The polymerization of ethylene with high activity magnesium reduced titanium trichloride catalysts in the absence of hydrogen – A statement of priorities

✍ Scribed by Tornqvist, Erik G. M.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1976
• Weight: 148 KB
• Volume: 177
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1976.021771125

✦ Synopsis

In a recent article entitled "The Polymerization of Ethylene with High Activity Magnesium Reduced Titanium Trichloride Catalysts in the Absence of Hydrogen", Boucher, Parsons, and Haward" make some introductory remarks, which, if left uncorrected, will give a wrong idea of the origin of some of the industrially most widely used catalysts for propylene polymerization.

After having mentioned that "effective titanium trichloride catalysts . . . do not consist of pure TiCI3", the authors claim that Natta et aL2) recognized that their (writer's emphasis) TiC13 contained 0,3mol AlC13 for each mol of TiC13. They then proceed with the statement that more recently (writer's emphasis) Tornquist et al.3,4) have studied the blending of TiC13 and AlC13 crystals and have shown that activity is increased by the incorporation of AlC13.

In reality, Natta et al. began their studies of olefin polymerizations with Ziegler-type catalysts many years before the date indicated by Boucher et al. Although they started their studies with conventional TiC14-based Ziegler catalysts, they soon discovered that considerably better results were obtained in alpha-olefin polymerizations with catalysts based on TiC135). Subsequent to this discovery and in short order a large number of publications followed in which catalyst systems based on hydrogen reduced TiCI3 were employed, among others for polymerization of propylene6). To be sure, there is one article by Natra et al.7) from this time-whic' mentions that TiC13 prepared by aluminium reduction according to the method of Ruff and Neumann"