This article was downloaded by: [University of Washington Libraries]

On: 02 December 2014, At: 11:14

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

Green Chemistry Letters and Reviews

Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/tgcl20

The use of nano supported nickel catalyst in reduction

of p-nitrophenol using hydrazine as hydrogen donor
a b c
Islam Hamdy Abd El Maksod & Tamer S. Saleh
a
Physical Chemistry Department , National Research Centre , Cairo, 12622, Egypt
b
Chemistry Department, Faculty of Science , King Abdul Aziz University , Jeddah, 21533,
Saudi Arabia
c
Green Chemistry Department , National Research Centre , Cairo, 12622, Egypt
Published online: 30 Jul 2010.

To cite this article: Islam Hamdy Abd El Maksod & Tamer S. Saleh (2010) The use of nano supported nickel catalyst in
reduction of p-nitrophenol using hydrazine as hydrogen donor, Green Chemistry Letters and Reviews, 3:2, 127-134, DOI:
10.1080/17518251003596143

To link to this article: http://dx.doi.org/10.1080/17518251003596143

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in
the publications on our platform. Taylor & Francis, our agents, and our licensors make no representations or
warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Versions
of published Taylor & Francis and Routledge Open articles and Taylor & Francis and Routledge Open Select
articles posted to institutional or subject repositories or any other third-party website are without warranty
from Taylor & Francis of any kind, either expressed or implied, including, but not limited to, warranties of
merchantability, fitness for a particular purpose, or non-infringement. Any opinions and views expressed in this
article are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The
accuracy of the Content should not be relied upon and should be independently verified with primary sources
of information. Taylor & Francis shall not be liable for any losses, actions, claims, proceedings, demands,
costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in
connection with, in relation to or arising out of the use of the Content.

This article may be used for research, teaching, and private study purposes. Terms & Conditions of access and
use can be found at http://www.tandfonline.com/page/terms-and-conditions

It is essential that you check the license status of any given Open and Open Select article to confirm
conditions of access and use.
 Green Chemistry Letters and Reviews
Vol. 3, No. 2, June 2010, 127
134

RESEARCH LETTER
The use of nano supported nickel catalyst in reduction of p-nitrophenol using
hydrazine as hydrogen donor
Islam Hamdy Abd El Maksoda,b and Tamer S. Salehc*

a
Physical Chemistry Department, National Research Centre, Cairo 12622, Egypt; bChemistry Department, Faculty of Science,
King Abdul Aziz University, Jeddah 21533, Saudi Arabia; cGreen Chemistry Department, National Research Centre,
Cairo 12622, Egypt
(Received 19 April 2009; final version received 23 November 2009)
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

p-Aminophenol was prepared by hydrogenation of p-nitro phenol over nano-sized nickel catalysts supported on
two different supports, SiO2 and Al2O3. Hydrazine hydrate was used as hydrogen source in this reaction. Several
loadings of nano-sized Ni were used, thus 20, 5, and 2.5 wt% were prepared. X-ray diffraction (XRD) and
electron spin resonance (ESR) were employed to investigate the prepared catalysts. The Ni/Al2O3 was found to be
more effective and give high durability. The catalytic activity of the reaction was found to be influenced by both
the crystallinity of the nickel and the strain among nano-sized nickel particles. The prepared catalysts showed
higher catalytic activity, especially at lower loading. During the reaction, a detectable change of the color was
observed from yellow to green and finally to colorless, which enable us to suppose a mechanism of this reaction.
Keywords: nano nickel; hydrogenation; p-nitrophenol; p-aminophenol; catalytic activity; XRD; ESR

Introduction high pressure. The electrolytic reduction needs acidic

Catalysis is considered to be highly valuable in science. or alkaline catholite, and the desired product yield is
This is partly because using the appropriate catalyst very low. The homogeneous catalytic hydrogenation
will reduce energy and thus reduce the impact on the uses expensive catalysts in the form of complexes.
environment. In addition, catalysis is listed as one of Although the heterogeneous catalytic hydrogenation
the principles of green chemistry. The most important with supported metals (palladium, platinum, or ruthe-
challenge in catalysis is to synthesize a catalyst with nium) is very effective, the complexes need special
100% yield and 100% selectivity. With respect to the attention while dealing with them, because of their
environment, the catalyst that reduces waste and is flammable nature in the presence of air.
economical will be the better catalyst (1,2). Among all previously mentioned methods, direct
p-Aminophenol (PAP) is considered to be one of catalytic hydrogenation of PNP to PAP becomes the
the most important intermediates in the manufactur- most important one, because it could be an efficient and
ing of many analgesic and antipyretic drugs, such as greener route for synthesis (9). Raney nickel (15), nano-
paracetamol, acetanilide, and Phentacin (3
9). It can sized nickel (16), and several noble metal catalysts such
be also utilized as a developer in photography with as Pd/C9 have been used as catalysts for this reaction.
trade names of activol and azol and also in chemical Due to their cost-effectiveness and their higher cataly-
dye industries (10). tic activity, supported nickel catalysts are widely used
There are many methods used in the preparation of in such reactions (17
23). Although the supported and
PAP from p-nitrophenol (PNP) such as metal/acid unsupported nickel catalysts have been used for a long
reduction (11), catalytic hydrogenation (12), electro- time in hydrogenation reactions, only a few recently
lytic reduction (13), homogeneous catalytic transfer published manuscripts deal with hydrogenation of
hydrogenation (14), and heterogeneous catalytic PNP with nano nickel metal catalysts (24
27).
transfer hydrogenation. Although all of these methods Most of this recent research used nano supported
are still used today, each method has its shortcoming. or unsupported nickel metal catalyst with high
For instance, the metal/acid system is not selective and pressure of molecular hydrogen as a hydrogen source.
requires strong acidic medium. The catalytic hydro- Although nano nickel catalyst showed high catalytic
genation uses hydrogen gas with drastic conditions at activity, it requires high relative temperature and

*Corresponding author. Email: tamsaid@yahoo.com

ISSN 1751-8253 print/ISSN 1751-7192 online

# 2010 Taylor & Francis
DOI: 10.1080/17518251003596143
http://www.informaworld.com
 128 I.H.A. El Maksod and T.S. Saleh

pressure, which is not economically viable. The use of In contrast to the supported SiO2 catalyst, the
alternative hydrogen sources for hydrogenation of degree of the crystallinity of Ni on the Al2O3 support
PNP to PAP has been reported very little in the remains nearly unchanged after using the catalyst for
literature. For example, hydrazinum monoformate five times under the same conditions (Figure 2). This
was used with Raney nickel as an alternative hydro- may be explained by the possibility of easier trans-
gen source for the hydrogenation of aromatic nitro formation of nickel from crystalline into amorphous
compounds (25). However, the use of hydrazine phase on SiO2 than that on Al2O3 support. Moreover,
monoformate has several disadvantages such as this may be related to the difference in metal support
the possibility of interaction of nickel with a formate interaction between SiO2 and Al2O3.
anion to form nickel format. Furthermore, the XRD diffractograms of 5 wt%
In this manuscript, we report herein on the utility Ni/SiO2 catalyst before and after using two times
of hydrazine hydrate as an alternative source of with ratio 1:5 wt:wt Ni:PNP (Figure 3), showed a
hydrogen with supported nano nickel catalysts as a sharp decrease in the degree of crystallinity of Ni
system for reduction of aromatic nitro compounds metal after only two times of use.
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

using PNP as an example. Only H2 and N2 are the In contrast, the XRD diffractograms of 5 wt%
products of the catalytic decomposition of hydrazine Ni/Al2O3 catalyst before and after using five times
hydrate used over nano-sized nickel catalyst in this with ratio 1:5 wt:wt Ni:PNP (Figure 4), exhibit only
reduction system. We used SiO2 and Al2O3 as
a very small change in the degree of crystallinity of
supports for the nano nickel particles comparing
Ni metal.
them to unsupported commercial Raney nickel cata-
Moreover, the XRD diffractograms of 2.5 wt%
lyst. XRD and ESR techniques were employed to
Ni/SiO2 and Ni/Al2O3 catalysts showed no crystalline
characterize the prepared nano-sized nickel catalysts.
Ni metal at all which attributed to the very small
amount of Ni loaded being beyond the detection limit
of the XRD technique. The crystallite size of Ni for
Results
all samples under investigation was determined
XRD studies according to the Scherrer equation (28):
XRD analysis was applied to follow up the change in
the crystallinity of Ni metal phase before and after
using the catalysts samples in the reaction. Thus, the d0:941l=BcosuB ;
Ni metal phase (Figure 1(a)) in 20 wt% Ni/SiO2
catalyst sample exhibits an observable degree of
crystallinity. Moreover, after using the catalyst for where l is the wavelength, B is the full width at half
five successive times with a ratio of 1:5 wt:wt Ni:PNP maximum (FWHM) of the Bragg’s peak corrected
nearly no crystalline Ni could be observed from XRD using the corresponding peak in micro-sized powder,
diffractograms (Figure 1(b)). and uB is the Bragg’s angle.

300 300
a- 20%Ni/SiO2 freshly prepared a- 20%Ni/Al2O3 freshly prepared
b- 20% Ni/Al2O3 after
b- 20% Ni/SiO2 after five times of using
250 250 five times of using

b Ni b
200 200 Ni
Ni
Intensity (a.u.)

Intensity (a.u.)

150 Ni
150

100 100 Ni
Ni
Ni
50 a Ni 50 a Ni

0 0
20 30 40 50 60 70 80 20 30 40 50 60 70 80
2θ 2θ

Figure 1. XRD diffractograms of 20 wt% Ni/SiO2 catalyst Figure 2. XRD diffractograms of 20 wt% Ni/Al2O3
(a) freshly prepared and (b) after fifth time of using. catalyst (a) freshly prepared and (b) after fifth time of use.
 Green Chemistry Letters and Reviews 129

40

35
Ni
20% Ni/SiO2
30 b

25
Intensity (a.u.)

20
a- 5% Ni/SiO2 Freshly prepared
15 5% Ni/SiO2
b- 5% Ni/SiO2 used two times
10
Ni
5 a
2.5% Ni/SiO2
0
500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

20 30 40 50 60 70 80
Field [G]
2θ
Figure 5. ESR spectra of 2.5, 5, and 20 wt% Ni/SiO2
Figure 3. XRD diffractograms of 5 wt% Ni/SiO2 catalyst catalyst.
(a) freshly prepared and (b) after second time of use.
only remaining possibility to explain this phenom-
ESR spectra
enon is that there is a spin
spin interaction between
The ESR technique is employed in this research to nano nickel particles or, in other words, strain
investigate the nickel metal on different catalyst between nano nickel particles (28
30).
samples before and after use in the hydrogenation To prove this assumption, we make a successive
reaction. The ESR signals were found to be suffering solid
solid dilution of each sample with its bare sup-
from severe anisotropy (Figures 5
11), especially at port until all anisotropy of the ESR signal dis-
higher loading concentrations. In addition, lower appears (i.e. only one isotropic signal centered at
magnetic field signals are observed and found to g2.2 related to nickel metal appeared, e.g. Figure
overlap the other signals over the whole range of the 11). From this signal, the particle size of nickel can
magnetic field. This may be explained if we assume a be estimated. Thus, in 1970 Kawabata (31) demon-
spin
spin interaction to exist. To explain this assump- strated his famous relation hypothesizing that the
tion, it may be better to take a look at the electronic broadening of ESR signal of nano metal particles is
configuration of the nickel metal. Thus, Ni(0) contains affected by the quantum size effect and can be
two electrons in the 3d orbital; however, these elec- correlated to the size of the nano metal particle.
trons seem to be degenerate and can not result in such Accordingly, direct relationship between the line
severe interactions appearing in the ESR spectra. The width DHpp (or peak-to-peak width) of the signal of

100
90 Ni
80 Al2O3 20% Ni/Al2O3
70 Ni
b
Intensity (a.u.)

60
50
a- 5% Ni/Al2O3 freshly prepared
40
b- 5% Ni/Al2O3 used five times 5% Ni/Al2O3
30 Ni
Al2O3
20
Ni a
10
2.5% Ni/Al2O3
0

20 30 40 50 60 70 80 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
2θ Field [G]

Figure 4. XRD diffractograms of 5 wt% Ni/Al2O3 catalyst Figure 6. ESR spectra of 2.5, 5, and 20 wt% Ni/Al2O3
(a) freshly prepared and (b) after fifth time of use. catalyst.
 130 I.H.A. El Maksod and T.S. Saleh

20% Ni/SiO2 new

5% Ni/SiO2

20% Ni/SiO2 fifth time used

5% Ni/SiO2 used two times

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

Field [G] Field [G]

Figure 7. ESR spectra of 20 wt% Ni/SiO2 catalyst, freshly Figure 9. ESR spectra of 5 wt% Ni/SiO2 catalyst, freshly
prepared and after fifth time of using at 1:5 wt:wt of prepared and after fifth time of using at 1:5 wt:wt of
Ni:PNP. Ni:PNP.

nano particle in ESR spectra and its particle size is anisotropy of the ESR signal increases. Also 2.5 wt%
given in the following relation: Ni loading samples for both SiO2 and Al2O3 showed
nearly no signal which can be explained that at this
d  a(DHpp )0:5 ; (1) concentration nearly no reduction of Ni can take
where d is the particle size in nm, DHpp is the line place at these mild conditions of reduction.
width of ESR signal in mT, and a is the proportion- Moreover, it can observed that the amount of
ality constant. anisotropy is proportional to the amount of crystal-
The proportionality constant ‘‘a’’ for nickel was line Ni metal. Thus, in Figure 7 the fifth use of 20
previously determined as 1.2 (32). The particle size of wt% Ni/SiO2 catalyst showed nearly no anisotropy
investigated samples was calculated in Table 1. accompanied with a sharp decrease in crystallinity of
In addition to the previous phenomenon, much Ni as confirmed by XRD diffractograms (Figure 1).
useful information can be extracted by deeply analyz- Moreover, anisotropy was still observed in the fifth
ing the ESR spectra of samples under investigations. use of 20 wt% Ni/Al2O3 catalyst where XRD
Thus from Figures 5 and 6, it can be observed that as diffractograms showed that it still has a crystalline
the amount of loading of Ni increases, the amount of Ni metal (Figure 2).

5% Ni/Al2O3
20% Ni/Al2O3 new

20% Ni/Al2O3 fifth time used

5% Ni/Al2O3 fifth time used

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
Field [G] Field [G]

Figure 8. ESR spectra of 20 wt% Ni/Al2O3 catalyst, freshly Figure 10. ESR spectra of 5 wt% Ni/Al2O3 catalyst, freshly
prepared and after fifth time of using at 1:5 wt:wt of prepared and after fifth time of using at 1:5 wt:wt of
Ni:PNP. Ni:PNP.
 Green Chemistry Letters and Reviews 131

20% Ni/SiO2

20% Ni/SiO2 dil

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 Field [G]
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

Field [G]
Figure 12. ESR spectra of commercial Raney nickel.
Figure 11. ESR spectra of 20 wt% Ni/SiO2 as it is and after
solid
solid dilution with bare SiO2 till anisotropy disap- observable change in the color during the reaction
pears.
from yellow to green to colorless, facilitated the
suggestion of the mechanism of this reaction.
The same observation can be also shown in low
loading samples of 5 wt% Ni (Figures 9 and 10).
In addition, the ESR spectra of commercial Raney Mechanism of hydrogenation
nickel (Figure 12) showed a severe anisotropy, with During the hydrogenation process, the change in
low magnetic field overlapping signals. This behavior color was observed in a sequence of: (1) yellow color
was also confirmed by similar catalytic activity of high of PNP; (2) green color (intermediate A); and then (3)
loading catalyst and Raney nickel (Table 3).
discharge of all color (PAP) accompanied with 100%
conversion.
Discussion The following mechanism showed that H2
Hydrazine was utilized as the hydrogen donor in the (generated from the decomposition of hydrazine
reduction process of PNP over different nano sup- over Ni metal) is added first to the nitro group; after
ported nickel catalysts. The reaction was found to be which, the elimination of two molecules of water was
completed within only a few minutes. In addition, the accompanied by a rearrangement of the molecule
to form the green intermediate (A) (Scheme 1).
The addition of another H2 molecule to the green
Table 1. Particle size of investigated samples using XRD
and ESR.

Particle size (nm) OH O H O

From XRD From ESR Nano Ni/Hydrazine -2H2O

Catalyst diffractograms spectra H2

N N N
20 wt% Ni/SiO2 40 15 O O
H O O
PNP H Green Color
20 wt% Ni/SiO2 Amorphous 11 H H Intermediate (A)
Yellow
(fifth time used)
20 wt% Ni/Al2O3 36 16 H2
20 wt% Ni/Al2O3 36 15
(fifth time used) OH
5 wt% Ni/SiO2 40 19
5 wt% Ni/SiO2 28.94 16
(second time used)
5 wt% Ni/Al2O3 34.30 14 NH2
5 wt% Ni/Al2O3 34.00 13 Discharge in color
(fifth time used) PAP

Commercial Raney
15 Scheme 1. Supposed mechanism for reduction process of

nickel p-nitrophenol.
 132 I.H.A. El Maksod and T.S. Saleh

intermediate is then accompanied by the formation nickel as evidenced by ESR determination of particle
of PAP. size (Table 1).
In addition, the increase of the catalytic activity of
low loading Ni on both SiO2 and Al2O3 supports
Catalytic activity suggests that not all nickel species act as active
Since the end of the reaction was found to be self centers for this reaction. This can be viewed from
indicated by a change in color at 100% conversion, two aspects, first, the increase of nickel loading will
the catalytic activity may be better expressed as the decrease the dispersion of nickel and hence not all
time to reach 100% conversion through this color nickel can be susceptible to the reactants; the second
change. Different ratios of PNP to Ni metal were aspect is that the neighboring nano-sized nickel
varied and the catalytic activity of each was mea- particles can influence each other as evidenced by
sured. Table 2 shows the time to completion for ESR. It was also found that, as the amount of the
reactions with different concentrations of catalyst. existence of such strain among nano-nickel particles
The results indicated that a 5 wt% Ni/Al2O3 is the increases, the number of active nickel species de-
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

best catalyst concentration, with the lower time to creases. Moreover, the catalytic activity was found to
reach 100% conversion at different ratios of Ni:PNP. be proportional only to the crystalline nickel and this
Moreover, in order to completely characterize the leads us to believe that the Al2O3 support is more
catalyst we also studied the durability of the catalysts effective than the SiO2 support where, even at lower
of 1:5 wt:wt Ni:PNP, using the catalyst up to five loading (5 wt%), the catalytic activity and durability
times as shown in Table 3. are still very high.
Deeply analyzing the above data, very useful In addition to all these observations, all catalyst
information regarding the catalytic activity of the samples were higher in catalytic activity than com-
catalysts prepared can be extracted. Thus, the cataly- mercial Raney nickel. Moreover, the supported
tic activity of 5 wt% Ni supported on either SiO2 or catalyst has the advantage of easily handling and
Al2O3 at lower ratios of Ni:PNP (1:5 wt:wt) exhibits a the possibility of reuse of the catalyst more than one
higher activity compared with those of higher loading time, as compared to the impossibility to reuse Raney
of Ni (20 wt%). Moreover, at higher ratios of Ni:PNP nickel where almost all nickel is lost during the
(1:10 and 1:15 wt:wt) the 5 wt% Ni/Al2O3 showed filtration process at this low concentration of nickel.
superior catalytic activity compared to the 5 wt% Ni /
SiO2 support. This can be explained by the ease of
transformation of crystalline nickel into amorphous Experimental
phase over SiO2 due to the weak metal support
Materials
interaction. Moreover, the catalytic activity seems to
be proportional to the crystalline nickel only. This NiSO4.7H2O, Al(OH)3, commercial Raney nickel,
behavior is confirmed during the durability test (Table hydrazine hydrate 80%, PNP, PAP (as a standard
3) where a sharp decrease in the catalytic activity of materials), and methanol (spectroscopic grade) were
20 wt% Ni/SiO2 at the fifth time of successive using purchased from Merck Co., Germany.
(40 min) is accompanied with the disappearance of Commercial silica was obtained from Brownell
crystalline nickel, as shown by XRD diffractograms limited Co., London. X-ray diffractograms were
(Figure 1). In the same manner, the 5 wt% Ni/SiO2 at collected using Bruker D8 advance instrument with
the second time of use also showed the disappearance CuKa1 target operated at 40 kV and 40 mA. ESR
of crystalline nickel (Figure 3). Moreover, this beha- spectra were measured using (Brucker Elexsys. 500)
vior is accompanied by decrease in particle size of operated at X-band frequency. The following para-
meters are generalized to all samples otherwise
Table 2. Effect of concentration of PNP:Ni on the catalytic mentioned in the text: microwave frequency, 9.73
activity. GHz; receiver gain, 20; sweep width, 6000 center at
3480 G; and microwave power, 0.00202637 Watt.
wt:wt ratio of
Ni:PNP

Catalyst 1:5 1:10 1:15 Preparation

Nickel was loaded on Al2O3 (obtained by calcination
20 wt% Ni/SiO2 300 360 489 Time to reach of Al(OH)3 at 5508C for 4 hours) and SiO2 by means
20 wt% Ni/Al2O3 300 390 420 100% conversion
of impregnation method to be 20, 5, and 2.5 wt%.
5 wt% Ni/SiO2 300 420 527 (sec)
Hydrazine hydrate was used to reduce the catalysts in
5 wt% Ni/Al2O3 80 190 200
order to obtain the metallic form of nickel. Solid
solid
 Green Chemistry Letters and Reviews 133
Table 3. Durability of the catalysts after five times of using at concentration of 1:5 wt:wt Ni:PNP.

Number of successive uses of 1:5 wt:wt Ni:PNP

Catalyst 1 2 3 4 5

20 wt% Ni/SiO2 240 240 383 1200 2400 Time to reach

20 wt% Ni/Al2O3 300 300 300 540 780 100% conversion
5 wt% Ni/SiO2 144 2100


(sec)
5 wt% Ni/Al2O3 80 93 100 240 240
Commercial Raney nickel 260

dilution is done by adding bare supports of SiO2 or guided according to the change in color during
Al2O3. the reaction. The change in color in the reaction
makes it a self-indicator of 100% conversion, which
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014

decreases the time and effort for following up

Hydrogenation process the reaction.
The hydrogenation process was performed by dissol-
ving PNP in an appropriate amount of methanol
followed by the addition of hydrazine hydrate as the References
hydrogen source and heating at 808C. The catalyst
(1) Trost, B.M. Science 1991, 254, 1471
1477.
was then added to the heated solution and the time to (2) Sheldon, R.A. Green Chem. 2007, 9, 1273
1283.
reach 100% conversion (as examined by thin layer (3) Rode, C.V.; Vaidya, M.J.; Jaganathan, R.; Chaudhari,
chromatography (TLC) and IR spectra) was taken as R.V. Chem. Eng. Sci. 2001, 56, 1299
1304.
an expression of the catalytic activity. (4) Rode, C.V.; Vaidya, M.J.; Chaudhari, R.V. Org.
The filtrate was then evaporated at reduced Process Res. Dev. 1999, 3, 465
470.
pressure and the residue was recrystallized from hot (5) Komatsu, T.; Hirose, T. Appl. Catal. A: Gen. 2004,
water to give pure product of PAP in almost 100% 276, 95
102.
yield. (6) Sathe, S.S. Process for preparing p-aminophenol in the
The characteristics of the product, PAP, are listed presence of dimethyldodecylamine sulfate. US Patent
below: 4176138, 1979.
(7) Lee, L.T.; Chen, M.H.; Yao, C.N. Process for
IR:(nmax =cm1 ):3423; 3340 (NH2 ); 3190 (OH): manufacturing p-aminophenol. US Patent 4885389,
1989.
1
H NMR DMSO-d6, D (ppm): 5.98 (s, 1H, OH, (8) Yun, K.S.; Cho, B.W. Process for preparing para-
D2O
exchangeable), 6.42 (d, 2H, J6.7 Hz, ArH’s), aminophenol. US Patent 066369, 1991.
6.99 (d, 2H, J6.7 Hz, ArH’s), and 9.86 (br s, 2H, (9) Vaidya, M.J.; Kulkami, S.M.; Chaudhari, R.V. Org.
NH2, D2O
exchangeable). Process Res. Dev. 2003, 7, 202
208.
(10) Venkatraman, K. The Chemistry of Synthetic Dyes;
Academic Press: New York, 1952; Vol. I; p 184.
Conclusion (11) House, H.O. Modern Synthetic Reactions, 2nd ed.;
Benjamin: New York, 1977; p 145.
In this study we found that the use of hydrazine as a (12) Rylander, P.N. Hydrogenation Methods; Academic:
hydrogen source was very effective for the reduction New York, 1985; p 365.
of PNP into PAP. The use of supported nano-sized (13) Popp, F.D.; Schultz, H.P. Chem. Rev. 1962, 62, 19.
nickel was found to be very effective in such (14) Harmon, R.E.; Gupta, S.K.; Brown, D.J. Chem. Rev.
reactions. The catalytic activity reached three times 1972, 72, 21
52.
higher than the commercial Raney nickel in the case (15) Chen, R.Z.; Du, Y.; Chen, C.L.; Xing, W.H.; Xu,
of 5 wt% Ni/Al2O3 catalyst. Of a much higher N.P.; Chen, C.X.; Zhang, Z.L. J. Chem. Ind. Eng.
concern may be the possibility of reuse the supported (China) 2003, 54, 704
706.
catalysts more than one time in the reaction. The (16) Du, Y.; Chen, H.L.; Chen, R.Z.; Xu, N.P. Synthesis of
p-aminophenol from p-nitrophenol over nano-sized
catalytic activity of nickel is influenced by the
nickel catalysts. Appl. Catal. A: Gen. 2004, 277,
existence of strain among nano nickel particles and
259
264.
is proportional to only the crystalline nickel. Ni/ (17) Rautanen, P.A.; Aittamaa, J.R.; Krause, A.O.I. Chem.
Al2O3 catalyst has proved to be more effective than Eng. Sci. 2001, 56, 1247
1253.
Ni/SiO2 catalyst, where high durability and high (18) Suh, D.J.; Park, T.J.; Lee, S.H.; Kim, K.L. J. Non-
catalytic activity of Ni/Al2O3 catalyst were attained. Cryst. Solids 2001, 285, 309
316.
The mechanism of the hydrogenation reaction is (19) Wu, W.H.; Xu, J. Catal. Commun. 2004, 5, 591
595.
 134 I.H.A. El Maksod and T.S. Saleh

(20) Wu, W.H.; Xu, J.; Ohnishi, R. Appl. Catal. B: Environ. (27) Yan, D.; Hongling, C.; Rizhi, C.; Nanping, X. Appl
2005, 60, 129
137. Catal A: Gen. 2004, 277, 259
264.
(21) Kapoor, M.P.; Matsumura, Y. J. Mol. Catal. A: (28) Zhang, F.; Chan, S.W.; Spanier, J.E.; Apak, E.; Jin,
Chem. 2002, 178, 169
172. Q.; Robinson, R.D.; Herman, I.P. Appl. Phys. Lett.
(22) Toppinen, S.; Rantakyh, T.K.; Salmi, T.; Aittamaa, J. 2002, 80, 127
129.
Catal. Today 1997, 38, 23
30. (29) Sharma, V.K.; Baiker, A. J. Chem. Phys. 1981, 75,
(23) Quincoces, C.E.; Gonzfilez, M.G. Kinetic study on 5596
5601.
Coz refroming of methane. Chin. J. Chem. Eng. 2001, (30) Suran, G.; Stankoff, A.; Hofmann, F. Phys. Rev. B.
9, 190
195. 1973, 8, 1109
1118.
(24) Rizhi, C.; Yan, D.U.; Weihong, X.; Nanping, X.U. (31) Kawabata, A. J. Phys. Soc. Jpn. 1970, 29, 902
911.
Chinese J. Chem. Eng. 2006, 14, 665
669. (32) Selim, M.M.; Abd El-Maksoud, I.H. Microporous
(25) Shankare, G.; Channe, G. Tetrahedron 2002, 58, Mesoporous Mater. 2005, 85, 273
278.
2211
2213.
(26) Chang, Y.C.; Chen, D.H. J. Hazard Mater. 2009, 165,
664
669.
Downloaded by [University of Washington Libraries] at 11:15 02 December 2014