Norbornadiene homopolymerization and norbornene/norbornadiene/1-octene terpolymerization by ansa-fluorenylamidotitanium-based catalysts
Norbornadiene homopolymerization and norbornene/norbornadiene/1-octene terpolymerization by ansa-fluorenylamidotitanium-based catalysts
复制标题
DOI：
10.1039/d0py01180k
复制
发表时间：
2020-11
影响因子：
4.6
通讯作者：
Hongyi Suo;Haobo Yuan;R. Tanaka;Y. Nakayama;Wen‐Hua Sun;T. Shiono
中科院分区：
文献类型：
--
作者：
Hongyi Suo;Haobo Yuan;R. Tanaka;Y. Nakayama;Wen‐Hua Sun;T. Shiono
采用ansa-芴酰胺钛配合物Me2Si(Flu)(NtBu)TiMe2(1)和Me2Si(2,7- tbu2flu)(NtBu)TiMe2(2)作为预催化剂，进行了降冰片二烯（NBD）的均聚合以及NBD、降冰片二烯（NB）和1-辛烯（OC）的共聚合。在NBD均聚反应中，催化剂2在改性甲基铝氧烷（MMAO）活化下的转化率是催化剂1的两倍，所得聚合物的分子量是催化剂1的两倍以上。将助催化剂由MMAO改为[Ph3C][B(C6F5)4]，转化率和分子量均有显著提高。2-[Ph3C][B(C6F5)4]在25℃和0℃条件下聚合10 min后，转化率分别为52%和62%。在0℃条件下反应1 h，转化率达到82%，制得数平均分子量（Mn）为34 100的可溶性聚合物nbd。在4种预催化剂/助催化剂组合中，2-[Ph3C][B(C6F5)4]催化体系对NBD/NB/OC的共聚合效果最好，在0℃条件下聚合10 min后，得到Mn = 66 300， NBD质量分数为13 mol%，转化率为64%的三元共聚物。所有得到的聚合物都具有良好的溶解度，表明通过NBD衍生的NB单元的交联可以忽略不计。
ansa-Fluorenylamidotitanium complexes Me2Si(Flu)(NtBu)TiMe2 (1) and Me2Si(2,7-tBu2Flu)(NtBu)TiMe2 (2) were used as precatalysts for the homopolymerization of norbornadiene (NBD) and the terpolymerization of NBD, norbornene (NB), and 1-octene (OC). In the NBD homopolymerization, catalyst 2 showed double the conversion and yielded a polymer having more than double the molecular weight compared with catalyst 1 when activated by modified methylaluminoxane (MMAO). The conversion and molecular weight were significantly increased by changing the cocatalyst from MMAO to [Ph3C][B(C6F5)4]. The conversion levels after 10 min polymerization using 2-[Ph3C][B(C6F5)4] at 25 and 0 °C were 52% and 62%, respectively. The conversion reached 82% at 0 °C after 1 h, and soluble polyNBD with a number-average molecular weight (Mn) of 34 100 was obtained. The 2-[Ph3C][B(C6F5)4] catalytic system also showed the best performance for NBD/NB/OC terpolymerization among the four combinations of precatalyst/cocatalyst and gave the terpolymer with Mn of 66 300 containing 13 mol% of NBD at 64% conversion after 10 min polymerization at 0 °C. All resulting polymers possessed good solubility, indicating that crosslinking via the NB unit derived from NBD was negligible.