to degrade organic material exothermically to gaseous products with explosive
violence. The reaction can be carried out in batch mode or continuous mode;
the latter is more suitable for large tonnage intermediates, like nitrobenzene and
nitrotoluene and is attractive for reasons of safety as well as obvious economic
consideration. For large scale mononitration 20=60=20 mixed acid system is
employed i.e., 20% HNO , 60% H SO , 20% H O. Thus a large excess of sulfuric
3
2
4
2
acid is required as the water formed as a by product slows the reaction by diluting
the acid. At the end of the reaction, a large amount of ‘spent acid’ is obtained
which increases the E-factor of the reaction. Moreover, Sulfuric acid is corrosive
and is dangerous to transport and handle. Hence, nitration of aromatics avoiding
sulfuric acid appears to be an attractive alternative. The use of zeolites in aromatic
nitration is a subject of increasing interest, particularly with regards to unusual
Received August 28, 2009.
Address correspondence to Shriniwas D. Samant, Organic Chemistry Research Laboratory,
University Institute of Chemical Technology, N. M. Parekh Road, Mantunga, Mumbai 400019, India.
E-mail: samantsd@yahoo.com
3
734

AROMATIC NITRATION
3735
[2]
regioselectivity. At present, best combination of high yield, high para selectivity
and low solvent use is achieved using a nitric acid, zeolite Hb as catalyst, and
acetic anhydride (for moderately active aromatics) or trifluroacetic anhydride
[
3]
[
2]
(
for deactivated aromatics) as activator. However, carboxylic acid is formed as
a by product. The nitration using nitrogen oxides has been attempted using solid
acid catalysts like zeolites. In some cases oxidant like oxygen or ozone is
[
4]
required. The method where ozone is employed most likely involves dinitrogen
pentoxide, as this is known to be a highly active nitrating agent. The nonacid
method for aromatic nitration using NO =O gives excellent conversion of a wide
2
3
[
5]
variety of aromatic compounds under mild conditions (Kyodai nitration). How-
ever, use of ozone adds to the cost of the process. Fe(III)-catalyzed nitration using
NO -O system requires a long reaction time (12 to 36 h) and large amount of
2
2
[6]
nitrogen dioxide and catalyst. Vapor phase nitration of benzene over mixed metal
oxides (silica-alumina, zinc oxide-titania, tungsten oxide-molybdenum oxide) using
[
7]
NO is carried out at high temperature and give around 25% of nitrobenzene.
2
Nitration of halobenzenes using NO – O -zeolite system gives good conversion
2
2
[
8]
with enhanced para selectivity after 48 h of reaction time. Thus, nitration using
NOx in presence of suitable acid catalyst appears to be promising.
In our efforts to develop an atom-economic and eco-friendly process for
aromatic nitration, we attempted nitration of aromatic compounds using NOx in
the presence of zeolites. Zeolite b and zeolite Y have 3-dimensional channels and
large pore sizes. Zeolite Hb is a strong bronsted acid and is known to catalyze
nitration reaction.
Nitration of chlorobenzene was attempted as the products are commercially
[
1b,9]
[10]
important
and has been studied earlier under different reaction conditions.
The nitration of chlorobenzene was carried out in the presence of different
ꢁ
amount of zeolite Hb at 40 C. The NOx was generated by reacting HNO with
3
[
P O with some modification in reported method. The amount of P O was taken
11]
2
5
2
5
intentionally excess. The gas so generated was passed through the reaction mixture
using N as carrier gas. After the complete addition of HNO to P O , the flow
2
3
2
5
of nitrogen was continued to ensure the purging of NOx from the generator.
In the absence of catalyst 33% conversion of chlorobenzene was obtained, and the
conversion increased with increasing quantity of the catalyst (Table 1). There was
Table 1. The effect of catalyst amount (zeolite Hb) on the nitration of chlorobenzene (CB) using NOx
a
Selectivity (%)
Catalyst amount (wt %)
wrt wt of CB
a
a
o=p
Entry
Conversion CB (%)
o-
m-
p-
1
3
4
5
0
33.2
42.4
68.1
71.8
31.02
33.49
35.53
27.42
0.0
68.97
65.09
63.87
72.08
0.44
0.51
0.55
0.38
0.75
1
1.65
0.58
0.44
5
Reaction conditions: Chlorobenzene (30 mmol), catalyst zeolite Hb, 1,2-dichloroethane (30 ml), HNO
3
ꢁ
4
ml, P
a
GC.
2
O
5
10 g; temperature 40 C, reaction time 240 min.

3736
M. A. PANDE AND S. D. SAMANT
Table 2. The effect of different catalysts on the nitration of chlorobenzene using NOx
a
Selectivity (%)
a
o=p
Entry
Catalyst
Conversion CB (%)
o-
m-
p-
1
2
3
4
Zeolite Hb
Zeolite Y-H
ZSM-5 Na
Mont K-10
68.1
35.53
48.61
49.84
40.02
0.58
1.66
1.47
1.21
63.87
49.71
48.68
58.78
0.55
0.97
1.02
0.68
47.43
41.33
46.12
Reaction conditions: Chlorobenzene (30 mmol), catalyst 1 wt% wrt wt. of CB, dichloroethane (30 ml),
ꢁ
HNO
a
3
4 ml, P
2
O
5
10 g; temperature 40 C, reaction time 240 min.
GC.
no remarkable difference in conversion from 1 wt% to 5 wt% Hb. Hence 1 wt% of
catalyst amount was used for further study. The reaction was carried out using
1
wt% of different zeolites and Mont K-10 (Table 2).
Among the catalysts, Zeolite Hb was found to give maximum conversion of
chlorobenzene and gave higher selectivity for para nitrochlorobenzene. For Zeolite
H-Y and ZSM-5 Na no selectivity was observed.
Under the optimized conditions different less activated aromatics were nitrated
(Table 3).
After 240 min. of reaction time, toluene was completely consumed, however
a range of products including isomers of mononitrotoluene, dinitrotoluene, and
oxidized products were found. When nitration of aniline and benzaldehyde was tried
under the same conditions, oxidation products were observed. Nitration of
para-dichlorobenzene gave 2,5-dichloro-1-nitrobenzene in a trace quantity.
Table 3. Nitration of aromatic hydrocarbons and halobenzenes using NOx in presence of zeolite Hb
b
Selectivity (%)
b
Entry
Substrate
Conversion of substrate (%)
o-
m-
p-
a
1
2
3
4
5
6
7
8
Benzene
Benzene
37
48
–
–
–
–
–
–
Chlorobenzene
Naphthalene
Toluene
68.1
c
98
35.53
–
0.58
–
63.87
–
100
15
23
30
40
1
19
70
60
Iodobenzene
Bromobenzene
Orthodichloro Benzene
–
42
12
–
d
e
12 (2,3DCNB)
88 (3,4DC4NB)
Reaction conditions: substrate (30 mmol), catalyst zeolite Hb 1 wt% wrt wt. of substrate, dichloroethane
ꢁ
(
30 mL), HNO
a
3
4 ml, P
2
O
5
10 g; temperature 40 C, reaction time 240 min.
Without catalyst.
GC and GC-MS.
b
c
Exclusive 1-nitronaphthalene.
2,3-Dichloro-1-nitrobenzene.
d
e
3,4-Dichloro-1-nitrobenzene.

AROMATIC NITRATION
3737
CONCLUSION
In conclusion we have developed a potentially clean nitration process for
weakly activated aromatics using NOx and solid acid zeolite Hb. Sulfuric acid is
totally eliminated in the process. The process is environmentally benign and has
potential for commercialization.
EXPERIMENTAL
General
Solvents: All the solvents were of LR-grade and were purified and dried by the
known procedures before use.
Chemicals: The chemicals were of LR or sometimes AR grade and procured
from M=s s.d fine chemicals, Mumbai; LOBA Chemie, Mumbai; Fluka Chemicals,
A. G, Switzerland; E. Merck (India) Ltd., Mumbai; Aldrich Chemical Company,
Inc., and Lancaster, PA, USA.
Analytical Methods: The progress of the reaction and simultaneous product
formation was carried out by external standard method using a gas chromatographic
technique. For this purpose, Chemito 8610 gas chromatograph with flame ionization
1
2
detector and stainless steel column (OV 17, in. ꢂ 2 m) was used.
GC-MS spectra were recorded on a Shimatzu GC-MS QP 2010 (RTX-WAX,
capillary column, 30 m, 0.25 mm) equipped with an electron capture detector.
All the products reported here are known compounds and their identity was
determined with authentic samples using GC and GC-MS.
Preparation of NOx
Phosphorus pentoxide (10 g) was taken in a three-necked round bottom
flask (100 ml). The flask was kept in an electrically heated oil bath and heated
ꢁ
at 60–65 C. A slow stream of nitrogen gas was passed through the side neck,
to drive the NOx formed. Concentrated nitric acid (70%, 4 ml) was added at a
slow rate (1 drop=min) through a dropping funnel. The gas which evolved was
introduced through a glass tube into the flask containing substrate dissolved in
ethylenedichloride (EDC).
General Procedure of Nitration
Substrate (30 mmol) was taken in a three-necked round bottom flask (50 ml)
and dissolved in ethylenedichloride (30 ml). The flask was kept in an oil bath main-
ꢁ
tained at 40–45 C. The solution was stirred magnetically. The NOx from the NOx
generator was bubbled through a glass tube in the solution containing substrate.
ACKNOWLEDGMENT
Financial support by the Government of India under ‘‘Technical Education
Quality Improvement Programme’’ (TEQIP) is gratefully acknowledged.

3738
M. A. PANDE AND S. D. SAMANT
REFERENCES
1
. (a) Olah, G. A.; Malhotra, R.; Narang, S. C. Nitration Methods and Mechanisms;
VCH Publications: New York, 1989; (b) Schofield, K. Aromatic Nitration; Cambridge
University Press: Cambridge, 1980.
2
3
4
. Smith, K.; Gibbins, T.; Millar, R. W.; Claridge, R. P. A novel method for the nitration of
deactivated aromatic compounds. J. Chem. Soc. Perkin Trans. 1 2000, 12753–2758.
. Smith, K.; Musson, A.; Deboos, G. A. A novel method for the nitration of simple aro-
matic compounds. J. Org. Chem. 1998, 63, 8448–8454.
. Suzuki, H.; Mori, T. Ozone-mediated nitration of chloro- and bromo-benzenes and some
methyl derivatives with nitrogen dioxide. High ortho-directing trends of the chlorine and
bromine substituents. J. Chem. Soc. Perkin Trans. 2 1994, 479–484.
5
. (a) Mori, T.; Suzuki, H. Ozone-mediated nitration of aromatic compounds with lower
oxides of nitrogen. (The Kyodai-nitration). Synlett. 1995, 5, 383–392; (b) Peng, X.;
Suzuki, H. Regioselective double kyodai nitration of toluene and chlorobenzene over
zeolites. High preference for the 2,4-dinitro isomer at the second nitration stage.
Org. Lett. 2001, 3, 3431–3434.
6
. Suzuki, H.; Yonezawa, S.; Nonoyama, N.; Mori, T. Iron(III)-catalysed nitration of
non-activated and moderately activated arenes with nitrogen dioxide–molecular oxygen
under neutral conditions. J. Chem. Soc., Perkin Trans. 1 1996, 2385–2389.
. Sato, H.; Hirose, K. Vapor-phase nitration of benzene over solid acid catalysts: Nitration
with nitric oxide (NO ). Appl. Catal. A: Gen. 1998, 174, 77–81.
2
. Smith, K.; Almeer, S.; Black, S. J. para-Selective nitration of halogenobenzenes using a
nitrogen dioxide–oxygen–zeolite system. Chem. Commun. 2000, 1571–1572.
7
8
9
. (a) Taylor, R. Electrophillic Aromatic Substitution; Wiley: Chichester, 1990; (b) Frank, H.
G.; Stadelhofer, J. W. Industrial Aromatic Chemistry; Springer: Berlin, 1988, chap 5.
1
0. (a) Qian, H.; Ye, Z.-W.; Lu, C.-X. Investigation on HZSM-5 assisted selective nitration of
chlorobenzene with N ; Chinese J. Energ. Mater. 2007, 15, 56–59; (b) Cheng, G.-B.; Lu,
C.-X. Study on regioselective synthesis of mononitrochlorobenzene on SO4 =WO -ZrO
2 5
O
2ꢀ
3
2
catalysts. Hanneng Cailiao=Energ. Mater. 2002, 10, 168–170; (c) Veretennikov, E. A.;
Lebedev, B. A.; Tselinskii, I. V. Nitration of chlorobenzene with nitric acid in a
continuous installation. Russ. J. Appl. Chem. 2001, 74, 1872–1876. (d) Parida, K. M.;
Pattnayak, P. K. Sulphated zirconia: An efficient paraselective catalyst for mononitration
of halobenzenes. Catal. Lett. 1997, 47, 255–257; (e) Choudary, B. M.; Sarma, M. R.;
3
þ
Kumar, K. Fe -Montmorillonite catalyst for selective nitration of chlorobenzene. J.
Mol. Catal. A – Chemical 1994, 87, 33–38; (f) Veretennikov, E. A.; Lebedev, B. A.;
Tselinskii, I. V. Kinetics and mechanism of the nitration of chlorobenzene with nitric acid.
Russ. J. Org. Chem. 2001, 37, 964–968.
11. Caesar, G. V.; Goldfrank, M. Nitration of starches with nitrogen pentoxide in presence of
sodium fluoride. J. Am. Chem. Soc. 1946, 68, 372–375.