Synthesis of ZSM-12 Zeolites with New Templates Based on Salts of Ethanolamines

Article abstract of DOI:10.1134/S1070427218120066

New class of templates, ethanolamine salts, was used to synthesize zeolites with the ZSM-12 structure. The materials obtained were characterized by methods of powder X-ray diffraction, scanning electron microscopy, IR spectroscopy, low-temperature adsorption–desorption of nitrogen, and elemental analysis. It was shown that, with these templates, it is possible to obtain crystallites with well formed acicular shape, hexagonal morphology, large surface area, and narrow pore size distribution.

Full text of DOI:10.1134/S1070427218120066

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2018, Vol. 91, No. 12, pp. 1957−1962. © Pleiades Publishing, Ltd., 2018.
Original Russian Text © D.E. Tsaplin, D.A. Makeeva, L.A. Kulikov A.L. Maksimov, E.A. Karakhanova, 2018, published in Zhurnal Prikladnoi Khimii, 2018,
Vol. 91, No. 12, pp. 1729−1734.
INORGANIC SYNTHESIS
AND INDUSTRIAL INORGANIC CHEMISTRY
Synthesis of ZSM-12 Zeolites with New Templates
Based on Salts of Ethanolamines
D. E. Tsaplina, D. A. Makeevaa, L. A. Kulikova,b,*, A. L. Maksimova,b, and E. A. Karakhanova
a Lomonosov Moscow State University, Moscow, 119991 Russua
b Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, 119991 Russia
*e-mail: mailforleonid@mail.ru
Received October 9, 2018
Abstract—New class of templates, ethanolamine salts, was used to synthesize zeolites with the ZSM-12 structure.
The materials obtained were characterized by methods of powder X-ray diffraction, scanning electron microscopy,
IR spectroscopy, low-temperature adsorption–desorption of nitrogen, and elemental analysis. It was shown that,
with these templates, it is possible to obtain crystallites with well formed acicular shape, hexagonal morphology,
large surface area, and narrow pore size distribution.
Keywords: zeolites, ZSM-12, ethanolamines, hydrothermal synthesis
DOI: 10.1134/S1070427218120066
Xylenes are among the most industrially valuable
substances, which serve as raw materials for synthesis of
dyes and plasticizers and are used as solvents. Of particular
importance among these substances is para-xylene used
to synthesize terephthalic acid for subsequently obtaining
synthetic polymeric fibers. Therefore, the demand for
para-xylene substantially exceeds that for other xylenes.
is characterized by a 1D system of channels formed by
12-member rings and 5.7 × 6.1 Å pores (Fig. 1).
A large number of studies concerned with synthesis
and catalytic properties of ZSM-12 zeolite have been
published [2–7]. The properties of the materials being
synthesized, such as the particle morphology and activity
in chosen catalytic processes, are largely determined by
the choice of a template. Therefore, a search for new
templates and analysis of how their structure affects the
properties of the resulting zeolites seem to be topical
tasks.
One of ways to solve the problem of providing the
industry with a sufficient amount of para-xylene is to
obtain it via polymerization of meta- and ortho-xylenes
and ethylbenzene and also via alkylation of benzene and
toluene. The processes require that acid catalysts should
be used. The most promising strategy for performing these
catalytic transformations is based on using materials with
a special elongated configuration of pores interconnected
by narrow channels.Astructure of this kind favors a more
easy diffusion of para-xylene from pores into the ambient
medium and, consequently, its higher yield in the course
of synthesis. Astructure of this kind is possessed by MFI
(ZSM-5) or MOR zeolites and also by the increasingly
popular zeolite of the MTW (ZSM-12) type, which was
first obtained in 1974 by Mobil Oil [1]. This material
The present study is concerned with new types of
templates, salts of ethanolamines (dimethyl ethanolamine
and methyl diethanolamine), used to synthesize ZSM-12
zeolites. The materials obtained are examined by the
methods of powder X-ray diffraction, scanning electron
microscopy (SEM), IR spectroscopy, low-temperature
adsorption–desorption of nitrogen, and elemental analysis.
Also, the properties of the ZSM-12 zeolites synthesized
with new templates with the materials obtained under
similar conditions with the conventional templates, salts
of tetraethylammonium and triethylmethylammonium.
1957

1958
TSAPLIN et al.
in a rotary evaporator to remove the excess amount of
ethyl bromide. A colorless amorphous product with a
mass of 19.8 g was obtained. 1Н NMR spectrum, δ (ppm)
(DMSO-d6): 1.22 (3H, t), 3.04 (6H, s), 3.37–3.41 (2H,
q), 3.40–3.44 (2H, m), 3.79 (2H, br. s), 5.28 (1H, br.s).
Synthesis of diethanol-N-methyl-N-ethylammo-
nium bromide [MED(EtOH)A]Br. A 50-mL flask
equipped with the core of a magnetic rabble was charged
with methyldiethanolamine (11.5 mL, 0.1 mol) and ethyl
bromide (7.8 mL, 0.105 mol). The reaction was performed
under agitation in the course of 12 h. The resulting mix-
ture was evaporated under reduced pressure in a rotary
evaporator to remove the excess amount of ethyl bromide.
Acolorless amorphous product with a mass of 22.6 g was
obtained. 1Н NMR spectrum, δ (ppm) (DMSO-d6): 1.22
(3H, t), 3.05 (3H, s), 3.37–3.41 (2H, q), 3.43–3.49 (4H,
q), 3.77–3.81 (4H, m), 5.25 (2H, t).
Fig. 1. Typical structure of the ZSM-12 zeolite.
EXPERIMENTAL
The zeolites were synthesized from the following
reagents: colloid solution of silicon oxide Ludox
HS-40 (40 wt %, Sigma-Aldrich), aluminum sulfate
octadecahydrate [Al2(SO4)3·18H2O, Sigma-Aldrich,
99%], tetraethylammonium bromide ([TEA]Br, Sigma-
Aldrich, 98%), methyltetraethylammonium chloride
([MTEA]Cl, Sigma-Aldrich, 97%, dimethylethanolamine
[(CH3)2NC2H4OH, Sigma-Aldrich, 98%],
methyldiethanolamine [CH3N(C2H4OH)2, Sigma-
Aldrich, 98%)], bromoethane (C2H5Br, Sigma-Aldrich,
99%), sodium hydroxide (NaOH, Komponent-Reaktiv,
98%, and ammonium chloride (NH4Cl, Khimmed, 98%).
ZSM-12 zeolites were synthesized by the previously
described methods under hydrothermal conditions [5, 8].
The zeolites being synthesized are listed in Table 1.
The typical procedure includes preparing a gel by
mixing solutions containing aluminum sulfate, sodium
hydroxide, and a template (solution 1, H2O : Al2O3 :
template : Na2O = 1157.4 : 1 : 35 : 20.8) and a colloid
solution of silicon oxide (solution 2, H2O : SiO2 = 3.3 : 1).
Further, the gel was transferred into an autoclave equipped
with a Teflon insert and the synthesis was performed
under hydrothermal conditions in a drying box with air
convection at a temperature of 155°C in the course of
120 h. The resulting product was washed with water to
remove remains of the reaction mixture, dried, calcined,
and an ion exchange was performed to obtain the NH4
form of the zeolite. A repeated drying and calcination
of the product yielded a wide powder of the H form of
ZSM-12 zeolites.
Synthesis of monoethanol-N,N-dimethyl-N-
ethylammonium bromide [DMER(EtOH)A]Br.A50-mL
flask equipped with the core of a magnetic rabble was
charged with dimethylethanolamine (10.0 mL, 0.1 mol)
and ethyl bromide (7.8 mL, 0.105 mol). The reaction
was performed under agitation in the course of 12 h. The
resulting mixture was evaporated under reduced pressure
SEM micrographs of samples were obtained on a
Hitachi TM3030 bench-top scanning electron microscope.
The information about the local elemental composition
and element distribution over the sample surface was
obtained with an energy-dispersive spectrometer (EDX)
with Quantax 70 hardware-software system.
Table 1. Zeolites synthesized and examined in the study
SiO2/Al2O3
Sample
Template
[TEA]Br
ZSM-12-A-280
ZSM-12-B-280
ZSM-12-C-280
ZSM-12-D-280
ZSM-12-B-140
ZSM-12-C-140
[МТЕА]Cl
The elemental analysis was made on a Thermo ARL
PERFORM’X instrument with a 2500-V X-ray tube. Prior
to an analysis, 200-mg samples were compacted into a
pellet with boric acid.
280
[DME(EtOH)A]Br
[MED(EtOH)A]Br
[МТЕА]Cl
140
The X-ray analysis was made on a Rigaku Rotaflex D/
max-RC instrument with CuKα radiation (λ = 0.154 nm).
[DME(EtOH)A]Br
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 12 2018

SYNTHESIS OF ZSM-12 ZEOLITES
1959
The diffraction pattern of a sample was recorded at angles
2θ = 3–50° with a step of 0.04° at a scanning rate of
4 deg min–1. The degree of crystallinity was calculated
from the ratio between the areas (integral intensities)
of peaks associated with the crystalline and amorphous
phases.
the temperature was gradually raised to 700°C at a rate
of 10 deg min–1.
The zeolites were analyzed by Fourier transformed
IR spectroscopy on a Thermo Scientific Nicolet IR2000
instrument with multiple frustrated total internal reflection
with a Multireflection HATR attachment containing a
45° ZnSe crystal for various wavelength ranges with a
resolution of 4 nm.
The nitrogen adsorption–desorption isotherms were
recorded at a temperature of 77 K on a Micromeritics
Gemini VII 2390 (V1.02t) instrument. Prior to
measurements, samples were degassed at a temperature
of 300°C for 6 h. The surface area was calculated by the
Brunauer–Emmett–Teller (BET) method from adsorption
data at relative pressures p/p0 = 0.05–0.2. The total pore
volume was determined from the amount of nitrogen
adsorbed at a relative pressure p/p0 = 0.95.
RESULTS AND DISCUSSION
The diffraction patterns of the zeolite samples obtained
at different Si/Al ratios with various templates are
presented in Fig. 2. Signals characteristic of the ZSM-12
zeolite are observed in all cases, which confirms that the
required product is formed. All the peaks indicate that a
material is formed with a crystal lattice of monoclinic
C2/c crystallographic system, which corresponds to
the structure first obtained by researchers from Mobil
[1, 9, 10]. In addition, the absence of a rise in peaks at 2θ =
17–30° is indicative of the large degree of crystallinity of
the resulting zeolites. It should also be noted that nearly
all the zeolite samples contain a minor amount of the
ZSM-5 impurity phase.
The acidity of the samples was determined with
a Micromeritics AutoChem HP2950 instrument. For
this purpose, a sample under study with 250–500-μm
granulometric composition and mass of about 300 mg
was placed in a quartz reactor and blown-through with
nitrogen at 300°C for 1 h. The saturation with ammonia
was performed in a flow of an ammonia/nitrogen
mixture of gases at a temperature of 100°C for 30 min.
The physically adsorbed ammonia was removed at
100°C in a flow of nitrogen in the course of 30 min by
blowing-through with helium at a rate of 50 mL min–1.
To obtain a temperature-programmed desorption curve,
IR spectroscopic data also confirm that the zeolites
synthesized in the study belong to the MTW class with
ZSM-12 structure (Fig. 3). The spectra of all the zeolites
Cristobalite
ZSM-12-C-140
ZSM-12-B-140
ZSM-12-D-280
ZSM-12-C-280
ZSM-12-B-280
ZSM-12-А-280
5
10
15
20
25
30
2θ, deg
35
40
45
50
Fig. 2. Diffraction patterns of samples of the zeolites synthesized in the study.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 12 2018

1960
TSAPLIN et al.
(b)
(a)
ZSM-12-A-280
ZSM-12-B-280
ZSM-12-D-280
ZSM-12-C-280
1200
1000
800
600
1200
1000
800
600
Wave number, cm–1
Wave number, cm–1
Fig. 3. IR spectra of ZSM-12 zeolites: (a) ZSM-12-A-280 and ZSM-12-B-280 and (b) ZSM-12-C-280 and ZSM-12-D-280.
contain at 450–1400 cm–1 a number of absorption bands
characteristic of ZSM-12 materials, peaked at 480
(δb O–Si–O), 543, 580 (νs Si–O–Si + δ O–Si–O), 640
(νs Si–O–Al), 785 (νs Si–O–Si), 1060–1068 [νas Si–O(Si/
Al), in the bulk of the material], and 1211–1220 cm–1 [νas
Si–O(Si/Al), on the surface of the material]. The presence
of absorption bands at 543, 580, and 640 cm–1 directly
evidence that the material has structures formed by a
prism with bases formed by 12-member rings. These data
agree with those obtained previously [11, 12].
desorption of nitrogen. A typical run of the nitrogen
adsorption–desorption curves for the materials obtained is
shown in Fig. 4.At low pressures (p/p0 = 0–0.05), there is
a strong absorption of nitrogen, which indicates that there
are micropores in the structure of the zeolites. In some
cases, the curves show a small hysteresis between the
adsorption and desorption curves, which is characteristic
of mesoporous materials. The presence of mesopores
with average size of about 3.6–3.8 nm may be due to the
formation of voids in aggregation of several crystallites
in the course of the hydrothermal synthesis [12–15]. The
zeolites have large values of the specific surface area and
pore volume, presented below.
The porosity characteristics of the materials were
examined by the method of low-temperature adsorption–
Figure 5 shows SEM micrographs of the zeolites and
the average crystal size of each of these. It is noteworthy
that different crystallite shapes are observed for zeolites
synthesized with various templates, which is due to
the different mechanisms of interaction of template
molecules with silicon dioxide in the course of the
crystallization [16]. A spherical/cubic particle shape and
a rather narrow particle size distribution are characteristic
of ZSM-12-A-280 (Fig. 5a). Materials with a similar
morphology have also been obtained with templates based
on tetraethylammonium {2, 3, 17, 18]. The crystals of
ZSM-12-B-280 and ZSM-12-B-140 zeolites (Figs. 5b and
5c) are rather widely distributed over sizes and shapes:
both rather small particles that resemble in shape rice
grains and well formed coarse crystals are observed. The
particle shape similar to a rice grain of zeolites produces
ZSM-12-B-280
ZSM-12-C-280
0.2
0.6
1.0
Relative pressure p/p0
Fig. 4. Typical run of the nitrogen adsorption–desorption curves
for ZSM-12 zeolites for the example of ZSM-12-B-280 and
ZSM-12-C-280 materials.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 12 2018

SYNTHESIS OF ZSM-12 ZEOLITES
(b)
1961
(a)
(c)
ZSM-12-А-280
ZSM-12-B-140
ZSM-12-B-280
2 μm
2 μm
2 μm
(d)
(e)
(f)
ZSM-12-С-140
ZSM-12-С-280
ZSM-12-В-280
2 μm
2 μm
2 μm
Fig. 5. SEM micrographs of the zeolites (a) ZSM-12-А-280, (b) ZSM-12-B-140, (c) ZSM-12-B-280, (d) ZSM-12-C-140, (e) ZSM-
12-C-280, (f) ZSM-12-D-280.
with this template also agrees with previously published
data [14, 18]. For the ZSM-12-C-140, ZSM-12-D-280,
and ZSM-12-D-280 zeolites, the crystallites have an
elongated shape with a rather narrow size distribution.An
acicular, well formed shape of crystals with a hexagonal
morphology is observed.
CONCLUSIONS
ZSM-12 zeolites were synthesized with ethanolamine
salts used as templates. It was shown that the
structure of templates strongly affects the properties
of the materials obtained: materials based on the
“conventional” templates, salts of tetraethylammonium
and triethylmethylammonium have a cubic and spherical
morphology of their crystallites and are characterized
by, on the whole, smaller particle size and larger surface
area and pore volume.At the same time, zeolites obtained
on the basis of the new templates have a substantially
better formed shape of crystals, which may be due to the
stronger interaction of template molecules with the zeolite
material in the course of crystallization.
The main characteristics of the zeolites are listed
in Table 2. It is noteworthy that, according to the
results of an elemental analysis, the Si/Al ratio in the
materials synthesized is smaller than the calculated
value. This phenomenon, possibly due to the incomplete
transformation of silicon dioxide from the colloid form to
the crystalline phase in the course of the crystallization
process, was also observed in a number of other studies
[19–21].
Table 2. Characteristics of the zeolites
Surface area by BET,
m2 g–1
Pore volume,
Average crystallite size,
Zeolite
Elemental composition
cm3 g–1
μm
ZSM-12-A-280
ZSM-12-B-140
ZSM-12-B-280
ZSM-12-C-140
ZSM-12-C-280
ZSM-12-D-280
187
262
274
196
188
183
0.12
0.11
0.13
0.06
0.09
0.07
0.08Na2O : Al2O3 : 185SiO2
0.1Na2O : Al2O3 : 117SiO2
0.2Na2O : Al2O3 : 226SiO2
0.02Na2O : Al2O3 : 126SiO2
0.11Na2O : Al2O3 : 201SiO2
0.16Na2O : Al2O3 : 217SiO2
0.9
4.4
3.6
8.5
11.2
6.1
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 12 2018

1962
TSAPLIN et al.
no. 1, pp. 11–25.
ACKNOWLEDGMENTS
10. US Patent 4 452 769 (publ. 1983).
The study was financially supported by the Ministry of
Education and Science of the Russian Federation, Federal
target program “Research and development in priority
areas of the scientific-technological complex of Russia
for the years of 2014–2020,” Arrangement 1.4, Subsidy
agreement no. 14.610.21.0009 of 0.3.10.2017. Unique
agreement identifier RFMEFI61017X0009.
11. Zhu, H.-B., Xia, Q.-H., Guo, X.-T., Su, K.-X., Hu, D.,
Ma, X., Zeng, D., and Deng, F., Mater. Lett., 2006, vol. 60,
nos. 17–18, pp. 2161–2166.
12. Wu, W., Wu, W., Kikhtyanin, O.V., Li, L., Toktarev, A.V.,
Ayupov, A.B., Khabibulin, J.F., Echevsky, G.V., and
Huang, J., Appl. Catal. A, 2010, vol. 375, no. 2, pp. 279–
288.
13. Carvalho, K.T.G. and Urquieta-Gonzalez, E.A., Catal.
Today, 2015, vol. 243, no. 1, pp. 92–102.
REFERENCES
14. Chiche, B.H., Dutartre, R., Di Renzo, F., and Fajula, F.,
1. US Patent 3 832 449 (publ. 1974).
Catal. Lett., 1995, vol. 31, no. 4, pp. 359–366.
2. Dimitrov, L., Mihaylov, M., Hadjiivanov, K., Mavro-
dinova, V., Microporous Mesoporous Mater., Elsevier Inc.,
2011, vol. 143, nos. 2–3, pp. 291–301.
15. Xia, Q.-H., Shen, S.-C., Song, J., Kawi, S., and Hidajat, K.,
J. Catal., 2003, vol. 219, no. 1, pp. 74–84.
16. Ritsch, S., Ohnishi, N., Ohsuna, T., Hiraga, K.,
Terasaki, O., Kubota, Y., and Sugi, Y., Chem. Mater., 1998,
vol. 10, no. 12, pp. 3958–3965.
3. Jegatheeswaran, S., Cheng, C.M., and Cheng, C.H.,
Microporous Mesoporous Mater., Elsevier Inc., 2015,
vol. 201, no. C, pp. 24–34.
17. Zhao, Y., Zhang, H., Wang, P., Xue, F., Ye, Z., Zhang, Y.,
and Tang, Y., Chem. Mater., 2017, vol. 29, no. 8, pp. 3387–
3396.
4. Li, J., Lou, L.-L., Xu, C., and Liu, S., Catal. Commun.,
Elsevier B, V, 2014, vol. 50, pp. 97–100.
5. Sanhoob, M.A., Muraza, O., Taniguchi, T., Tago, T.,
Watanabe, G., and Masuda, T., Microporous Mesoporous
Mater., 2014, vol. 194, pp. 31–37.
18. Mehla, S., Krishnamurthy, K.R., Viswanathan, B.,
John, M., Niwate, Y., Kishore Kumar, S.A., Pai, S.M.,
and Newalkarb, B.L., Microporous Mesoporous Mater.,
Elsevier Inc., 2013, vol. 177, pp. 120–126.
6. Masoumifard, N., Kaliaguine, S., and Kleitz, F.,
Microporous Mesoporous Mater., 2016, vol. 227, pp. 258–
271.
19. Souza, M.J.B., Silva, A.O.S., Garrido Pedrosa, A.M., and
Araujo,A.S., React. Kinet. Catal. Lett., 2005, vol. 84, no. 2,
pp. 287–293.
7. Chaves, T.F., Carvalho, K.T.G., Urquieta-González, E.A.,
and Cardozo, D., Catal. Lett., 2016, vol. 146, no. 10,
pp. 2200–2213.
20. Araujo, A.S., Silva, A.O.S., Souza, M.J.B.,
Coutinho, A.C.S.L.S., Aquino, J.M.F.B., Moura, J.A., and
Pedrosa, A.M.G., Adsorption, 2005, vol. 11, no. 2. Spec.
Issue, pp. 159–165.
8. Sanhoob, M.A., Muraza, O., Al-Mutairi, E.M., and
Ullah, N., Adv. Powder Technol. Soc., Powder Technol.
Japan, 2015, vol. 26, no. 1, pp. 188–192.
21. Gopal, S., Yoo, K., and Smirniotis, P.G., Microporous
Mesoporous Mater., 2001, vol. 49, nos. 1–3, pp. 149–156.
9. Kinski, I., Daniels, P., Deroche, C., Marler, B., and
Gies, H., Microporous Mesoporous Mater., 2002, vol. 56,
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 12 2018