Vol. 27, No. 7 (2015)
Synthesis of Picolines Over Metal Modified HZSM-5 Catalyst 2419
2
1,22
reaction . The increasing amount of surface acidity may be
the reason for the high picoline yield, while the increasing
amount of weak acid sites are account for the unique selectivity
of 2-picoline.
5
5
4
4
5
0
5
0
Conclusion
Highly dispersed and MFI structure well reserved Pb, Cd,
Zn, Co, Cr modified ZSM-5 catalysts were obtained by the
ion-exchange method. The surface area and pore properties
were also showed small change after the modification. How-
ever, the amount of surface acidity, especially the weak acidity,
increased a great deal of the modified samples. Catalytic
experiments revealed that the metal incorporated catalysts gave
higher yields of pyridine bases than the original HZSM-5.
Among them, performance of Pb-ZSM-5 and Cd-ZSM-5 was
better than that of the rest catalysts in terms of yields of total
pyridine bases and selectivity of 2-picoline. The yields of pyri-
dine bases for Pb-ZSM-5 and Cd-ZSM-5 were 84.1 % and
36
32
28
24
20
16
73.2 %, respectively and the selectivity of 2-picoline were 56.3
and 58.6 %, respectively. However, the coking of the metal
incorporated catalysts was worse than the initial zeolite, which
may be due to the restriction of diffusion of the products after
modification. Moreover, the coking of Pb-ZSM-5 was the least
among the modified samples which also gave the highest yield
of pyridine bases.
1
2
3
4
5
6
7
8
Time on stream (h)
Fig. 7. Yield and selectivity of 4-picoline versus time on stream. (a) H-
ZSM-5, (b) Co-ZSM-5, (c) Pb-ZSM-5, (d) Zn-ZSM-5, (e) Cr-ZSM-
5, (f) Cd-ZSM-5
ACKNOWLEDGEMENTS
The authors thank the National Natural Science Foundation
of China (21276050) and the Scientific Research Foundation
of Graduate School of Southeast University (YBJJ1341).
The ratios of all the metal incorporated catalyst are higher
than that of H-ZSM-5 (0.75-0.82) in addition to that of Mg-
ZSM-5 catalyst at the reaction carrying on 2 and 5 h. Ion-
exchange treatment increases the selectivity of 2-picoline but
decreases that of 4-picoline.
REFERENCES
1
2
3
.
.
.
S. Golunski and D. Jackson, Appl. Catal., 23, 1 (1986).
S. Shimizu, N.Abe,A. Iguchi and H. Sato, Catal. Surv. Jpn., 2, 71 (1998).
J.R. Calvin, R.D. Davis and C.H. McAteer, Appl. Catal., 285, 1 (2005).
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
4. S. Shimizu, N.Abe,A. Iguchi, M. Dohba, H. Sato and K. Hirose, Micropor.
Mesopor. Mater., 21, 447 (1998).
5
6
.
.
Y. Liu, H.Yang, F. Jin,Y. Zhang andY. Li, Chem. Eng. J., 136, 282 (2008).
R. Rao, S. Kulkarni, M. Subrahmanyam andA. Rao, React. Kinet. Catal.
Lett., 56, 301 (1995).
7
8
.
.
K. Reddy, I. Sreedhar and K. Raghavan, Appl. Catal. A, 339, 15 (2008).
K. Iwamoto and T. Shoji, US Patent 6281262B1 (2001).
9. A. Agarwal, P. Verma and K. Singh, US Patent 20050131235A1 (2005).
1
0. B. Singh, S.K. Roy, K.P. Sharma and T.K. Goswami, J. Chem. Technol.
Biotechnol., 71, 246 (1998).
11. L.B. Pierella, C. Saux, S.C. Caglieri, H.R. Bertorello and P.G. Bercoff,
Appl. Catal. A, 347, 55 (2008).
1
1
2. M. Niwa and Y. Murakami, Phys. Chem. Solids, 50, 487 (1989).
3. M. Niwa, Y. Kawashima andY. Murakami, Chem. Soc. Farad. Trans. I,
1
2
3
4
5
6
7
8
8
1, 2757 (1985).
Time on stream (h)
Fig. 8. 2-Picoline/4-picoline ratio versus time on stream. (a) H-ZSM-5,
b) Co-ZSM-5, (c) Pb-ZSM-5, (d) Zn-ZSM-5, (e) Cr-ZSM-5, (f)
1
1
1
1
4. F. Jin, Y.G. Cui and Y.D. Li, Appl. Catal. A, 350, 71 (2008).
5. K.Yamagishi, S. Namba and T.Yashima, J. Phys. Chem., 95, 872 (1991).
6. F. Jin, G. Wu and Y. Li, Chem. Eng. Technol., 34, 1660 (2011).
7. G. Coudurier, C. Naccache and J.C. Vedrine, J. Chem. Soc. Chem.
Commun., 24, 1413 (1982).
(
Cd-ZSM-5
All these results discussed above show that the yield of
pyridine bases can be greatly enhanced by the introduction
metal ion into the ZSM-5 zeolite. These metal modified
samples, especially Pb-ZSM-5 and Cd-ZSM-5 sample, not
only enhances the yield of picolines, but also has a unique
selectivity to 2-picoline. This may be due to the change of
distribution of surface acidity, which is a very important factor
influencing the catalytic activity and selectivity in Chichibabin
18. C.S. Triantafillidis, A.G. Vlessidis, L. Nalbandian and N.P. Evmiridis,
Micropor. Mesopor. Mater., 47, 369 (2001).
1
2
9. S.C. Luo and J. Falconer, Catal. Lett., 57, 89 (1999).
0. A. Sile, A. Avots, I. Ioffe and M. Shimanskaya, Geter. Katal. Reakts.
Poluch. Prevashch. Getero. Soedin., 169 (1971).
21. S. Kulkarni, R. Rao, M. Subrahmanyam and A. Rao, Appl. Catal., 113,
(1994).
2. H. Sato, S. Shimizu, N. Abe and K. Hirose, Chem. Lett., 23, 59 (1994).
1
2