The influence of phenylsilane on the syndiotactic polymerization of styrene with ?5-pentamethylcyclopentadienyl titanium trifluoride
The influence of phenylsilane on the syndiotactic polymerization of styrene with ?5-pentamethylcyclopentadienyl titanium trifluoride
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DOI：
10.1002/1099-0518(20001001)38:19
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发表时间：
2000-10
期刊：
影响因子：
--
通讯作者：
J. Schellenberg;T. Newman
中科院分区：
文献类型：
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作者：
J. Schellenberg;T. Newman
在单体中加入摩尔比为2 0 0/1的甲基铝氧烷(MAO；MAO/CP*TIF3摩尔比=2 0 0/1)和三异丁基铝时，η6-五甲基环戊二烯基三氟化钛(CP*TIF3)的间规聚苯乙烯聚合活性可通过加入摩尔比约为30 0/1~6 0 0/1的苯基硅烷显著提高。与不含苯基硅烷的苯乙烯相比，较低的苯基硅烷用量，如与Cp*TiF3的摩尔比为100/1，导致聚合活性降低。苯基硅烷与催化剂混合物的预反应表现出强烈依赖于组分的储存时间和温度的行为。大约16小时的储存时间足以将聚合转化率降低到原始值的大约一半。根据与苯基硅烷的链转移反应和几种不同稳定性和活性的催化剂络合物，包括苯基硅烷的烷基化产物，对结果进行了讨论。
The syndiotactic polystyrene polymerization activity of a fluorinated half-sandwich complex, η 6 -pentamethylcyclopentadienyl titanium trifluoride (Cp * TiF 3 ), in the presence of relatively low amounts of methylalumoxane (MAO; MAO/Cp * TiF 3 molar ratio = 200/1) and triisobutylaluminum, is significantly increased by the addition of phenylsilane in molar ratios to Cp * TiF 3 ranging from about 300/1 to 600/1, if the phenylsilane is added to the monomer. Lower amounts of phenylsilane, such as a 100/1 molar ratio to Cp * TiF 3 , lead to a reduced polymerization activity in comparison with styrene without phenylsilane. A prereaction of phenylsilane with the catalyst mixture shows a behavior that is strongly dependent on the storage time of the composition and the temperature. A storage time of about 16 h is sufficient to reduce the polymerization conversion to about half of the original value. The results are discussed on the basis of a chain-transfer reaction with phenylsilane and several catalyst complexes of different stabilities and activities, including an alkylation product of phenylsilane.