(337c) Structure-Property Relationships for Unidimensional, Large and Extra-Large Pore Zeolites Using Alkane Hydrocracking and Hydroisomerization As Probe Reactions

Authors: 
Cybulskis, V., Purdue University
Zones, S. I., Chevron Energy and Technology Company
Davis, T., Chevron Energy Technology Company
Deem, M. W., Rice University
Davis, M. E., California Institute of Technology

Structure-Property
Relationships for Unidimensional, Large and Extra-Large Pore Zeolites Using
Alkane Hydrocracking and Hydroisomerization as Probe Reactions

Viktor
J. Cybulskis1, Stacey I. Zones2, Tracy M.
Davis2, Cong-Yan Chen2, Michael W. Deem3 and
Mark E. Davis1

1Chemical
Engineering, California Institute of Technology, Pasadena, CA 91125, USA

2Chevron
Energy Technology Company, Richmond, CA 94802, USA

3Bioengineering,
Rice University, Houston, TX 77005 USA

High-silica
zeolites (Si/Al > 30) are versatile catalytic materials in petroleum
refining processes due to their thermal stability, shape selectivity, and
chemical functionality. However, of the 232 known [1] and more than 330,000
predicted [2] zeolite structures, the global refining market is dominated by
five main frameworks: FAU, MOR, MFI, *BEA and FER [3]. While these zeolites
often deliver satisfactory commercial performance, the development of materials
with improved function or entirely new structures for future applications requires
a deeper understanding of how specific properties, such as composition,
framework topology, and acid site function, can influence the product
distribution for a given reaction.

For
the present study, large and extra-large pore zeolites were prepared from the corresponding
structure-directing agents (SDAs) shown in Table 1 to investigate the effects
of the organo-cation guest molecules and synthesis
conditions on zeolite crystallinity, microporosity, and heteroatom incorporation.
Unidimensional (1D) structures were chosen so that the zeolite pore opening could
be used to adequately describe the confining size. Hydrocracking and
hydroisomerization of n-hexane (nC6) and n-decane (nC10)
were used as probe reactions on these Pt-exchanged, 12- and 14-membered ring
(MR) zeolites to examine the effect of pore structure on shape selectivity by
comparing the distributions and yields of branched C6 and C10
isomers. Elucidation of these structure-property relations support de novo computational design efforts to predict
chemically-synthesizable SDAs and produce a novel, 1D zeolite framework with tailored
catalytic properties.

Table 1. 1D,
12- and 14-MR zeolites synthesized from the corresponding SDAs

References:

[1]       C. Baerlocher and L.B. McCusker, Database
of Zeolite Structures, http://www.iza-structure.org/databases/. Accessed March 27,
2017 (2017).

[2]       R. Pophale, P.A. Cheeseman and M.W. Deem, Phys. Chem. Chem. Phys. 13, 12407 (2011).

[3]       W. Vermeiren and J.P. Gilson, Top. Catal. 52, 1131 (2009).