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propene and pentene. The monomolecular mechanism domi-
nated the coked ferrierite and all the ferrierite catalysts
exhibited a rapid decrease in conversion and a signicant
increase in selectivity. On the other hand, the nitrogen
adsorption–desorption and TGA results show that Smic and Vmic
of the coked ferrierite catalysts are almost fully blocked by
carbonaceous depositions. The nitrogen adsorption–desorption
and NH3-TPD results indicate that Sext and Vmes of the coked
ferrierite catalysts are still accessible, and the coked N-FER
(2000 min) has the largest values of Sext and Vmes (Sext ¼ 33
m2 gꢂ1 and Vmes ¼ 0.08 cm3 gꢂ1). The Sext (9 m2 gꢂ1) and Vmes
(0.04 cm3 gꢂ1) of the coked S-FER (2000 min) is smaller, and
those (Sext ¼ 2 m2 gꢂ1 and Vmes ¼ 0.00 cm3 gꢂ1) of the coked T-
FER (2000 min) are the smallest. The amount of acid over these
3 M. Trombetta, G. Busca, S. Rossini, V. Piccoli, U. Cornaro,
A. Guercio, R. Catani and R. J. Willey, J. Catal., 1998, 179,
581–596.
4 S. H. Lee, C. H. Shin and S. B. Hong, J. Catal., 2004, 223, 200–
211.
5 L. Domokos, L. Lefferts, K. Seshan and J. A. Lercher, J. Catal.,
2001, 203, 351–361.
6 P. A. Vaughan, Acta Crystallogr., 1966, 21, 983–990.
7 I. S. Kerr, Nature, 1966, 210, 294–295.
8 M. B. D. Santos, H. M. C. Andrade and A. J. S. Mascarenhas,
Microporous Mesoporous Mater., 2016, 223, 105–113.
9 M. Zhang, S. Xu, Y. Wei, J. Li, J. Chen, J. Wang, W. Zhang,
S. Gao, X. Li, C. Wang and Z. Liu, RSC Adv., 2016, 6,
95855–95864.
coked catalysts is in the order: N-FER (2000 min) > S-FER (2000 10 X. Chen, T. Todorova, A. Vimont, V. Ruaux, Z. Qin,
min) > T-FER (2000 min), which has the same sequence as that
obtained with Sext and Vmes. The activity of the catalysts followed
J. P. Gilson and V. Valtchev, Microporous Mesoporous
Mater., 2014, 200, 334–342.
the same order with the amount of acid. Hence, we can 11 P. Frontera, S. Candamano, A. Macario, F. Creab,
conclude that the deactivation of ferrierite was caused by
increased carbon deposition in the cage or channel of ferrierite,
L. A. Scarpino and P. L. Antonucci, Mater. Lett., 2013, 104,
72–75.
fully blocking the pore mouth and the external surface.46,47,56 12 R. Arletti, G. Vezzalini, S. Quartieri, F. D. Renz and
Moreover, we found that both fresh and coked N-FER have
bigger external surface area and mesopore volume, which leads
V. Dmitriev, Microporous Mesoporous Mater., 2014, 191, 17–
27.
to more pore mouth acid sites. This was evidenced by nitrogen 13 T. Xue, H. P. Liu and Y. M. Wang, RSC Adv., 2015, 5, 12131–
adsorption–desorption, Py-IR and NH3-TPD. This explains why 12138.
higher activity and better stability were obtained on N-FER aer 14 P. Wuamprakhon, C. Wattanakit, C. Warakulwit,
a longer stream time.
T. Yutthalekha, W. Wannapakdee, S. Ittisanronnachai and
J. Limtrakul, Microporous Mesoporous Mater., 2016, 219, 1–9.
15 A. B. Pinar, L. Gomez-Hortiguela and J. Perez-Pariente,
Chem. Mater., 2007, 19, 5617–5626.
4. Conclusions
Ferrierite catalysts with different crystal morphologies and sizes 16 Y. Lee, M. B. Park, P. S. Kim, A. Vicente, C. Fernandez,
were designed through hydrothermal synthesis in an alkali I. S. Nam and S. B. Hong, ACS Catal., 2013, 3, 617–621.
solution using different structure-directing agents and crystal- 17 B. Yang, J. G. Jiang, H. Xu, Y. Liu, H. Peng and P. Wu, Appl.
lization methods. All the catalysts obtained had a similar crys-
Catal., A, 2013, 455, 107–113.
tallinity and Si/Al ratio. The variation of crystal morphology and 18 B. Yang, J. G. Jiang, H. Xu, Y. Liu, H. Peng and P. Wu,
size did not change the total number of acid sites, but the Microporous Mesoporous Mater., 2015, 203, 54–62.
decrease of crystal size increased the external surface area and 19 Y. Hu, L. Liu, H. Zhang, L. Hu, C. Zhang and H. Zhang, React.
mesopores, forming more pore mouth acid sites. In particular, Kinet., Mech. Catal., 2014, 112, 241–248.
nano-sized ferrierite, which showed more pore mouth acid sites 20 J. Houzvicka, O. Diefenbach and V. Ponec, J. Catal., 1996,
and better stability and higher activity, was synthesized using 164, 288–300.
pyrrolidine and TMAOH as double structure-directing agents 21 M. Guisnet, P. Andy, N. S. Gnep, E. Benazzi and C. Travers, J.
under dynamic crystallization. Moreover, we observed that the
Catal., 1996, 158, 551–560.
initial activity and isobutene selectivity in skeletal isomerization 22 D. M. Brouwer and H. Hogeveen, Prog. Phys. Org. Chem.,
of n-butene are related to the quantity and nature of acid and 1972, 9, 179–240.
conrmed that the monomolecular reaction mechanism 23 D. Jo, S. B. Hong and M. A. Camblor, ACS Catal., 2015, 5,
occurred on fresh ferrierite. Although high isobutene selectivity 2270–2274.
was obtained on fresh nano-sized ferrierite, better stability and 24 P. Andy, N. S. Gnep, M. Guisnet, E. Benazzi and C. Traversy,
higher selectivity required that carbonaceous materials modi- J. Catal., 1998, 173, 322–332.
ed the acid sites, suppressing the bimolecular reaction under 25 Y. P. Khitev, I. I. Ivanova, Y. G. Kolyagin and
ˇ
ˇ
a long stream time.
O. A. Ponomareva, Appl. Catal., A, 2012, 17, 124–135.
26 R. Anand, R. B. Khomane, B. S. Rao and B. D. Kulkarni,
Catal. Lett., 2002, 78, 189–194.
27 H. C. Lee, H. C. Woo, S. H. Chung, H. J. Kim, K. H. Lee and
J. S. Lee, J. Catal., 2002, 211, 216–225.
Notes and references
1 R. A. Sawichi, R. J. Pellet, D. G. Casey, R. V. Kessler,
H. M. Huang, C. L. O'-Young and E. J. Kuhlmann, 28 X. Li, X. Liu, S. Liu, S. Xie, X. Zhu, F. Chen and L. Xu, RSC
Hydrocarbon Eng., 1998, 3, 44–48.
Adv., 2013, 3, 16549–16557.
2 A. Corma, Chem. Rev., 1995, 95, 559–614.
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