(513a) CON-Type Zeolite: A New Type of Catalyst for the MTO Reaction

The Methanol to Olefins (MTO) reaction has received much attention because this reaction might be the most practical process to provide lower olefins, which are important chemicals for the polymer industry instead of steam cracking [1]. Various zeolites have been investigated as a solid acid catalyst for the MTO reaction; there are numerous reports on the modifications of catalysts to promote the transformation of methanol and to control the selectivity to the desired products. The high yield of olefins obtained from SSZ-13 and SAPO-34 catalyst is usually explained by its 8-membered ring (8-MR) pores and relatively weak acidity, whereas the advantage of ZSM-5 is its excellent resistance to coking despite the low selectivities to C2-C3 olefins, e.g. ethene and propene.

Nowadays fundamental chemical materials required from chemical industry have been shifted from C2-C3 to C3-C4 olefins like propene and butenes.  Hence, small-pore zeolites do not meet this demand and the development of the zeolite catalyst that can produce selectively C3-C4 olefins by the conversion of methanol has been strongly desired.  Thus, we have adopted 12MR zeolites with 3-dimensional channels as catalysts for the MTO reaction to achieve the selective production of C3-C4 olefins and the long catalytic life. Hence, we have focused on the preparation of the CON-type zeolites[2], which consists of 3-dimensional channel system with 12-, 12- and 10-MR pores, as catalyst for the MTO reaction.

Here, we first report on the preparation of Al-containing CON-type zeolites and their excellent catalytic performance in the MTO reaction; it exhibited a high propene selectivity and a long catalytic life because the high diffusibility due to the CON structure suppressed sequential reactions and the following coke formation.

1. Olsbye, U.; Svelle, S.; Bjørgen, M.; Beato, P.; Janssens, T. V. W.; Joensen, F.; Bordia, S.; Lillerud, K. P. Angew. Chem. Int. Ed. 2012, 51, 5810-5831.
2. Lobo, R. F.; Davis, M. E. J. Am. Chem. Soc. 1995, 117, 3766-3779.