(560dr) Assessing the Role of Zr-Al Interactions in Oxide-Grafted Zr Precursors for Ethylene Oligomerization Reactions | AIChE

(560dr) Assessing the Role of Zr-Al Interactions in Oxide-Grafted Zr Precursors for Ethylene Oligomerization Reactions

Authors 

Magazova, G. - Presenter, University of Notre Dame
Wright, J. D., University of Notre Dame
Schneider, W., University of Notre Dame
Hicks, J., University of Notre Dame

Assessing the role of Zr-Al
interactions in oxide-grafted Zr precursors for ethylene
oligomerization reactions

Galiya Magazova, Joshua D.
Wright, Neha Mehra, William F. Schneider, and Jason
C. Hicks*

Department of Chemical and Biomolecular Engineering,
University of Notre Dame, 182 Fitzpatrick Hall, Notre Dame, IN 46556

Many Group IV transition metal catalysts have been
reported to selectively dimerize or trimerize ethylene.   However, these homogeneous catalysts 1) require
an expensive co-catalyst, 2) are difficult to separate from reaction media and
require significant reactor/reaction engineering for continuous operation in a
flow reactor, and 3) are not thermally stable to temperatures > 300 oC in many cases.   In this presentation, we will discuss our ongoing
hypothesis that Group IV catalysts grafted on a solid support can grow ethylene
chains effectively while avoiding liquid-based activating agents.  We also hypothesize that the interaction
between the grafted Zr species and the support is
essential in providing a suitable active center for oligomerization. 

It was recently reported that zirconium hydride catalysts
supported on dehydroxylated silica-alumina are selective for 2–butene
dimerization.1 We will report our findings on the appropriate
synthesis conditions required for the effective oligomerization of ethylene by
grafted zirconium species in the absence of an added co-catalyst. Background
oligomerization activity is observed with the silica-alumina support.  However, the grafted and H2
activated zirconium species enhance the reactivity by a factor of two. The
product distribution follows a Flory-Schulz distribution, with dimers as the major
products followed by trimers and heavier hydrocarbons. The ethylene consumption
rate increases with an increase in the zirconium loading on the support, which
indicates that zirconium centers play a role in activating ethylene.  However, without the presence of Al in the
oxide support, no activity is observed, which implies a cooperative or
synergistic relationship between Zr and Al.  Therefore, we will also show the correlation
between the Zr/Al ratio and the catalytic performance. 

References

(1)  Szeto, K.C.; Merle, N.; Rios, C.; Rouge, P.; Castelbou, J.L.; Taoufik, M. Catal. Sci. Technol. 2015, 5, 4765.