Phillips catalyst, polyolefin manufacture

All heterogeneous Ziegler-Natta and Phillips catalysts have two or more active-site types and many soluble Ziegler-Natta and metallocene catalysts may also show multiple-site behavior [36, 37]. In addition, several metallocene catalysts, when supported on organic and inorganic carriers, may behave like multiple-site catalysts even if they behaved as single-site catalysts in solution polymerization. Therefore, several of the catalysts used industrially for polyolefin manufacturing have in fact two or more active-site types. 

Most commercial processes for the manufacture of polyolefins use solid catalysts, such as heterogeneous Ziegler-Natta and Phillips catalysts. Many metallocene catalysts have also been supported on inorganic carriers, typically silica, for industrial... 

Slurry polymerization is often used in the manufacture of polyolefins. Initially, the reaction system consists of the catalyst dispersed (or dissolved as in the case of soluble metallocene catalysts) in a continuous medium, which may be a diluent in which the monomer is dissolved or pure monomer. The polymer is insoluble in the continuous medium, therefore it precipitates on the catalyst forming a slurry. High-density polyethylene (HOPE) is produced in a slurry of isobutane (Chevron-Phillips process) [22 ]. Liquid propylene is used in the Spheripol process to produce i-PP [22]. 

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