Catalytic amination of octanol for synthesis of trioctylamine and catalyst characterization

Article abstract of DOI:10.1007/s10562-011-0686-z

Synthesis of trioctylamine by the amination of octanol and ammonia under atmospheric pressure over an excellent Ni-Cu catalyst supported on diatomite is studied in this article. The key factor for the synthesis is the preparation of catalyst with a high activity and selectivity. The activity and selectivity can be adjusted by varying the Ni to Cu ratios. The optimum molar ratio of Ni to Cu was 1.25:1. For the catalyst with a Ni/Cu ratio of 1.25:1, the conversion of octanol and the selectivity of trioctylamine reached 100 and 97.3%, respectively, at 5 h. The reaction of dioctylamine with octanol was the rate-determining step for the formation of trioctylamine. The Physical properties of catalysts, such as particle size, Brunauer-Emmett-Teller (BET) surface area, valence state of catalyst elements, morphology and reduction properties of catalysts were investigated by using X-ray diffraction, nitrogen adsorption-desorption isotherms (BET), X-ray photoelectron spectroscopy, Transmission electron microscopy, and temperature programmed reduction, respectively. The reaction scheme of catalytic amination of octanol with ammonia was discussed. Graphical Abstract: [Figure not available: see fulltext.][Figure not available: see fulltext.]

Full text of DOI:10.1007/s10562-011-0686-z

Catal Lett (2011) 141:1635–1642
DOI 10.1007/s10562-011-0686-z
Catalytic Amination of Octanol for Synthesis of Trioctylamine
and Catalyst Characterization
Yunling Li
Minghui Zhang
•
Qiuxiao Li
•
Lifei Zhi
•
Received: 26 July 2011 / Accepted: 12 August 2011 / Published online: 23 August 2011
Ó Springer Science+Business Media, LLC 2011
Abstract Synthesis of trioctylamine by the amination of
octanol and ammonia under atmospheric pressure over an
excellent Ni–Cu catalyst supported on diatomite is studied
in this article. The key factor for the synthesis is the
preparation of catalyst with a high activity and selectivity.
The activity and selectivity can be adjusted by varying the
Ni to Cu ratios. The optimum molar ratio of Ni to Cu was
1 Introduction
Long-chain alkyl tertiary amines including mono-, di-, and
tri-alkyl tertiary amines (RNMe , R NMe and R N,
2
2
3
respectively), as important intermediates for cationic sur-
factants, amphoteric compounds and important organic
intermediates, have extensive applications. These deriva-
tives of tertiary amines can be used as detergents, fabric
softener, antistatic agents, bactericides, cosmetic additives
and so forth. Especially, tri-alkyl tertiary amines can be
used as extraction agents to recover various metal ions and
acids from water solutions and as phase transfer catalysts
accelerating the reaction rates of some reactions [1–3].
Catalytic amination of fatty alcohols is a major process for
the preparation of these amines at present. Studies on
catalysts and synthetic processes for mono- and di-alkyl
tertiary amines have been performed for a long time, and
have been reported widely [1, 3–7]. Cu/Ni-based catalysts
show excellent performances for the preparation of mono-
and di-alkyl tertiary amines [8–13]. Performances of Cu–
Ni catalysts can be adjusted by varying Cu/Ni ratios or by
adding a third element. Reported catalysts so far for the
preparation of mono- and di-alkyl tertiary amines contain
more Cu than Ni [3–13]. In Cu-rich-Cu/Ni-based catalysts,
Cu is a main catalyst element, and Ni is an effective pro-
moter. It has long been believed in general that Cu/Ni-
based catalysts with Cu-rich compositions for the effective
1
.25:1. For the catalyst with a Ni/Cu ratio of 1.25:1, the
conversion of octanol and the selectivity of trioctylamine
reached 100 and 97.3%, respectively, at 5 h. The reaction
of dioctylamine with octanol was the rate-determining step
for the formation of trioctylamine. The Physical properties
of catalysts, such as particle size, Brunauer–Emmett–Teller
(
BET) surface area, valence state of catalyst elements,
morphology and reduction properties of catalysts were
investigated by using X-ray diffraction, nitrogen adsorp-
tion–desorption isotherms (BET), X-ray photoelectron
spectroscopy, Transmission electron microscopy, and tem-
perature programmed reduction, respectively. The reaction
scheme of catalytic amination of octanol with ammonia
was discussed.
Keywords Ni/Cu ꢀ Catalytic amination ꢀ Octanol ꢀ
Trioctylamine ꢀ Characterization
amination of fatty alcohols with Me NH are also effective
2
Y. Li (&)
for the amination of fatty alcohols with MeNH and NH ,
2
3
College of Chemistry and Chemical Engineering,
Shanxi University, 34# Wenyuan Str., Taiyuan 030001,
Shanxi, People’s Republic of China
e-mail: lyunl0068@sina.com
and those catalysts with Ni-rich compositions are not
applicable to the synthesis of R NMe [8] and R N [2]. Up
2
3
to now, very few articles were reported about catalysts for
the synthesis of tri-alkyl tertiary amines [2, 14]. Tri-alkyl
tertiary amines contain a bulky group (three long alkyl-
chains) with a steric-hindrance. Therefore, more active
Y. Li ꢀ Q. Li ꢀ L. Zhi ꢀ M. Zhang
China Research Institute of Daily Chemical Industry,
Taiyuan, China
123

1
636
Y. Li et al.
catalysts than those used for the preparation of mono- and
di-alkyl tertiary amines are required.
2.3 Reaction Method
Based on these backgrounds, the present study described
the more effective amination catalysts for the synthesis of
tri-long-alkyl tertiary amines. The catalysts used in the
present study are diatomite-supported Ni–Cu catalysts with
various Ni/Cu ratios. Being different from the reported
catalysts so far for the synthesis of mono- and di-alkyl
tertiary amines, the catalysts used for the synthesis of tri-
alkyl tertiary amines in the present study was Ni-rich new
compositions for Cu/Ni-based catalysts. This difference,
based on a synergism of Cu and Ni, resulted in a significant
increase in activity and selectivity. The excellent results of
our present study opened, for the first time, a new field of
Cu/Ni-based catalysts against the conventional Cu-rich
catalysts. In this paper, characterization of the developed
catalysts was performed in term of particle size, Brunauer–
Emmett–Teller (BET) surface area, valence state of cata-
lyst elements, morphology, and reduction properties by
Transmission electron microscopy (TEM), X-ray diffrac-
tion (XRD), BET, X-ray photoelectron spectroscopy (XPS)
and temperature programmed reduction (TPR) analysis.
The reaction scheme was also discussed.
2.3.1 Reaction apparatus
A four-necked 500-mL round bottom flask equipped with a
stirrer, a thermometer, a gas inlet tube, and a reflux con-
denser with a water separator was used to separate formed
water and an organic phase.
2.3.2 Procedure
Octanol (150 g) and catalyst (2.0 g) were placed into the
flask. H was fed into the reaction system at a flow rate of
2
0.4 L/min under agitation. The temperature of the reactor
was raised to 170 °C and held at the temperature for
40 min for catalyst reduction. Then the mixture of NH
and
3
H
(40%/60%, vol/vol) was fed into the reactor at a rate of
2
0.7 L/min. The condensed water was separated from the
reaction system and organic phase was returned to the
reactor to complete the reaction. The reaction temperature
was raised to 230 °C gradually. Samples for analysis were
taken every hour during the reaction.
2.4 Analysis
2
Experimental
Samples from the amination reaction were analyzed by
GC-HP6890 (J&W GC, USA) gas chromatograph to obtain a
composition of a reaction mixture. Column: DB-1701
2
.1 Materials
(
30 m 9 0.32 mm 9 0.25 lm); column temp.: 80–250 °C
8 °C/min); detector: FID; carrier gas: He 20 mL/min.
Octanol with a purity of[99% was purchased from Beijing
(
Chemical Plant in China. NH with a purity of [99% was
3
purchased from Taiyuan Fertilizer Plant in China. H with
2
a purity of [99.5% was purchased from Taiyuan Steel
Plant in China. Reagent grade of cupric nitrate, nickel
nitrate, and sodium carbonate were purchased from Tianjin
Chemical Plant in China. Diatomite powder was purchased
from Yunnan Aid-Filter Agent Plant in China.
2.5 Catalyst Characterization
TEM grids were prepared by dispersing the fresh calcined
catalysts into redistilled water by ultrasonication and then
placing a drop of the catalyst dispersion into lacey carbon
grids. After evaporation of the water, micrographs were
collected on a JEM-1011 (JEOL Ltd., Japan), with a
2
.2 Catalyst Preparation
200-kV electron source. Several TEM images were recor-
The catalysts were prepared by a conventional co-precipi-
tation method. A calculated amount of diatomite powder
and deionized water were mixed in a beaker and heated to
ded at various locations on the sample and at different
magnifications to confirm that the structures observed were
present throughout the catalyst. For each catalyst repre-
sentative images are presented in the figures.
4
5 °C under agitation. The solutions of Cu–Ni nitrates and
Na CO were simultaneously added dropwise to the slurry.
The XRD data were gathered on a MiniFlex II (Rigaku,
Japan) with monochromatic Cu Ka radiation in the range of
2h = 10–70°. Diffraction patterns were obtained for
selected calcined catalysts. The catalyst powders were
secured onto a glass slide with double-sided sticky tape.
Nitrogen adsorption–desorption isotherms (BET) was
measured using an ASAP 2010 (Micromeritics, USA) at
liquid nitrogen temperature. All samples were degassed at
100 °C under vacuum for 8 h.
2
3
The pH of the slurry had to be maintained at 9 by adjusting
the feed rates of the two solutions. The temperature was
kept at 45 °C for 2 h under agitation. Then, the slurry was
filtered, and the filtered cake was washed with deionized
water until the pH of the washing water becomes neutral
(
pH 7), and then, the washed cake was filtered, dried at
20 °C, calcinated at 450 °C for 3 h, and pulverized to be
used.
1
1
23

Catalytic Amination of Octanol
1637
TPR was performed with an AutoChem2910 (Microm-
ertics, USA). 10% H -Ar gas was fed into the catalyst
2
sample at 25 mL/min, temperature was raised to 550 °C in
1
0 °C/min constantly from room temperature.
XPS spectrum was measured with a V.G. MiltiLab 2000
(
V.G. Analytical, United Kingdom) with Al Ka as the
excitation source. The electron binding energy scale was
calibrated by assigning 284.6 eV to the Cls peak position.
Firstly the catalyst was reduced at 170 °C for 40 min under
H atmosphere, and then XPS was measured.
2
3
Results and Discussion
3
.1 The Activity and Selectivity of Ni–Cu Catalyst
Fig. 2 The time course of the amination reaction of octanol with NH
over the optimized Ni/Cu catalyst supported on diatomite (Ni/Cu
molar ratio, 1.25:1)
3
Seven catalysts with different Ni/Cu molar ratios were
prepared and tested in the amination reaction according to
the methods in Sects. 2.2 and 2.3, respectively. The rela-
tionship between the trioctylamine contents of the samples
and reaction time for each catalyst is shown in Fig. 1. The
trioctylamine content can be taken as a measure of the
catalyst selectivity.
that a synergism of Ni and Cu obviously exists in the
Ni/Cu-based catalysts. The amination of octanol with
ammonia is a consecutive reaction, via the formation of
octylamine and dioctylamine, to form trioctylamine. The
time course of the amination reaction of octanol with NH3
over the optimized Ni/Cu-catalyst (Ni/Cu molar ratio,
1.25:1) is shown in Fig. 2. Various intermediate species
such as octylamine and dioctylamine were observed.
It can be seen from Fig. 2 that only 0.07% of octanol
remained at 4 h, and it disappeared completely at 5 h. The
concentration of unreacted octanol can be taken as a
measure of catalyst activity. These results indicate that the
Ni/Cu-based catalyst with the optimum Ni:Cu ratio of
1.25:1 shows a very high activity. The octylamine content
keeps an extremely low value in the amination reaction,
indicating that octylamine was converted to dioctylamine
very fast, and that this step is not the rate-determining step
for the trioctylamine formation. The formation curve for
the dioctylamine in the figure is typical consecutive reac-
tion in which the content of the intermediate product
It can be seen from Fig. 1 that for the catalysts con-
taining only Cu or only Ni (single element catalysts), the
trioctylamine contents at 5 h were 13.0 and 4.9%, respec-
tively, while for other catalysts with the Ni/Cu ratios, 2:1,
1
9
.5:1 and 1:1, the trioctylamine content at 5 h reach about
2.0%.
The optimum Ni/Cu molar ratio was 1.25:1, and the
trioctylamine content at 5 h was 97.3% (maximum). It was
understood from these observations that coexistence of Ni
and Cu is essential for the generation of effective activities
of the Ni/Cu-based catalysts for the synthesis of R N, and
3
(R NH) showed a maximum value. A similar result for the
2
existence of a primary amine (dodecylamine) in an extre-
mely low concentration was also reported by Abe [2] for
the amination of dodecyl alcohol with ammonia over a
Cu-rich-Cu/Ni-based catalyst with an amination of R NH
2
to R N as a rate-determining step. It was concluded from
3
these observations that the reaction from dioctylamine to
trioctylamine is the rate-determining step of the formation
of trioctylamine.
3.2 Reaction Mechanism
Fig. 1 The dependence of the trioctylamine content on the Ni/Cu
ratio of various diatomite-supported catalysts used in the amination of
octanol and NH
The amination mechanism of alcohols to mono-alkyl
tertiary amines (RNMe ) was reported elsewhere [6–8, 15].
2
3
123

1
638
Y. Li et al.
A simple amination mechanism for alcohols to tri-alkyl
with NH , when NH exist excessively in the reaction
3
3
tertiary amines (R N) was postulated in the article [2].
3
system.
Based on the experimental results of our present studies,
discussion and the reference papers, we proposed a detailed
reaction mechanism for the amination of alcohols to tri-
alkyl tertiary amines, as shown in Scheme 1.
This could be explained from the view point of kinetics:
the reaction between aldehydes and alkylamines is much
faster than that of aldehyde with ammonia, or alkylamines
have a higher adsorption coefficient than ammonia. If
amines are adsorbed more strongly on the catalyst surface,
then the ammonia concentration on the surface should be
low [14, 16, 17].
The amination reaction is composed of ten steps: cata-
lytic dehydrogenation of the alcohol to the alkyl aldehyde
(
1); addition of NH to the formed aldehyde (2); hydrog-
3
enolysis of the NH -aldehyde adduct to form RNH and
3
2
water (3, 4). After RNH is formed, it further reacts with
2
3.3 Catalyst Characterization
alkyl aldehyde to form dialkylamine (5–7). Similarly,
dialkylamine reacts with alkyl aldehyde to form the final
target product, trialkylamine (8–10). From the above
reaction mechanism, it can be thought that an alcohol and
NH3 react to form an alkylamine firstly, and then the
reaction between an alcohol and a formed alkylamine leads
to the formation of dialkylamine, followed by the amina-
tion of an alcohol with dialkylamine to produce
trialkylamine.
3.3.1 TEM Observation
TEM images of diatomite as a catalyst support and three
diatomite-supported catalysts are shown in Fig. 3. It can be
seen from Fig. 3a that the particle sizes of diatomite are
about 40 nm. When the catalyst contains only CuO or NiO,
the particles are about 30 nm (Fig. 3b, c). When both NiO
and CuO are supported on the carrier, it can be seen from
Fig. 3d that the catalyst particle diameters decreased to
about 5–6 nm. CuO and NiO form very fine nanoparticles,
After alkylamine and dialkylamine were produced,
alcohol is aminated with alkylamine or dialkylamine, not
Scheme 1 Proposed reaction
mechanism for the amination of
alcohols and NH
tertiary amines
3
to tri-alkyl
1
23

Catalytic Amination of Octanol
1639
Fig. 3 TEM images of the
carrier and catalysts. a The
carrier diatomite, b Cu catalyst,
c Ni catalyst, and d 1.25:1
Ni–Cu catalyst
resulting in generation of effective performance of the
catalyst for the synthesis of trioctylamine.
and 25–27° (sharp). The NiO catalyst supported on diato-
mite (b) shows three diffraction peaks at 2h = 35–40°,
0–45°, and 60–65° [18]. The CuO catalyst (d) shows two
4
3
.3.2 XRD Measurement
strong and sharp diffraction peaks at 2h = 35–40° [18],
indicating the presence of larger particles of CuO com-
pared to those of NiO. When NiO and CuO are combined
(c), only NiO diffraction peaks are observed and the half
width of the diffraction peaks becomes slightly greater. It
indicates the presence of a higher dispersion of NiO in the
Ni–Cu catalyst (Ni/Cu, 1.25:1). On the other hand, in the
Ni/Cu-based two-component catalyst (c), diffraction peaks
of CuO disappear, which means that CuO is highly dis-
persed on the carrier. These XRD results coincide with the
TEM results.
The XRD patterns of the carrier and three catalysts are
shown in Fig. 4. The diatomite as a catalyst support
(
a) shows two diffraction peaks at 2h = 15–25° (broad)
3.3.3 N Adsorption–Desorption Isotherms
2
N adsorption–desorption isotherm tests were conducted to
2
investigate changes in the pore structures of catalysts. N2
adsorption–desorption isotherms of three catalysts are
shown in Fig. 5. According to the International Union of
Pure and Applied Chemistry (IUPAC) classification [19],
the isotherms showed a typical Type IV model.
The specific surface areas were evaluated using BET
method [20]. Pore size distribution (PSD) was calculated
Fig. 4 XRD patterns of carrier and catalysts. a diatomite, b Ni
catalyst, c 1.25:1 Ni–Cu catalyst, and d Cu catalyst
123

1
640
Y. Li et al.
Fig. 6 TPR of the three catalysts. a Ni catalyst, b Cu catalyst, and
c 1.25:1 Ni–Cu catalyst
2
Fig. 5 N adsorption–desorption isotherms of catalysts
catalyst containing only Ni. The reduction temperature
2
Table 1 N adsorption and desorption data
was 311 °C [21–24]. b shows the reduction process of
Catalyst
(
BET
surface area
Volume
of pores
BJH pore
diameter
˚
(A)
2
?
0
Cu ? Cu of the Cu/diatomite catalyst containing only
Cu. The reduction temperature was 190 °C. These results
indicated that the reduction of Ni is more difficult than
Ni:Cu)
2
m g
-1
3
(cm g
-1
)
(
)
2
?
Diatomite
5.33
0.01
0.12
0.23
0.24
0.29
0.28
0.05
0.06
88.61
72.19
2?
that of Cu . c shows the reduction process of the Ni/Cu
1
2
1
1
1
0
0
:0
57.80
65.59
61.84
72.71
58.48
24.17
15.73
catalyst (Ni/Cu, 1.25:1). The reduction temperature was the
lowest, 170 °C. A decrease in the reduction temperature for
c might be brought about by a strong synergism due to the
coexistence of Ni and Cu.
:1
123.21
141.59
146.03
177.76
86.45
.5:1
.25:1
:1
.5:1
:1
3.3.5 XPS Study
176.46
XPS measurement of seven catalysts with different Ni/Cu
ratios (mol) were performed, and surface compositions (Ni
mol %, Cu mol %) of the catalysts were estimated based on
XPS peak areas of Ni2p3/2 and Cu2p3/2 and sensitivity factors
(Ni, 4.044; Cu, 5.321) by using the following equations [25].
ANi
using the Barrett–Joyner–Halenda (BJH) method [21]
based on the adsorption branch of the isotherm, and
the pore size was estimated from the peak position of the
distribution curve. The pore volume was taken at the
4
ANi
:044
:044
P/P = 0.990 point. The BET surface area, total pore
0
nðNiÞ% ¼
ꢁ 100%
ACu
5:321
þ
4
volume, and pore size are summarized in Table 1.
ACu
As shown in Table 1, the BET surface area and the pore
volume of the 1.25:1 Ni–Cu catalyst became larger com-
pared to those of diatomite and other catalysts. It can be
considered that the larger surface area of the two-compo-
nent catalyst is the one of the factors for the more effective
5
:321
nðCuÞ% ¼
ꢁ 100%
ANi
4
ACu
5:321
þ
:044
As a result, the Ni mol % and Cu mol % of the surface of
the optimum catalyst were 76.2, 23.8%, respectively, and
surface enrichment with Ni was observed on the catalyst
surface. The surface Ni/Cu ratio of the optimum catalyst was
3.2:1, indicating that Ni was easily concentrated on the
catalyst surface. It was concluded from these observations
that a catalyst with a Ni-rich surface composition and a
synergism of Ni and Cu are essential factors for the selective
synthesis of trioctylamine by the stepwise amination of
octanol and ammonia.
amination of octanol with NH due to the higher dispersion
3
of metal nanoparticles on the catalyst surface and a sig-
nificant change in pore structure of diatomite.
3
.3.4 TPR Test
TPR of the three catalysts (Cu, Ni, 1.25:1Ni–Cu) were
carried out to investigate reduction temperatures of them,
and the results are shown in Fig. 6. In the figure, a shows
Deconvolution (peak separation with curve fitting based
on Gauss–Lorentz distribution (GL % = 80%)) of the XPS
2
?
0
the reduction process of Ni ? Ni of the Ni/diatomite
1
23

Catalytic Amination of Octanol
1641
Fig. 7 Peak separation of the
XPS Cu 2P3/2 and Ni 2P3/2
spectra of the optimum catalyst
(
Ni/Cu, 1.25:1)
peaks of Cu 2P3/2 and Ni 2P3/2 of the optimum catalyst (Ni/
that the amination of octanol with dioctylamine is the rate-
determining step for the formation of trioctylamine, which
is the same result reported by Abe on the amination of
dodecyl alcohol with ammonia to tridodeylamine over a
Cu-rich-Cu/Ni-based solid catalyst.
Cu ratio, 1.25:1), which was reduced with H at 170 °C for
2
4
0 min, was performed, and the result is shown in Fig. 7.
0
In the left figure, peak 0 and peak 1 indicate Cu and
2
?
0
Cu , respectively. In the right figure, peak 0 indicates Ni ,
and peaks 1, 2 and 3 indicate the main peak, shoulder peak
The catalyst with a Ni–Cu molar ratio of 1.25:1 is the
optimum for this amination reaction. Characterization of
the diatomite-supported Ni/Cu catalysts were performed in
terms of the valence states and reduction properties of
catalyst elements (Ni, Cu), particle size, and catalyst
morphology by using TEM, XRD, XPS, BET and TPR.
It was concluded that a Ni-rich surface composition (Ni,
76.2 mol %; Cu, 23.8 mol %) and coexistence of Ni and Cu
are the essential factors for the effective and selective syn-
thesis of trioctylamine by the amination of octanol and
ammonia over the diatomite-supported Ni/Cu-based
catalysts.
2
and shake-up peaks of Ni , respectively.
?
The relative area of peak 0 to the total area of the four
peaks can be taken as the reduction degree of Cu or Ni. It
can be seen from the figure that reduction of Cu and Ni of
the optimum catalyst was not completed.
0
0
The contents of Cu and Ni were 69.7 and 9.3%,
respectively. This result indicates that most Cu was existed
0
2?
as Cu , and most Ni was existed as Ni on the catalyst
surface.
These results on the reduction degrees of copper and
nickel of the Cu/Ni-based two-component solid catalyst are
similar to those of reported Cu/Ni-based catalysts so far
It was also concluded that some activation (increases in
BET surface area and pore diameter) of catalysts induced
by the loading of Ni and Cu is another factor for the
increased activity and selectivity of the optimum catalyst.
[
1, 4, 5, 9]. Best of our knowledge, detailed study to
investigate the relationship between the reduction degree of
copper and the activity of Cu/Ni-based two component
catalysts used for the amination reaction has not been
reported so far. However, importance of the existence of
Acknowledgments The authors would like to thank China Research
Institute of Daily Chemical Industry for fund support and the publi-
cation of the present study.
2
?
3?
high valence state of nickel such as Ni , and Ni for the
prevention of the disproportionation of formed amines and
0
the effect of the reduced nickel (Ni ) on the promotion of
the disproportionation of amines are reported [1, 4, 5, 9].
References
4
Conclusions
1. Li QX, Zhang GY, Peng SY (2002) J Surfactants Deterg 5:229
2
3
4
5
. Abe H, Taniguchi H, Okabe K, Sotoya K (1989) Yushi 38:565
. Kimura H, Taniguchi H (2005) Appl Catal A 287:191
. Li QX, Zhang GY, Peng SY (2001) Chin J Catal 22:7
. Li QX, Zhang GY, Peng SY (2001) Chin J Appl Chem 18:693
Trioctylamine was synthesized by the reaction of octanol
and ammonia over Ni-rich Ni/Cu catalysts supported on
diatomite under atmospheric pressure. It was confirmed
6. Okibe K, Abe H, Yokota Y (1989) Stud Surf Sci Catal 44:299
123

1
642
Y. Li et al.
7
. Baiker A, Caprez W, Hoistein W (1983) Ind Eng Chem Prod Res
Dev 22:217
19. Tak-Hyun K, Min J, Jae Kwang
Mesoporous Mater 108:22
P
(2008) Microporous
8
9
. Abe H, Hashiba K, Yokota Y, Okabe K (1988) Yushi 37:519
. Li QX, Zhang GY, Peng SY (2003) Fine Chem 32:151
20. Brunauer S, Emmett PH, Teller E (1938) J Am Chem Soc 60:309
21. Barrett EP, Joyner LG, Halenda PP (1951) J Am Chem Soc 73:
373
22. Abe H, Hoshi S, Domen K et al (1990) Chem Lett 19:401
23. Wang QW, Yang JL, Ren JF et al (1990) Catal Lett 4:63
24. Robertson SD, Mc Nicol BD, De Baas JH et al (1975) J Catal
37:424
25. Li QX (2003) Institute of Coal Chemistry, Chinese Academy of
Sciences as a requirement for admission to the degree of Ph.D.,
pp 44–45
1
1
1
1
1
1
1
1
0. Kimura H, Matsutani K, Tsutsumi S (2005) Catal Lett 99:119
1. Abe H et al (1989) J Jpn Oil Chem Sci 38:94
2. Li QX et al (1999) China Surfactant Deterg Cosmet 2:33
3. Kimura H et al (2005) Catal Lett 99:133
4. Tlusty T, Pasek J, Vonka P (2006) React Kinet Catal Lett 88:371
5. Kimura H, Tsutsumi S, Tsukada K (2005) Appl Catal A 292:281
6. Fischer A, Mallat T, Baiker A (1997) Catal Today 37:167
7. Yamakawa T, Tsuchiya I, Mitsuzuka D, Ogawa T (2004) Catal
Commun 5:291
1
8. Cangiano M De los A, Ojeda MW, Carreras AC, et al (2010)
Mater Character 61:1135
1
23