catalysts Article Comparison of Support Effects on Phillips and Metallocene Catalysts Qing Yang and Max Paul McDaniel * Chevron Phillips Chemical Co., Bartlesville, OK 74006, USA;
[email protected] * Correspondence:
[email protected] Abstract: Both metallocene and Phillips chromium catalysts are used in the commercial manufacture of polyethylene. Unlike most other commercial metallocene systems, the Chevron Phillips Chemical (CPC) platform does not use methylaluminoxane or fluoroorganic boranes. Instead, the support itself serves to activate (ionize) the metallocenes, which then polymerize ethylene at high activity. Most of these solid acid supports can also be used to anchor Cr to make a Phillips catalyst. This provides an interesting opportunity to compare the polymerization responses by these two disparate systems, Phillips Cr and CPC metallocene, when supported on the same solid acid carriers. In this study, both chromium oxide and several metallocenes were deposited onto a variety of solid oxides, under a variety of conditions, and the resulting support effects were observed and compared. Although using seemingly different chemistries, the two catalyst systems exhibited a surprising number of similarities, which can be attributed to the acidity and porosity of these diverse supports. Keywords: ethylene polymerization; Phillips catalyst; Cr/silica; solid acid; metallocene activation; long-chain branching Citation: Yang, Q.; McDaniel, M.P. Comparison of Support Effects on Phillips and Metallocene Catalysts. 1. Introduction Catalysts 2021, 11, 842. https:// Upon first reflection, one might not expect the chemistry of Phillips versus metallocene doi.org/10.3390/catal11070842 catalysts to have much in common. The former is entirely inorganic [1] whereas the latter is mostly, and often totally, composed of organometallic ingredients.