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Depelopment of supported catalysts for living polymerization of olefins and its application to gas-phse polymerization

负载型烯烃活性聚合催化剂的研制及其在气相聚合中的应用

基本信息

批准号：
15360419
负责人：
SHIONO Takeshi
金额：
$ 6.66万
依托单位：
HIROSHIMA UNIVERSITY (2004-2005)Tokyo Institute of Technology (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The living polymerization, therefore, has attracted much attention and several papers have reported on the living polymerization of propene by homogeneous catalytic systems. There are, however, few examples for living polymerization of propene by supported single-site catalytic systems, which should be very important from the practical point of view. We have previously found that living polymerization of propene proceeded in heptane at 0℃ by a chelating (diamide) dimethyltitaniumcomplex (1) activated with trialkylaluminum-free modified methylaluminoxane (dMMAO), which is easily soluble in hydrocarbons.We prepared supported dMMAOs using silica gel, alumina and magnesia by the reaction of the support and dMMAO in heptane and conducted propene polymerization with 1 to clarify the supporting effects of dried MMAO. The supported systems conducted living polymerization of propene at 0℃ without any induction period regardless of the metal oxides for dried MMAO. The propagation rate constants (k_p) of these systems and the molecular weight distribution (M_w/M_n) of the produced polymer depended on the metal oxide employed. The k_p value increased with the increase in Lewis acidity of MMAO on the support and the broadening (M_w/M_n) was ascribed to the distribution of Lewis acidity caused by the heterogeneity of the supported cocatalyst. The systems gave atactic polypropylene regardless of the metal oxides for dried MMAO.We also conducted propene polymerization with ansa-fluorenylamidodimethyltitanium (2), which conducts living polymerization of propene when activated with dMMAO, in place of 1. Although the 2-supported dMMAO systems of silica-gel and alumina showed very high initial activity, the system deactivated and chain transfer also occurred. The results indicated that the combination of the complex and the supported activator was very important for the living polymerization with supported catalytic systems.

因此，活性聚合引起了人们的广泛关注，并且有几篇论文报道了均相催化体系的丙烯活性聚合。然而，通过负载型单中心催化体系进行丙烯活性聚合的例子很少，从实用的角度来看，这应该非常重要。我们之前发现，丙烯在0℃庚烷中通过用易溶于烃类的无三烷基铝的改性甲基铝氧烷（dMMAO）活化的螯合（二酰胺）二甲基钛配合物（1）进行活性聚合。我们利用硅胶、氧化铝和氧化镁，通过载体与 dMMAO 在庚烷中并与 1 进行丙烯聚合，以阐明干燥 MMAO 的支撑作用。无论干燥MMAO的金属氧化物如何，负载体系在0℃下进行丙烯活性聚合，无需任何诱导期。这些系统的增长速率常数 (k_p) 和生成的聚合物的分子量分布 (M_w/M_n) 取决于所使用的金属氧化物。 k_p值随着载体上MMAO路易斯酸度的增加而增加，并且展宽（M_w/M_n）归因于负载助催化剂的异质性引起的路易斯酸度分布。无论干燥MMAO的金属氧化物如何，该系统都会产生无规聚丙烯。我们还用反芴酰氨基二甲基钛(2)进行丙烯聚合，当用dMMAO活化时，代替1，它会进行丙烯的活性聚合。虽然硅胶和氧化铝的2负载dMMAO系统显示出非常高的初始活性，但该系统失活并且还发生链转移。结果表明，配合物与负载型活化剂的结合对于负载型催化体系的活性聚合非常重要。