The roles of Grignard reagent in the Ziegler–Natta catalyst for propylene polymerization

✍ Scribed by Junting Xu; Linxian Feng; Tao Xie; Shilin Yang

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 148 KB
• Volume: 65
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970801)65:5<925::aid-app10>3.0.co;2-r

✦ Synopsis

Grignard reagent PhMgCl was added during the preparation of the catalyst system MgCl 2 /di-n-butyl phthalate (DNBP)/TiCl 4 {AlEt 3 /diphenyl dimethoxyl silane (DPDMS) to improve its performance. It was found that PhMgCl could enhance both the activity of the catalyst and the isotacticity of the products, but decreased the Ti content of the catalysts under the same preparation conditions. The polymerization kinetics showed that PhMgCl accelerates the decay in the same time that it increased the initial and final polymerization rates. By means of UV-vis spectroscopy, electron spin resonance (ESR) spectroscopy, and the Ti content determination of the catalysts, the multiple roles of PhMgCl were disclosed: reduction of Ti 4/ to Ti 3/ , association with MgCl 2 to replace part of TiCl 4 in aspecific active sites, and complexing with the original active sites to form new active sites.