(629s) Synthesis of Mesoporous Aluminosilicates From Commercially Available Ferrierite and Application for Catalytic Reaction

A new synthesis strategy has been reported for ordered mesoporous materials constructed with semi-zeolitic frameworks and high aluminium contents using commercial zeolites such as beta, ZSM-5, USY and mordenite as a source for framework through a simple way combining top-down and bottom-up approaches [1,2]. However, results about the mesoporous substance with ferrierite framework are not known yet.

1-Butene is widely used as a monomer to produce polybutene and a comonomer for copolymerization in production of polyethylene. Recently, its demand has been raised and its price has been increased by price increase of petroleum. Currently, 1-butene is produced through separation processes from C₄ fractions in the naphtha cracking centre of a petrochemical plant and in the refinery plants. When these processes are completed, C₄ raffinate-III containing lots of 2-butene is remained and currently, it is used as a cheap fuel by transforming it into butane through hydrogenation. Therefore, it is necessary to convert 2-butene into more valuable 1-butene by positional isomerization. However, there is yet no commercial process producing 1-butene through positional isomerisation of 2-butene, and there are only a few research results about it. According to the previous reports, the catalysts, which have fewer and weaker Brönsted acid sites as well more Lewis acid sites, are quite useful for the positional isomerisation from 2-butene to 1-butene. Previously, we found that MCM-41, which has a very weak acid site, sufficiently performs a role as a catalyst in positional isomerization of 2-butene [3,4].

In this study, we demonstrate a synthesis method for ordered mesoporous materials constructed with ferrierite framework (MMZ-FER) and the applicability as catalyst for the positional isomerisation from 2-butene to 1-butene. The synthesis method involves combination of top-down and bottom-up approaches using commercially available ferrierite and cationic surfactant as the framework source and the structure directing agent respectively. The mesoporous materials from ferrierite is produced by disassembling ferrierite into unit structure in the presence of alkali solution, adding a surfactant as a templating material and performing hydrothermal synthesis. It also analyzed the effect of diverse variables in preparation of the mesoporous materials from ferrierite on the characteristics of catalyst and performance of isomerization of 2-butene.

When producing MMZ-FER through hydrothermal reaction after dissolving commercial ferrierite in NaOH solution and adding it to CTAB solution, the optimal concentration of NaOH was 0.67 – 1.3 N to contain mesopores and to keep characteristics of FER simultaneously. It was confirmed successful formation of well-ordered meso structure in the manufacturing process of mesoporous zeolite substance by dissolving commercial FER in alkali solution to make precursor solution. This catalyst had decreased amount of Brönsted acid site of FER and increased amount and intensity of weak acid site. In addition, it was identified that MMZ-FER with FER structure and mesopore structure is a superior catalyst for activity, selectivity and lifetime in positional isomerization of 2-butene.

 References

[1] H. I. Lee, H. J. Park, Y. K. Park , J. Y. Hur, J. K. Jeon, J. M. Kim, Catal. Today, 2008, 132, 68.

[2] H. J. Park, J. K. Jeon, J. M. Kim, H. I. Lee, J. H. Yim, J. Park, and Y. K. Park, J. Nanosci. Nanotech., 2008, 8, 5439.

[3] J. K. Jeon, H. Lee, J. H. Yim, Y. S. Kim, S. J. Lee, Y. K. Park, J. K. Shon and J. M. Kim, Catal. Lett., 2007, 119, 179.

[4] N. You, J. H. Yim, S. J. Lee, J. H. Lee, Y. K. Park and J. K. Jeon, J. Nanosci. Nanotech., 2007, 7, 3800.