Physicochemical and Catalytic Properties of Ni,H/ZSM-5 and Ni,H/ZSM-5–Binder Catalysts Prepared in the Absence and in the Presence of Binder

Article abstract of DOI:10.1134/S0023158419060077

Physicochemical and catalytic properties of H/ZSM-5 and Ni,H/ZSM-5 along with Ni,H/ZSM-5–Al₂O₃ (1 : 1) systems were examined. The systems with a binder were prepared by two different methods of mixing zeolite with aluminum hydroxide. The samples were characterized by N₂ sorption (at 77 K), X-ray diffraction, ²⁷Al magic-angle spinning (MAS) NMR spectroscopy, temperature-programmed desorption of ammonia and adsorption of pyridine. Preparation of the zeolite catalyst with aluminium hydroxide was made by two methods: (1) mixing of powders and (2) combining appropriate pastes. Regardless of the method used for mixing there was no blocking of zeolite channels by aluminum oxide. The method of mixing zeolite with aluminium hydroxide powders promotes migration of aluminum from aluminum hydroxide/oxide to the zeolite framework. The results of n-hexane conversion showed that with Ni,H/ZSM-5 a slightly lower conversion than with H/ZSM-5 catalyst was observed that can be explained by a reduced yield of cracking products. Ni,H/ZSM-5–Al₂O₃ (1 : 1) catalytic systems were insignificantly less efficient in n-hexane transformation than alumina free samples but at the same time they were less selective towards hydrocarbons with boiling temperatures higher than this of n-hexane, precursors of carbonaceous deposits.

Full text of DOI:10.1134/S0023158419060077

ISSN 0023-1584, Kinetics and Catalysis, 2019, Vol. 60, No. 6, pp. 851–861. © Pleiades Publishing, Ltd., 2019.
Physicochemical and Catalytic Properties of Ni,H/ZSM-5
and Ni,H/ZSM-5–Binder Catalysts Prepared in the Absence
and in the Presence of Binder
a
a,
a
A. Masalska , K. Jaroszewska *, and J. R. Grzechowiak
a
Wrocław University of Science and Technology, Faculty of Chemistry, Wrocław, 50-344 Poland
e-mail: karolina.jaroszewska@pwr.edu.pl
Received January 26, 2019; revised May 31, 2019; accepted July 2, 2019
*
Physicochemical and catalytic properties of H/ZSM-5 and Ni,H/ZSM-5 along with Ni,H/ZSM-5–Al O
2
3
(
1 : 1) systems were examined. The systems with a binder were prepared by two different methods of mixing
zeolite with aluminum hydroxide. The samples were characterized by N sorption (at 77 K), X-ray diffrac-
2
27
tion, Al magic-angle spinning (MAS) NMR spectroscopy, temperature-programmed desorption of ammo-
nia and adsorption of pyridine. Preparation of the zeolite catalyst with aluminium hydroxide was made by two
methods: (1) mixing of powders and (2) combining appropriate pastes. Regardless of the method used for
mixing there was no blocking of zeolite channels by aluminum oxide. The method of mixing zeolite with alu-
minium hydroxide powders promotes migration of aluminum from aluminum hydroxide/oxide to the zeolite
framework. The results of n-hexane conversion showed that with Ni,H/ZSM-5 a slightly lower conversion
than with H/ZSM-5 catalyst was observed that can be explained by a reduced yield of cracking products.
Ni,H/ZSM-5–Al O (1 : 1) catalytic systems were insignificantly less efficient in n-hexane transformation
2
3
than alumina free samples but at the same time they were less selective towards hydrocarbons with boiling
temperatures higher than this of n-hexane, precursors of carbonaceous deposits.
Keywords: H/ZSM-5 and Ni,H/ZSM-5 zeolites, binder, aluminum hydroxide, n-hexane, N sorption, XRD,
2
27
Al MAS NMR, aluminum migration
DOI: 10.1134/S0023158419060077
aromatic hydrocarbon together with reduced oxygen-
ate breakthrough during biomass pyrolysis [4].
Nickel catalysts containing zeolites constitute a
group of heterogeneous catalysts, which may play an
important part in the refinery industry. There is cur-
rently a great interest in acid-catalyzed dewaxing by
hydrocracking–hydroisomerization of n-paraffins [1].
Roncolatto et al. [2] have patented the Ni/ZSM-5 cat-
alyst for fluid catalytic cracking (FCC) process, which
Zeolites are usually synthesized in the Na-form
and as powders. To modify their surface properties,
use can be made of ion exchange (for proton or transi-
tion metal), which leads, inter alia, to the generation of
acid sites on their surface. In contrast to X- and Y-zeo-
lites, the frameworks of which is unstable in acid
media, the exchange of the sodium ions in the
Na/ZSM-5 zeolite for the protons (H/ZSM-5) can be
carried out by direct acid treatment. According to
investigations reported by Inui et al. [5] ion exchange
in Na/ZSM-5 with HCl, HNO , H SO (1–2 M solu-
is capable of the NO reduction during the regenera-
x
tion stage. It has been also revealed that Ni/ZSM-5
catalytic system displays an extraordinary activity for
the complete hydrogenation of polymethylbenzenes
[
3]. Recently, Yung et al. has found that the Ni/ZSM-5
catalysts with a high stability showed high yields of
3
2
4
tions) produces some dealumination (<10%). Metals
Abbreviations: HZ—H/ZSM-5 zeolites, NH –TPD—tempera-
3
ture-programmed desorption of ammonia, Py–IR—IR-spec- are generally introduced into the zeolites by ion
troscopy of pyridine adsorption, XRD—X-ray diffraction,
exchange [6–11] but they can also be incorporated by
SEM—scanning electron microscopy, n-C —n-hexane, MAS
6
impregnation [12–14] or anchored at the stage of zeo-
lite synthesis [15]. When incorporation of Ni into
NMR—magic-angle spinning in solid-state NMR spectroscopy,
HZ —HZ zeolites treated with NH Cl, HZ —HZ zeolites
s
4
a
treated with HCl, NiZ and NiZ —Ni,H/ZSM-5 zeolites Na/ZSM-5 support involves the ion exchange tech-
s
a
+
treated with NH Cl and HCl, respectively, PyH —Brønsted
4
nique, the final catalyst displays a strong metal-sup-
port interaction and consequently a high degree of
metal dispersion. In such case, the metal sites per se
can be strongly modified by the support and, on the
acid sites, PyL—Lewis acid sites, W, M and S—weak, medium
and strong acid sites, respectively, DeCYC—dehydrocycliza-
tion, HBH—high boiling hydrocarbons, BTX—benzene, tolu-
ene and xylenes.
851

8
52
MASALSKA et al.
other hand, they can modify the acid sites of the zeo- nium ion (dimerization), followed by its isomerization
lite [16].
In order to utilize zeolite crystals commercially
and cracking (β-scission) [37–39]. The existence of
the reactions governed by the monomolecular or
bimolecular mechanism depends on the length of the
alkene chain but also on the physicochemical proper-
ties of the catalyst [40].
they usually are bonded into pellets with a proper
shape, granulation and mechanical strength [17, 18].
Thus, zeolite powders are shaped in the desired form
of the finished products as a pellet using binders such
as alumina, silica or aluminosilicates (20–90 wt %).
The interaction between the binder and the zeolite can
significantly affect the texture and surface properties
of the final catalytic system [19–22]. Texture and sur-
face properties of systems composed of zeolite and
binder depend not only on the type of the zeolite used
In this work an attempt is made to examine how the
modification of the Na/ZSM-5 zeolite (H/ZSM-5,
Ni,H/ZSM-5) and the method of combining zeolite
with aluminium hydroxide (converted into alumina by
calcination) affects the structure, aluminum distribu-
tion and acidity of zeolites and Ni,H/ZSM-5–Al O
2
3
(
1 : 1) systems. In order to clarify the influence of
physicochemical properties of the resulting composite
catalysts on their catalytic performance, the conver-
sion of n-hexane was used as a model reaction.
[
23–25], but also on the quantity [26, 27] and the type
of the binder [28–31]. Analysis of catalyst texture [23, 24]
shows that in binder-containing systems the quantity of
meso- and macropores promoting a faster diffusion of
molecules increases. The type of the binder significantly
affects the acidity of the zeolite. The use of natural clay
EXPERIMENTAL
Preparation Methods
+
characterized by a high Na content such as kaolin [29],
montmorillonite [20] or bentonite [23, 24, 30] reduces
ZSM-5 zeolites. H/ZSM-5 zeolites (HZ) were
obtained by a twofold ion exchange of Na/ZSM-5
zeolite acidity as a result of ion exchange between the
+
zeolite protons and Na cations. Such an exchange (SiO /Al O = 35, 1.75 wt % Na) in a 1 M solution of
2
2
3
occurs during calcination of the zeolite-binder system
ion exchange in solid phase). Contrary to what is
NH Cl salt (HZ ) or a 0.5 M solution of HCl acid
4
s
(
(
HZ ) at 90°C for 2 h. Ni,H/ZSM-5 zeolites (NiZ ,
a s
NiZ ) were prepared by a twofold ion exchange of the
observed with natural clay, the use of alumina as a
binder accounts for the increase in the acidity of the
zeolite-binder system. This is to be attributed to the
migration of aluminium from alumina to the zeolite.
Extra-framework aluminum (EFAL) can be a source
a
H-form zeolite (HZ or HZ ) in a 0.5 M solution of
Ni(NO ) at 90°C for 2 h.
s
a
3
2
Ni,H/ZSM-5–Al
O
2
systems. Ni,H/ZSM-5–
3
of new Lewis acid sites [32]. Acid sites can also be gen- Al O (1 : 1) systems were prepared by two methods.
2
3
erated during calcination due to the substitution of
Method E (index E) involved mixing of two pastes
+3
+4
Al for framework Si . The occurrence of the syner-
gistic effect between EFAL and Brønsted acid sites can
increase the strength of acid sites [23].
obtained separately: zeolite with 1% HNO and pepti-
3
sate of aluminum hydroxide with 1% HNO (con-
3
verted into alumina by calcination).
Zeolite containing catalysts play an important role
In method A (index A), use was made of a mixture
in n-paraffins transformation (hydroisomerization, of zeolite and aluminium hydroxide powders, which
hydrocracking, dewaxing). Conversion of alkanes over was subjected to aging in water, followed by peptisa-
monofunctional acid catalysts and over bifunctional tion (1% HNO ). Extrudates were calcined at 480°C
3
(
metal/acid) systems is described by different mecha-
for 3 h.
Aluminium hydroxide was obtained by co-precipi-
tation of sodium aluminate and nitric acid at pH 9 and
nisms. When the transformation of alkanes takes place
on the Brønsted acid sites, three reaction mechanisms
are suggested, i.e. (1) classical bimolecular (taking into
account H-transfer, via a tricoordinated carbenium
ions), (2) Haag–Dessau monomolecular protolytic
cracking (via a non-classical, penta-coordinated car-
bonium ion), and (3) oligomeric (with the participa-
tion of alkylation reactions) [33–36]. When the reac-
tion of alkanes occurs in the presence of bifunctional
7
0°C. The final pH value of hydrogel (7) was achieved
by addition of nitric acid. The hydrogel was washed
until wash-water was entirely free of ions in and then
dried in air at 110°C for 12 h. The samples used in this
study are specified in Table 1.
(
metal/acid) catalysts, two mechanisms are consid-
Sample Characterisation
ered. The first, classical monomolecular mechanism,
involves alkane-to-alkene/alkene-to-alkane dehydro-
genation–hydrogenation on a metal site, the forma-
tion of the alkylcarbenium ion transition state on the
Brønsted acid site, followed by its isomerization
and/or β-cleavage. The second bimolecular mecha-
nism (dimerization–cracking) additionally involves
Pore structure. N adsorption was measured at
2
7
7 K with a Quantachrome Autosorb automated gas
sorption system (USA). Before measurements, the
samples were outgassed under vacuum conditions at
50°C for at least 6 h.
1
Acidity. Acidity was determined by the tempera-
the reaction of alkene with the adsorbed tertiary carbe- ture-programmed desorption of ammonia (NH -
3
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2019

PHYSICOCHEMICAL AND CATALYTIC PROPERTIES
853
Table 1. List of the catalysts tested
Method of combining zeolite
and binder
+
+
Code
Composition
Exchange of Na for H using
NaZ
HZs
HZa
NiZs
Niza
Na/ZSM-5
H/ZSM-5
–
–
–
NH Cl
4
H/ZSM-5
HC1
–
Ni,H/ZSM-5
NH Cl
–
4
Ni,H/ZSM-5
HC1
–
(
(
(
NiZ –Al O )
(Ni,H/ZSM-5 + Al O )
NH Cl
Combination of pastes, E*
Blend of powders, A**
Blend of powders, A**
s
2
3 E
2
3 E
4
NiZ –Al O )
(Ni,H/ZSM-5 + Al O )
NH Cl
s
2
3 A
2
3 A
4
NiZ –Al O )
(Ni,H/ZSM-5 + Al O )
2 3 A
HCl
a
2
3 A
*
Method E. Two pastes prepared separately are combined: Ni,H/ZSM-5 zeolite with 1% HNO and aluminium hydroxide peptisate
3
(
obtained with 1% HNO ).
3
*
* Method A. Powders of aluminium hydroxide and zeolite were mixed in an aqueous solution for 4 h, thereafter dried and shaped using
% HNO .
1
3
27
TPD) and by adsorption of pyridine (Py–IR). When ppm with respect to the chemical shift of Al nuclei
use was made of the NH -TPD method, acidity and (δ = 0.00 ppm) in Al O .
3
2
3
acid strength distribution were evaluated in a through-
flow system using a thermal conductivity detector.
Prior to acidity measurements via pyridine (Py)
chemisorption, the samples were activated at 530°C
Catalytic Activity Tests
Catalytic activity was performed in the conversion
for 1 h. Adsorption was carried out at 170°C and excess of n-hexane (n-C ). The kinetic diameter of n-C is
6
6
of pyridine was introduced into the cell. IR spectra
were recorded at room temperature with a Bruker 48
PC spectrometer (Germany) equipped with an MCT
such that n-hexane molecules can enter the channels
of the ZSM-5 zeolite without steric hindrances. In
addition, the presence of six atoms in the chain of n-C
6
(
HgCdTe) detector. Acid site concentrations were
accounts for the occurrence of a number of reactions
that involves not only isomerization and cracking, but
also dehydrocyclization and aromatization. Activity
measurements were conducted in a continuous-flow sys-
determined using the Py absorption bands of 1450 and
–1
1
545 cm for Lewis sites and Brønsted sites, respectively.
Integrated absorbance of each band was achieved using
the suitable software and the calculation of the adequate
acid sites number has been established using molar
tem with fixed-bed reactor (i.d. = 8.0 mm) with n-C sat-
6
urated hydrogen flow (99.8%) under following condi-
extinction coefficients of ε ≈ 1.8 cm/μmol and ε
≈
3
3
1
545
1450
tions: 225–375°C, H : CH = 7 : 1 (Nm /m ) and LHSV =
2
1
.5 cm/μmol reported by Emeis [41], respectively.
–1
1
h . Prior to each catalytic test procedure, the catalysts
3
X-ray diffraction (XRD) measurements. XRD pat- (3 cm , 0.50–0.75 mm) were activated with hydrogen
terns were obtained with a PANalytical X’Pert Pro (450°C for 3 h). Reaction products were analysed by the
MPD diffractometer (Nederland) coupled to a GC method using the RTX-1 capillary column (100%
PW3050/65 high-resolution goniometer at 40 kV and dimethylpolysiloxane, 60 m × 0.25 μm)
3
0 mA (CuKα-radiation). Data were collected over
o
ο
the 2θ range of 5 to 90° with a step size of 0.0167 and
a 25.8-s time per step. The diffractograms were com-
pared with JCPDX references for identification pur-
poses.
RESULTS AND DISCUSSION
To elucidate how the ion-exchange method and
technique of zeolite forming with binder affect the tex-
tural properties of catalysts low-temperature N sorp-
2
Surface morphology. Scanning electron micros-
copy (SEM) was performed using a JSM-5800LV
microscope (JEOL, Japan) with ISIS300 system for
microanalysis (Oxford, USA). Micrographs were
obtained at 20 kV.
tion measurements were carried out. Corresponding
N adsorption–desorption isotherms are plotted in
2
Fig. 1. For NiZ a type I isotherm (according to
s
IUPAC) is obtained, which is typical of microporous
materials. The isotherm for NiZ is different: an
a
Magic-angle spinning in solid-state NMR spectro- increase in N absorbed with increasing p/p values is
2
0
27
scopic (MAS NM) measurements. Al MAS NMR observed with a small hysteresis loop. In the case of
spectra were recorded at 9.4 T with a Bruker Avance alumina, a resulting isotherm was found to possess the
III 400 spectrometer using 4 mm rotors and a spinning hysteresis loop characteristic of type IV and associated
rate of 10 kHz. The chemical shifts are expressed in with capillary condensation in mesopores. The shape
KINETICS AND CATALYSIS Vol. 60 No. 6 2019

8
54
MASALSKA et al.
3
Texture parameters of the studied samples are
given in Table 2. In the parent Na/ZSM-5 zeolite
Volume of N adsorbed, cm
/g
STP
2
3
micropores with a volume (V
) of 0.18-cm /g
micro
account for 85% of the total pore volume (V ). The
total
results indicate that procedure of ion exchange with
NH Cl does not produce significant changes in the
4
zeolite porous structure since values of V and V
total
micro
for Na/ZSM-5 and those found for H/ZSM-5 pre-
pared with NH Cl (i.e. HZ sample) are similar. In the
4
3
4
S
case of HZ sample, more than 80% of the total pore
S
volume is accounted for by micropores. Although
ZSM-5 is acid proof sieve, the ion exchange with HCl
2
produces insignificant changes in the texture of HZ
a
zeolite. A slightly larger V
observed for HZ may
a
total
suggest that the walls between the micropores under-
went partial destruction, which induced formation of
mesopores. In this case, the micropore volume makes
up about 61% of the total pore volume. Nevertheless,
as it can be inferred from the XRD patterns, the
destruction is insignificant, because the intensities of
diffraction maxima typical of ZSM-5 are identical for
HZ and HZ (results not shown).
s
a
With both Ni modified samples, the incorporation
of nickel via ion exchange reduces slightly V with a
micro
1
concomitant decrease of micropore volume by about
4
%. This can be explained by the presence of some Ni
0
0.2
0.4
0.6
0.8
1.0
species in zeolite pores [42]. However, it should be
also noted that when the parent zeolite was exchanged
with salt solution, accommodation of Ni produced the
Relative pressure (p/p0)
Fig. 1. Nitrogen adsorption–desorption isotherms for:
1) Al O , (2) NiZ , (3) NiZ and (4) (NiZ –Al O ) .
NiZ material, in which the contribution of micropo-
res into space volume was nevertheless still high
(
s
2
3
s
a
s
2 3 A
(
79%). It indicates that the effect of the applied proce-
of the isotherms is similar for all NiZ–Al O systems:
2
3
dure on the zeolite crystallinity was insignificant. Fur-
at low p/p values the plot is characteristic of microp-
0
ther evidence in favour of the persistent zeolite crystal-
orous materials, whereas at higher p/p values it is typ- linity in NiZ sample is provided by the XRD pattern
0
s
ical of alumina.
(Fig. 2a). The presented diffractogram shows well
Table 2. Texture of zeolites, zeolite–Al O systems and alumina
2
3
3
3
2
Sample
Vtotal*, cm /g
Vmicro, cm /g
SBET, m /g
dBJH, nm
NaZ
HZs
hza
0.213
0.209
0.276
0.206
0.278
0.590
0.372
0.388
0.398
0.364
0.434
0.182
0.172
0.167
0.163
0.157
–
–
–
–
–
–
–
NiZs
NiZa
Al O
–
–
–
–
251
297
310
–
6.6
6.5
4.9
–
2
3
(
(
(
(
(
NiZ –Al O )
0.083
0.082
0.082
0.078
0.079
s
2
3 E
NiZ –Al O )
3 A
s
2
NiZ –Al O )
3 theor
**
**
s
2
NiZ –Al O )
3 A
275
–
5.6
–
a
2
NiZ –Al O )
3 theor
a
2
*
Total pore volume determined at p/p = 0.99.
0
*
* Theoretical data calculated based on the proportion of components in binary systems.
KINETICS AND CATALYSIS
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PHYSICOCHEMICAL AND CATALYTIC PROPERTIES
a)
65.5 54.0
855
(
6.5
Intensity
(b)
6
5
0.2 μm
4
3
2
1
5
10
15
20
25
30
35
40
2
θ, deg
Fig. 2. Characterisation of NiZ zeolite: (a) XRD pattern
150
100
50
0
–50
–100
δ, ppm
s
and (b) SEM image.
crystallized material corresponding to the structure of
ZSM-5 (JCPDF no. 37-0359) [43]. These results were
also confirmed by SEM micrograph (Fig. 2b), which
2
7
Fig. 3. Al MAS NMR spectra for: (1) Al O , (2) NiZ ,
2
3
s
(
3) NiZ , (4) (NiZ –Al O ) , (5) (NiZ –Al O ) and (6)
a s 2 3 E s 2 3 A
(
NiZ –Al O ) .
a
2
3 A
indicated that NiZ sample displays a well-defined
s
cube-shaped crystals characteristic of ZSM-5 mor-
phology.
trum of Al
O
3
(Fig. 3, 1) is characterised with two res-
2
onance signals at the chemical shifts of 65.5 and
Table 2 shows that when Ni modified ZSM-5 sam-
ples underwent the extrusion procedure with alumina
6
.5 ppm corresponding with aluminum occurring in
the tetrahedral (four-coordinated Al) structure and
octahedral structure (six-coordinated Al), respectively
V
micro
values decreased whereas those of V
total
increased. This is a result of dilution of Ni,H/ZSM-5
samples with alumina that raised the fraction of mes-
opores in the catalyst. Regardless of the method used to
[
(
44]. The signal at 54 ppm observed in zeolite spectra
Fig. 3, 2 and 3) may be assigned to tetrahedrally coor-
dinated framework aluminum (FAL) [45, 46]. The
combine NiZ zeolite with alumina, the contribution of
s
spectrum of NiZ (Fig. 3, 3), the hydrogen form of
a
micropores in the (NiZ –Al O ) and (NiZ –Al O )
s
2
3 E
s
2
3 A
which was obtained with HCl, is characterised addi-
tionally by a weak signal (1.5%) at 0 ppm, characteris-
tic of octahedrally coordinated extra-framework alu-
minum (EFAL) [47, 48]. This effect is absent in the
pelleted systems was 57% lower than in the NiZ sam-
s
ple. The V
value for both extruded samples was
micro
3
found to be 0.08 cm /g indicating that the micropores
account for approximately 21% of the total pore sys-
spectra of NiZ , the protonated form of which was
s
tem. On the other hand, the preparation of (NiZ –
a
27
obtained with NH Cl. The Al MAS NMR spectra of
4
Al O ) system is accompanied by ca. 35% decrease in
2
3 A
zeolite–Al O systems (Fig. 3, 4–6) display signals
2
3
the V
value. Experimentally found V
values for
micro
micro
due to six-coordinated aluminum present in Al O (at
2
3
samples denoted in Table 2 as (NiZ –Al O ) and
3 total
s
2
6
.5 ppm), as well as overlapping signals due to tetrahe-
(
NiZ –Al O ) are as high as the expected parame-
a 2 3 total
drally coordinated aluminum present both in Al O (at
2
3
ters calculated on the basis of the proportion of the
support components regardless of the extrusion
method. This is an indication that the zeolite channels
6
5.5 ppm) and in ZSM-5 (at 54.0 ppm).
Table 3 shows the proportion of aluminum at
are not blocked by alumina. The absence of the hin- 54 ppm in binary systems calculated by deducting the
dering effect was observed by De Lucas et al. [24], who overlapping signals associated with Al O at 65.5 ppm.
2
3
prepared systems composed of 65% bentonite and The area for the signal at 65.5 ppm was computed by
3
5% ZSM-5 by mixing both the components in an considering the signal at 6.5 ppm and taking into
aqueous solution, as well as by Zhang et al. [27], who account that the ratio of the area of the peak at
combined ZSM-5 and alumina (20%) by pelleting a 6.5 ppm (S
) to the area of the peak at 65.5 ppm
6.5ppm
mixture of powders.
Figure 3 shows the 27Al MAS NMR spectra of (NiZ
Al O , zeolites and zeolite–Al O systems. The spec- contains more FAL (S
(
S
) in Al O was 2.75. It was found that the
5.5ppm 2 3
6
–Al O )
2 3 A
system prepared by mixing powders
) than does (NiZ –Al O )
3 E
s
2
3
2
3
54ppm
s
2
KINETICS AND CATALYSIS Vol. 60 No. 6 2019

8
56
MASALSKA et al.
Table 3. Effect of the preparation method of the zeolite–Al O system on the NMR signal area corresponding to the chem-
2
3
27
ical shift for Al
Areas of corresponding peak, a.u.
65.5 ppm
Sample
S6.5ppm/S65.5ppm
6.5 ppm
54 ppm
Al O
9.89
11.0
3.60
–
2.75
2.75
2.75
2
3
(NiZ –Al O )
3 E
4.00*
3.43*
0.41*
0.81**
s
2
(NiZ –Al O )
3 A
9.45
s
2
*
Calculated from S6
5
= S
/2.75.
5.5ppm
6.5ppm
*
* S
= total peak area related to the chemical shift from 100 to 30 ppm minus peak area at 65.5 ppm.
4ppm
system obtained by combining two pastes. This is spectrum of powdered Na/ZSM-5 sample (Fig. 4, 1)
–
1
attributable to migration of aluminum from Al O to the bands at 1443 and 1598 cm [51] are observed
2
3
zeolite framework during calcination of the binary sys- ascribable to the vibrations of pyridine bounded to
+
tem, the components of which underwent stronger Na ions. In addition, a small band at approximately
mixing. A similar effect of migration of aluminum at 1545 cm– [52] can be recognized assignable to pyri-
1
+
the stage of preparation was observed by Fougerit et al. dine coordinated to few Brønsted acid sites (PyH ),
[
[
49] for systems containing mordenite, by Shen et al. which are probably resulted from hydrolysis [53]. The
–1
50] during post-synthesis alumination of mesoporous band at a frequency of 1490 cm corresponds to the
materials (MCM-41), as well as by Zhang et al. [27] vibrations of pyridine chemisorbed either on Lewis or
+
during preparation of ZSM-5 containing systems.
on Brønsted acid sites [54]. Ion exchange of Na with
+
H (Fig. 4, 2 and 3) leads to the generation of the
The Py–IR spectra for all samples examined after
Brønsted acid sites as evidenced by the appearance of
evacuation at 170°C are shown in Fig. 4. In the Py–IR
–1
absorption bands at 1545 and 1635 cm . An insignifi-
cant increase in the concentration of Lewis acid sites
(
PyL) over the surface of HZ and HZ samples can be
s a
Absorbance
also detected by appearance of the absorption bands at
–1
1
450 and 1610–1635 cm .
Py–IR measurements has also shown that the par-
2+
tial ion exchange of protons with Ni ions within zeo-
lite lattice leads to decreasing intensity of the absorp-
–1
tion band at 1545 cm which is characteristic of pyri-
dinium ions formed by chemisorption of pyridine on
+
1
2
PyH (Fig. 4, 4 and 5). The intensity of this band
detected for Ni,H/ZSM-5 sample treated with NH Cl
4
(
Fig. 4, 5) is slightly stronger than that observed for
HCl treated Ni,H/ZSM-5 sample (Fig. 4, 6). These
findings are in agreement with the expected concen-
trations of acid sites (Table 4). The comparison of the
Py–IR spectra registered for Ni,H/ZSM-5 samples
with those observed for Ni,H/ZSM-5–Al O com-
3
4
2
3
5
posites (Fig. 4, 6–8) has revealed that forming opera-
tion with alumina caused a decrease in the intensity of
6
7
–1
the band at 1545 cm corresponding to vibrations of
pyridine chemisorbed on Brønsted acid sites. This
phenomenon is attributed to the “dilution”
Ni,H/ZSM-5 materials with Al O binder that gives
8
2
3
rise to Lewis acid sites only. The incorporation of alu-
mina accounts for a decrease in Brønsted acidity.
Moreover, it explains an increase in the intensity of
1
700 1650 1600 1550 1500 1450 1400
–1
Wavenumbers, cm–1
bands at about 1615 cm characteristic of PyL and it
contributes to the formation of new surface electron
pair acceptors, i.e. acting as Lewis acids. The latter
suggestion is supported by appearance of new absorp-
Fig. 4. FTIR spectra of pyridine adsorbed on (1) NaZ, (2)
HZ , (3) HZ , (4) NiZ , (5) NiZ , (6) (NiZ –Al O ) , (7)
s
a
s
a
s
2 3 E
–1
(
NiZ –Al O ) and (8) (NiZ –Al O ) .
tion band at 1452 cm .
s
2
3 A
a
2 3 A
KINETICS AND CATALYSIS
Vol. 60
No. 6
2019

PHYSICOCHEMICAL AND CATALYTIC PROPERTIES
Table 4. Acidity of the samples by Py–IR and by NH –TPD measurements
857
3
Py–IR
NH –TPD
3
Sample
acid sites, mmol/g
PyH+
PyH + PyL
+
PyL
total
weak*
medium*
strong*
NaZ
HZs
0.03
0.58
0.68
0.48
0.45
–
–
0.03
0.68
0.78
0.55
0.53
0.25
0.52
0.54
0.40
0.45
0.39
0.10
0.75
0.86
0.70
0.63
0.38
0.54
0.67
0.54
0.58
0.51
0.03
0.09
0.16
0.09
0.16
0.16
0.12
0.09
0.13
0.18
0.16
0.06
0.36
0.42
0.35
0.27
0.16
0.32
0.36
0.27
0.29
0.23
0.01
0.3
0.10
0.10
0.07
0.08
0.25
0.24
0.25
0.16
0.20
0.17
HZa
NiZs
NiZa
Al O
0.28
0.26
0.20
0.04
0.10
0.22
0.15
0.11
0.12
2
3
(
(
(
(
(
NiZ –Al O )
0.28
0.29
0.24
0.25
0.23
s
2
3 E
NiZ –Al O )
3 A
s
2
NiZ –Al O )
3 theor
**
**
s
2
NiZ –Al O )
3 A
a
2
NiZ –Al O )
3 theor
a
2
*
Acid sites were classified as weak, medium and strong, i.e. desorbing ammonia at 180−300, at 300–450 and at 450–550°C, respectively.
*
* Theoretical data calculated based on the proportion of components in binary systems.
+
+
The ion exchange of Na by H increases the acid expected from the proportion of the individual com-
site concentration by ca. 0.7 mmol/g. It appears that a ponents. It can therefore be concluded that the prepa-
higher acidity of exchanged forms of zeolite is ration of zeolite–Al O systems, especially that involv-
2 3
accounted for by increased Brønsted acidity. As can be ing thorough component mixing, favours migration of
seen from the distribution of acid strengths (Table 4), aluminum from alumina to zeolite.
HZ is characterised by a higher acidity of weak (W)
a
The catalytic performance in n-C transformation
and medium (M) sites, as compared with the HZ zeo-
6
s
+
2+
as a function of the reaction temperature (T ) is sum-
r
lite. The exchange of H for Ni reduces primarily
Brønsted acidity (Table 4). The reduction is particu-
larly distinct in the case of the zeolite obtained with
HCl. From the distribution of acid strengths, it is obvi-
marised in Table 5. Since, the HCl treatment of parent
zeolite is accompanied by slight zeolite lattice contrac-
tions the catalytic activity in n-C conversion was con-
6
ducted only with the salt modified catalysts. The reac-
tion products can be divided into four groups. The
products of the first (C –C hydrocarbons) and the
ous that with NiZ the acidity reduction touches strong
s
acid sites (450–550°C), and with NiZ the acidity
a
1
2
reduction occurs at the expense of both strong (S) and
medium sites (300–550°C). In the Ni,H/ZSM-5–
Al O systems, the concentration of Brønsted sites
second groups (C –C hydrocarbons) resulted from
3
5
the cracking reactions. The third group includes i-C6
2
3
decreases by 40 to 45%, since Al O alone, which does isomerization products and the fourth encompasses
2
3
hydrocarbons with boiling temperatures higher than
those of n-C (HBH—high boiling hydrocarbons).
not contain Brønsted sites, shows a relatively high
concentration of Lewis sites. The comparison of
6
(
NiZ –Al O ) and (NiZ –Al O ) indicates that the The latters are produced by the dehydrocyclization
s
2
3 A
s
2
3 E
(
(
DeCYC, mainly alkylcyclopentanes), aromatisation
BTX—benzene, toluene, mainly xylenes), alkylation
use of method A, in which zeolite and alumina pro-
duce a more homogeneous mixture, yields binary sys-
tems with higher acidity (including Brønsted acidity) and polymerisation (all as alkylaromatics). The crack-
than the use of method E, which involves a combina- ing fractions were also described by means of the fol-
tion of two pastes. The (NiZ –Al O ) system is char- lowing parameters: the h/c ratio, the ζ fragmentation
s
2
3 A
factor and i/n ratio for C –C cut. Therefore, h/c ratio
acterized by a higher proportion of both medium (M)
3
5
and strong (S) acid sites, the sites that lose adsorbed represents the mole number of n-C
converted to C –C
1 2
6
ammonia at temperatures higher than 300°C (Table 4).
hydrocarbons to the mole number of n-C converted
6
to C –C hydrocarbons; ζ fragmentation factor
The results of Table 4 indicate that concentrations
3
5
of acid sites in zeolite–Al O systems are higher than expresses the mole number of hydrocarbon fragments
2
3
per mole of n-C cracked (ζ = ΣC /ΣC /6) and i/n
the values derived by calculation based on the propor-
6
i
i
tion of the support components. All the catalytic sys- ratio stands for the mole number of i-alkanes to
tems examined display acidity greater than the level n-alkanes within the C
–C fraction.
5
3
KINETICS AND CATALYSIS Vol. 60 No. 6 2019

8
58
MASALSKA et al.
Table 5. Catalytic performance of the catalysts in n-hexane conversion at selected Tr
Cracking, %
i-C distribution, %
HBH distribution, %
6
Tr, Conv.,
i-C6,
%
HBH,
%
Catalyst
HZs
°C
%
h/ca
ζb
i/nc
+
C ‒C C ‒C
DMC 2-MC 3-MC
DeCYC BTX
1
2
3
5
4
5
5
C8
225 12.5
75 31.4
25 80.8
75 96.6
225 13.4
75 33.0
25 72.5
75 90.3
‒
66.4 <0.1
69.0
72.0
1.5 1.1 15.2
1.6 1.0 8.3
1.6 1.0 3.5
1.8 1.0 1.6
1.4 1.1 14.2
5.3 63.2
31.6 18.4
‒
‒
‒
2
3
3
0.1
0.1
0.3
‒
7.7
7.7
‒
61.5
57.7
‒
30.8 22.6 14.1
59.2 26.8
77.3 16.2
72.3 26.0
62.5 16.7
65.8 19.7
71.4 22.2
74.2 23.8
34.6 24.5
24.3
6.6
1.7
73.8
‒
NiZs
67.9
‒
8.7 60.9
8.0 64.0
30.4 17.9 20.8
28.0 23.0 14.5
2
3
3
0.6
1.8
8.1
‒
68.4 0.01 1.6 0.9 7.9
66.3 0.03 1.7 1.0 3.9 10.0 56.7
61.1 0.14 2.0 0.8 2.0
70.8 1.5 1.1 19.4
33.3 28.0
‒
40.0
6.4
1.9
‒
‒
‒
28.8
9.7
(
NiZ –Al O ) 225
7.2
‒
6.7 53.3
‒
‒
s
2 3 E
2
75 21.9
0.5
1.6
4.9
‒
0.5
1.5
4.7
74.9 0.01 1.6 0.9 9.6 10.0 55.0
75.1 0.02 1.7 0.8 4.1 12.0 56.0
35.0 15.1 21.2
32.0 19.2 17.1
66.7 12.1
78.4 4.5
81.6 9.0
325 57.9
375 86.2
69.8 0.07 1.9 0.8 2.0
75.6 1.5 1.1 15.9 14.3 52.4
81.6 0.02 1.6 1.0 7.8 13.0 52.2
‒
‒
‒
33.3
23.3
8.5
9.5
‒
(
NiZ –Al O ) 225
8.2
‒
‒
‒
s
2 3 A
275 21.7
34.8 10.1 31.8
30.8 17.6 20.2
36.4 31.8
57.4 22.3
74.3 14.8
325 53.4
77.0 0.03 1.7 0.8 3.9 11.5
70.8 0.07 1.8 0.8 2.2
57.7
‒
375 82.2
‒
‒
22.3 10.9
DMC —dimethylbutanes, 2-MC —2-methylpentane, 3-MC —3-methylpentane.
4
5
5
a
b
c
h/c—ratio expressing the mole number of n-C converted to C –C to the mole number of n-C converted to C –C hydrocarbons.
6
1
2
6
3
5
ζ—fragmentation factor expressing the mole number of hydrocarbon fragments per mole of n-C cracked (ζ = ΣC /ΣC /6).
i/n—ratio expressing the mole number of iso-alkanes to n-alkanes within the C –C fraction.
6
i
i
4
5
As can be inferred form Table 5 the n-C conver- (18‒29%). The drop of selectivity to cracking prod-
6
sion on NiZ sample is as high as that observed with a ucts can be attributed to the decline in the number of
s
Brønsted acid sites in NiZ catalyst whereas the
hydrogen zeolite (i.e. HZ ) at low reaction tempera-
tures (225‒275°C) and only slightly (i.e. by about 7%)
lower at higher reaction temperatures (325‒375°C).
s
s
increase in HBH selectivity is associated with the exis-
tence of Ni species, which act as dehydrogenating
+
However, the comparison of the product distribution sites. When nickel exchanges with H Ni ions can
shows some differences between catalytic perfor- occupy both ion exchange sites to form hardly reduc-
mances of these two catalysts especially pronounced ible Ni species and extra framework positions to yield
over the T range of 325‒375°C. In the presence of the readily reducible Ni species. Higher selectivity of
r
HBH hydrocarbons can be attributed to the presence
of Ni species irreducible under the activation proce-
dure that act as Lewis acids and provide active sites for
dehydrogenation. Moreover, Ni species formed by
reduction of Ni extra-framework sites favour the direct
dehydrocyclization to yield HBH compounds. Using
Ni,H/ZSM-5 system as a catalyst Hoang et al.
obtained HBH products in higher yields than in the
presence of H/ZSM-5 [13].
HZ catalyst, the main cracking products (C ‒C
5
s
3
hydrocarbons) are formed with 69‒74% selectivity.
Over the temperature range of 225‒375°C relatively
high HBH selectivity (18‒24%) was observed. The
formation of high boiling products over the catalyst
displaying only acid function agrees with the results
reported by Williams et al. [55] and can be explained
by considering the oligomeric mechanism of n-C
conversion that assumes the alkylation between the
formed alkenes.
6
In general, the conversion of n-hexane on bifunc-
tional (metal–acid) NiZ catalyst can be considered
s
Over the NiZ catalyst, the selectivity to cracking
s
based on the classical monomolecular mechanism.
(
C ‒C ) products amounts to 61‒68%. However, in Nevertheless, due to the relatively low metal content in
3 5
contrast to selectivity found for the metal-free catalyst NiZ (1.4 wt % of Ni) the limiting step could be the n-C
s
6
it decreases with increasing reaction temperature. The dehydrogenation or alkene hydrogenation on metal
catalyst prepared by ion exchanging zeolite with Ni sites. For this reason, concurrent n-C conversion
6
ions shows a slight decrease in selectivity towards involving the bimolecular mechanism (dimerization–
C ‒C cut but at the same time, it produces an cracking) proposed for the bifunctional catalysts with
3
5
enhancement of the selectivity to HBH products unbalanced metal–acid function as well as via the
KINETICS AND CATALYSIS
Vol. 60
No. 6
2019

PHYSICOCHEMICAL AND CATALYTIC PROPERTIES
859
oligomeric pass way described for the acid catalysts mation follows two different reaction mechanisms.
cannot be ruled out
Our results show that the fraction of light hydrocar-
bons (i.e. C ‒C ) is more abundant over the NiZ cat-
1
2
s
The results outlined above demonstrate that
alyst than over the HZ system. However, in the pres-
regardless of method used to combine NiZ zeolite and
s
s
ence of the two-component Ni,H/ZSM-5–Al O cat-
alumina the prepared Ni,H/ZSM-5–Al O compos-
2
3
2
3
alysts the hydrogenolysis selectivity declines as
ites exert some impact on the n-C conversion. With
6
compared to NiZ catalyst that displayed the highest
the NiZ sample the n-C conversion of 13–90% was
s
s
6
hydrogenolysis selectivity. In the case of bifunctional
metal/acid catalysts, the classical monomolecular
mechanism does not account for the C ‒C hydrocar-
reached over the temperatures from 225 to 375°C,
while with the (NiZ –Al O ) and (NiZ –Al O ) cat-
s
2
3 E
s
2
3 A
1
2
alysts conversion over the same temperatures were in
the range of 7‒86% and 8‒82%, respectively. Fur-
thermore, the Ni,H/ZSM-5–Al O catalysts show
bons production because it would imply the formation
of non-stable primary carbocations. Hence, the pres-
ence of Ni metal sites explains a higher activity of the
2
3
different product distribution. Regardless of the cata-
lyst and the conversion level, the main products over
both catalysts were C ‒C hydrocarbons. The selec-
NiZ catalyst in hydrogenolysis proceeded by cracking
s
on metal sites. In our work, this suggestion is corrobo-
rated by two observations. First, the incorporation of
Ni in the zeolite framework gave rise to an increase in
the h/c ratio that is defined as the ratio of the number
of n-C moles transformed to C ‒C to the number of
3
5
tivity not lower than 70% was recorded and in the case
of (NiZ –Al O ) catalyst it was as high as 82%. The
s
2
3 A
decrease in the n-C conversion can be explained by
6
6
1
2
the reduced formation of HBH compounds. This is a
positive phenomenon because the condensation of
HBH compounds results in the formation of carbona-
ceous deposits on the catalyst surface that may lead to
the catalyst deactivation [56]. The decline in catalytic
activity of Ni,H/ZSM-5–Al O catalytic systems
n-C moles converted to C –C . Second, by compar-
6
3
5
ing the NiZ and both two-component catalysts with a
s
half metal concentration after “dilution” with alumina
binder it can be seen that this ratio increased when the
use was made of the catalyst with higher Ni concentra-
tion (Table 5). It should be mentioned, however, that
at low conversions and high reaction temperatures
C –C as well as H could be formed in the presence
2
3
might be due to the fall in the concentration of Brøn-
sted acid sites as well as to the double reduction of the
concentration of Ni species in the composite that has
1
2
2
of a monofunctional acid catalyst or bifunctional cat-
alyst with a poor hydrogenating function. In this case,
the conversion of the alkanes occurs via a non-classi-
cal penta-coordinated carbonium ion following the
monomolecular reaction mechanism.
5
0 wt % of aluminium hydroxide. Furthermore, it
should be also taken into account the possibility of the
formation of hardly reducible and inactive Ni–Al spi-
nels because of strong interaction between Ni species
and alumina [57, 58].
Over all catalysts examined, the selectivity to isom-
erization products is very low and it does not exceed
The distribution of hydrocarbons in the C ‒C cut
1
5
also suggests that transformation of n-C over the
6
20%. Among catalysts investigated, (NiZ –Al O )
investigated metal-acid catalysts is governed in parallel
s 2 3 E
shows the highest selectivity to isomerization prod-
ucts, amounting to 19.4%. However, this result was
observed at the conversion level lower than 10%. The
main isomerization products were represented by
monosubstituted pentanes whereby the 2-methylpen-
tane is formed rather than 3-methylpentane. Yashima
et al. studied n-hexane conversion and observed a
higher selectivity to 2-methylpentane in the presence
of Pt,H/ZSM-5 catalyst. [61]. It was also found that,
the amount of 2-methylpentane produced over the
medium-pore ZSM-5 zeolite (with straight and zig-
zag-channels with diameter of 5.5 × 5.1 and 5.6 × 5.3 Å,
respectively) is higher than in large-pore zeolites. Note
that the mordenite pore system is composed of the
main and side channels with diameter of 6.7 × 7.0 and
by bifunctional monomolecular and dimerization-
cracking mechanisms. If n-C undergoes cracking in
6
accordance with the classical bifunctional monomo-
lecular pathway, propane would be the only product,
since β-scission of the carbenium ions consisting of 6
carbon atoms involves only the type C of β-scission via
the secondary 2-methylpentyl carbenium ions [59].
Hence, it can be suggested that the C and C hydro-
4
5
carbons are formed via the cracking of C intermedi-
1
2
ates when the reaction goes through the dimerization-
cracking pathway. This finding is also supported by the
ζ values lower than 2. Cracking products obtained over
all catalysts are characterised by a low i/n ratio (from
0
.8 to 1.1). It appears that in ZSM-5 zeolite ten ring
channels are too narrow to permit the formation of
2
.6 × 5.7 Å, whereas the pores of beta zeolite are
α,γ,γ-tribranched alkylcarbenium ions from C inter-
1
2
formed by combination of straight and sinusoidal
channels with diameter of 6.6 × 6.7 and 5.6 × 5.6 Å,
respectively [62]. Hence, the transition state shape
selectivity of ZSM-5 accounts for the branching per-
formance and for the preferred formation of 2-meth-
mediates. Hence, the type A of β-scission cannot
occur and the products are generated via type B and C
of β-scission i.e. through the two or one branched
alkylcarbenium ions [60].
The cracking products can be divided in two sepa- ylbranched hydrocarbons. The ZSM-5 channels are
rate groups, i.e. C –C and C –C because their for- not wide enough to permit the production of
1
2
3
5
KINETICS AND CATALYSIS Vol. 60 No. 6 2019

8
60
MASALSKA et al.
dibranched isomers and the branched carbocations
undergo scission to a larger extent because they are
stronger held inside of the zeolite channels.
5. Inui, T., Suzuki, T., Inoue, M., Murakami, Y., and
Takegami, Y., Stud. Surf. Sci. Catal., 1984, vol. 18,
p. 201.
6
. Tarach, K.A., Śrębowata, A., Kowalewski, E.,
Gołąbek, K., Kostuch, A., Kruczała, K., Girman, V.,
and Góra-Marek, K., Appl. Catal., A, 2018, vol. 568,
p. 64.
CONCLUSIONS
(
4
1) The ion exchange in Na/ZSM-5 with HCl or
7
. Podolska-Serafin, K. and Pietrzyk, P., J. Mol. Struct.,
NH Cl followed by exchange with Ni(NO ) yielded
3 2
2
019, vol. 1180, p. 754.
the Ni/ZSM-5 catalysts with a lower microporosity.
After the preparation of the Ni,H/ZSM-5–Al O
8
. De Lucas, A., Valverde, J.L., Dorado, F., Romero, A.,
and Asencio, I., J. Mol. Catal. A: Chem., 2005, vol. 225,
p. 47.
2
3
(
1 : 1) binary systems zeolite channels were not
clogged by alumina species.
9. Gervasini, A., Appl. Catal., A, 1999, vol. 180, p. 71.
(2) Combination of ZSM-5 zeolite with aluminium
1
0. Hagen, A., Schneider, E., Benter, M., Krogh, A.,
hydroxide by mixing powders favours aluminium
migration from aluminum hydroxide/oxide to the
zeolite structure. Support for this suggestion can be
found in acid site concentrations that exceed theoreti-
Kleinert, A., and Roessner, F., J. Catal., 2004, vol. 226,
p. 171.
1
1. Hagen, A., Schneider, E., Kleinert, A., and Roessner, F.,
J. Catal., 2004, vol. 222, p. 227.
27
cally predicted values as well in Al MAS NMR
results that indicate an increased fraction of the frame-
work aluminum in samples obtained by combination
of appropriate pastes.
1
2. Ganjkhanlou, Y., Groppo, E., Bordiga, S., Volkova, M.A.,
and Berlier, G., Microporous Mesoporous Mater., 2016,
vol. 229, p. 76.
13. Hoang, D.L., Berndt, H., Miessner, H., Schreier, E.,
Völter, J., and Lieske, H., Appl. Catal., A, 1994,
vol. 114, p. 295.
(3) The decline of Brønsted acidity in Ni,H/ZSM-5
as compared to that in H/ZSM-5 results in a lower
selectivity for cracking products. At the same time, the
presence of Ni species in Ni,H/ZSM-5 accounts for
its higher selectivity towards hydrocarbons with boil-
ing points above the those of n-hexane.
1
4. Kinger, G., Lugstein, A., Swagera, R., Ebel, M., Jen-
tys, A., and Vinek, H., Microporous Mesoporous Mater.,
000, vol. 39, p. 307.
2
1
5. Round, C.I., Williams, C.D., Latham, K., and
Duke, C.V.A., J. Therm. Anal. Calorim., 2001, vol. 63,
(
4) To reach n-hexane conversion level over the
p. 329.
Ni,H/ZSM-5–Al O catalytic system that would be
2
3
1
6. Romero, M.D., De Lucas, A., Calles, J.A., and Rodri-
comparable to that observed in the presence of the
Ni,H/ZSM-5 approximately 25°C higher reaction
temperatures are needed. The lower activity of two-
component catalysts brings about the loss of selectivity
to dehydrocyclization products. The changes in the
activity and selectivity observed on passing from two-
component systems to the Ni,H/ZSM-5 catalyst may
be a consequence of reduced Brønsted acidity (by
about 45%) as well as double reduction of the number
of Ni species.
guez, A., Appl. Catal., 1996, vol. 146, p. 425.
1
7. Mitchell, S., Michels, N.L., and Perez-Ramirez, J.,
Chem. Soc. Rev., 2013, vol. 42, p. 6094.
1
8. Whiting, G.T., Chung, S.H., Stosic, D., Chowdhury, A.D.,
Wal, Van Der L.I., Fu, D., Zecevic, J., Travert, A.,
Houben, K., Baldus, M., and Weckhuysen, B.M., ACS
Catal., 2019, vol. 9, p. 4792.
1
9. Bingre, R., Louis, B., and Nguyen, P., Catalysts, 2018,
vol. 8, p. 163.
2
0. Chen, X.D., Li, X.G., Li, H., Han, J.J., and Xiao, W.D.,
Chem. Eng. Sci., 2018, vol. 192, p. 1081.
2
1. Aboul-Gheit, A.K., Aboul-Fotouh, S.M., Abdel-Ha-
mid, S.M., and Aboul-Gheit, N.A.K., J. Mol. Catal. A:
Chem., 2006, vol. 245, p. 167.
ACKNOWLEDGMENTS
The work was financed by a statutory activity subsidy
from the Ministry of Science and Higher Education,
Republic of Poland for the Faculty of Chemistry of
Wrocław University of Science and Technology
22. Aboul-Gheit, A.K. and Aboul-Gheit, N.A.K., Appl.
Catal., A, 2006, vol. 303, p. 141.
23. De Lucas, A., Valverde, J.L., Sanchez, P., Dorado, F.,
(
0401/0144/18).
and Ramos, M.J., Appl. Catal., A, 2005, vol. 282, p. 15.
2
4. De Lucas, A., Valverde, J.L., Sanchez, P., Dorado, F.,
and Ramos, M.J., Ind. Eng. Chem. Res., 2004, vol. 43,
p. 8217.
REFERENCES
1
. Maia, A.J., Louis, B., Lam, Y.L., and Pereira, M.M., J. 25. Dorado, F., Romero, R., and Cañizares, P., Appl.
Catal., 2010, vol. 269, p. 103.
Catal., A, 2002, vol. 236, p. 235.
2. BR Patent 200305957-A, 2003.
26. Kantarelis, E., Yang, W., and Blasiak, W., Fuel, 2014,
vol. 122, p. 119.
3. Qi, S.C., Wei, X.Y., Zong, Z.M., Hayashi, J., Yuan, X.H.,
and Sun, L.B., ChemCatChem., 2013, vol. 5, p. 3543.
27. Zhang, Y., Zhou, Y., Qiu, A., Wang, Y., Xu, Y., and
Wu, P., Ind. Eng. Chem. Res., 2006, vol. 45, p. 2213.
4. Yung, M.M., Starace, A.K., Mukarakate, C., Crow, A.M.,
Leshnov, M.A., and Magrini, K.A., Energy Fuels, 2016, 28. Du X., Kong X., and Chen L., Catal. Commun., 2014,
vol. 30, p. 5259.
vol. 45, p. 109.
KINETICS AND CATALYSIS
Vol. 60
No. 6
2019

PHYSICOCHEMICAL AND CATALYTIC PROPERTIES
861
2
9. Choudhary, V.R., Devadas, P., Kinage, A.K., and 47. Meng, L., Zhu, X., Wannapakdee, W., Pestman, R.,
Guisnet, M., Appl. Catal., A, 1997, vol. 162, p. 223.
Goesten, M.G., Gao, L., van Hoof A.J.F, and
Hensen, E.J.M., J. Catal., 2018, vol. 361, p. 135.
30. Dorado, F., Romero, R., and Caňizares, P., Ind. Eng.
Chem. Res., 2001, vol. 40, p. 3428.
4
4
5
8. Hu, J.Z., Wan, C., Vjunov, A., Wang, M. Zhao, Z.,
Hu, M.Y., Camaioni, D.M., and Lercher, J.A., J. Phys.
Chem. C, 2017, vol. 121, p. 12849.
9. Fougerit, J.M., Gnep, N.S., Guisnet, M., Amigues, P.,
Duplan, J.H., and Hugues, F.E., Stud. Surf. Sci. Catal.,
1994, vol. 84, p. 1723.
31. Ringelhan, C., Burgfels, G., Neumayr, J.G., Seuffert, W.,
Klose, J., and Kurth, V., Catal. Today, 2004, vol. 97,
p. 277.
32. Wu, X., Alkhawaldeh, A., and Anthony, R.G., Stud.
Surf. Sci. Catal., 2002, vol. 143, p. 217.
3
3. Kung, H.H., Williams, B.A., Babitz, S.M., Miller, J.T.,
Haag, W.O., and Snurr, R.Q., Top. Catal., 2000, vol. 10,
p. 59.
0. Shen, S.C. and Kawi, S., Langmuir, 2002, vol. 18,
p. 4720.
5
1. Tamasi, A., Niesz, K., Palinko, I., Guczi, L., and
3
3
3
4. Kung, H.H., Res. Chem. Intermed., 2000, vol. 26,
Kiricsi, I., Stud. Surf. Sci. Catal., 2002, vol. 142,
p. 121.
p. 1801.
5. Luo, J. and Gorte, R.J., Catal. Lett., 2013, vol. 143,
5
2. Park, S., Biligetu, T., Wang, Y., Nishitoba, T., Kondo, J.N.,
p. 313.
and Yokoi, T., Catal. Today, 2018, vol. 303, p. 64.
6. Jentoft, F.C. and Gates, B.C., Top. Catal., 1997, vol. 4,
5
3. Deng, C., Zhang, J., Dong, L., Huang, M., Li, B., Jin, G.,
Gao, J., Zhang, F., Fan, M., Zhang, L., and Gong, Y.,
Sci. Rep., 2016, vol. 6, p. 23382.
p. 1.
37. Kotrel, S., Knözinger, H., and Gates, B.C., Micropo-
rous Mesoporous Mater., 2000, vols. 35–36, p. 11.
5
4. Meng, F., Wang, Y., and Wang, X., Kinet. Catal., 2018,
38. Huang, B., Bai, P., Neurock, M., and Davis, R.J., Appl.
vol. 59, p. 304.
Catal., A, 2017, vol. 546, p. 149.
3
9. Loc, L.C., Tri, N., Thoa, D.T.K., Gaidai, N.A., Aga- 55. Williams, B.A., Ji, W., Miller, J.T., Snurr, R.Q., and
fonov, Y.A., Anh, H.C., Cuong, H.T., and Lapidus, A.L.,
Kung, H.H., Appl. Catal., A, 2000, vol. 203, p. 179.
Kinet. Catal., 2017, vol. 58, p. 311.
5
6. Wei, J., Yao, R., Ge, Q., Wen, Z., Ji, X., Fang, C.,
Zhang, J., Xu, H., and Sun, J., ACS Catal., 2018, vol. 8,
p. 9958.
40. Lugstein, A., Jentys, A., and Vinek, H., J. Chem. Soc.,
Faraday Trans., 1997, vol. 93, p. 1837.
4
1. Emeis, C.A., J. Catal., 1993, vol. 141, p. 347.
5
5
5
7. Navalikhina, M.D. and Krylov, O.V., Kinet. Catal.,
4
4
4
4
4
2. Gavrilov, V.Y., Krivoruchko, O.P., Larina, T.V., Moli-
na, I.Y., and Shutilov, R.A., Kinet. Catal., 2010, vol. 51,
p. 88.
3. Treacy, M.M.J. and Higgins, J.B., Collection of Simu-
lated XRD Powder Patterns for Zeolites, Amsterdam: El-
sevier, 2007, IZA ed., p. 278.
2001, vol. 42, p. 264.
8. Tomina, N.N., Nikul’shin, P.A., and Pimerzin, A.A.,
Kinet. Catal., 2008, vol. 49, p. 653.
9. Cnudde, P., De Wispelaere, K., Vanduyfhuys, L., De-
muynck, R., Van der Mynsbrugge, J., Waroquier, M.,
and Van Speybroeck, V., ACS Catal., 2018, vol. 8,
p. 9579.
4. Li, S., Zheng A., Su, Y., Fang, H., Shen, W., Yu, Z.,
Chen, L., and Deng, F., Phys. Chem. Chem. Phys.,
60. Chen, C.J., Rangarajan, S., Hill, I.M., and Bhan, A.,
2010, vol. 12, p. 3895.
ACS Catal., 2014, vol. 4, p. 2319.
5. Gackowski, M., Kuterasiński, Ł., Podobiński, J., Suli-
61. Yashima, T., Wang, Z.B., Kamo, A., Yoneda, T., and
kowski, B., and Datka, J., Spectrochim. Acta, Part A,
Komatsu, T., Catal. Today, 1996, vol. 29, p. 279.
2018, vol. 193, p. 440.
6. Agliullin, M.R., Grigor’eva, N.G., Danilova, I.G., 62. Sazama, P., Pastvova, J., Kaucky D., Moravkova, J.,
Magaev, O.V., and Vodyankina, O.V., Kinet. Catal.,
015, vol. 56, p. 501.
Rathousky, J., Jakubec, I., and Sadovska, G., J. Catal.,
2018, vol. 364, p. 262.
2
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