Condensed‐Mode Cooling for Ethylene Polymerization: The Influence of Inert Condensing Agent on the Polymerization Rate
Condensed‐Mode Cooling for Ethylene Polymerization: The Influence of Inert Condensing Agent on the Polymerization Rate
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DOI：
10.1002/macp.201300757
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发表时间：
2014-05
影响因子：
2.5
通讯作者：
M. Namkajorn;A. Alizadeh;E. Somsook;T. McKenna
中科院分区：
文献类型：
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作者：
M. Namkajorn;A. Alizadeh;E. Somsook;T. McKenna
惰性冷凝剂（ICA）主要用于冷却气相流化床反应器，该反应器用于在负载型催化剂上重整乙烯。虽然这些ICA是化学惰性的，但似乎它们仍然可以增加聚合速率。正己烷被用作伊卡，并且观察到气相中乙烯聚合的瞬时速率的增强。这是由于在无定形聚合物中的乙烯的溶解度和扩散率的增加，在活性位点周围的无定形聚合物相中的局部乙烯浓度的上升。此外，随着正己烷浓度的增加，聚合物颗粒具有更光滑的表面，纤维状子结构的形成更少。
Inert condensing agents (ICAs) are used principally to cool down gas‐phase fluidized bed reactors used to polymerize ethylene over supported catalysts. While these ICAs are chemically inert, it appears that they might nevertheless increase the polymerization rate. n‐Hexane is used as an ICA, and an enhancement in the instantaneous rate of ethylene polymerization in the gas phase is observed. This is attributed to a rise in the local ethylene concentration in the amorphous polymer phase surrounding the active sites, due to increases in both the solubility and diffusivity of ethylene in the amorphous polymer. In addition, the polymer particles have a smoother surface with less formation of fiber‐like substructures as the n‐hexane concentration increases.