| 摘要 |
<p>The invention concerns a process for producing propylene, and polypropylenes produced thereby. According to the process, propylene is homo- or copolymerized in a reaction sequence including at least one bulk reaction zone and at least one gas phase reaction zone arranged in series. The polymerization is carried out in the presence of a Ziegler-Natta type catalyst system including a catalyst component, a cocatalyst component and an external donor. According to the invention the catalyst component, the external donor and a part of the cocatalyst component are fed to a first reaction zone, and the rest of said cocatalyst component is fed to a second reaction zone.</p> |
