Novel Methods to Synthesize ZSM-11 As an Efficient Catalyst for Methanol-to-Hydrocarbon Reactions

ZSM-11 (MEL) is an emerging catalyst for a wide variety of applications. The MEL framework is similar to ZSM-5 (MFI), which is one of the most widely used zeolite catalysts in industry. Recent studies have shown that ZSM-11 performs better as a catalyst in several different reactions compared to ZSM-5 [1-3], possibly due to improved intra-crystalline diffusion within the less-tortuous straight channels of the MEL topology. However, there are relatively few systematic studies of ZSM-11 synthesis, specifically with respect to tailored physicochemical properties such as size, shape, and composition (i.e., Si/Al ratio, or SAR). Moreover, MEL is conventionally synthesized using tetrabutylammonium (TBA) as an organic structure-directing agent (OSDA), which is costly and yields ZSM-11 crystals with ZSM-5 impurity [4]. Here, we will present methods to prepare ZSM-11 catalysts as well as the results of testing for methanol-to-hydrocarbon (MTH) reactions. Through the judicious selection of synthesis parameters, we successfully developed a facile protocol to prepare ZSM-11 catalysts with sub-micron crystal size, high MEL phase purity, low OSDA usage, and tunable SAR. The ZSM-11 catalyst samples synthesized via these novel methods showed significantly improved catalyst lifetime in MTH reactions compared to those synthesized by conventional methods.

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[3] Bleken, F.; Skistad, W.; Barbera, K.; Kustova, M.; Bordiga, S.; Beato, P.; Lillerud, K. P.; Svelle, S.; Olsbye, U., Physical Chemistry Chemical Physics 2011, 13 (7), 2539-2549.

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