Organic Superbase as an Efficient Catalyst for Group Transfer Polymerization of Methyl Methacrylate
Organic Superbase as an Efficient Catalyst for Group Transfer Polymerization of Methyl Methacrylate
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DOI：
10.1021/ma200720p
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发表时间：
2011-06-28
期刊：
影响因子：
5.5
通讯作者：
Satoh, Toshifumi
中科院分区：
文献类型：
--
作者：
Kakuchi, Toyoji;Chen, Yougen;Satoh, Toshifumi
有机超碱，1，8-二氮双环[5.4.0]undec-7-ene(DBU)，前氮磷杂环(P(RNCH2CH2)(3)-N：R=CH3，TMP；R=i-Bu，TiBP)，和磷腈碱(1-tert-butyl-2，2，4，4，4-pentakis(dimethylamino)-2(5)，4-Lambda(5)-Catenadi(磷腈)，t-Bu-P-2；用1-tert-butyl-4，4，4-tris(dimethylamino)-2，2-bis[tris(dimethylamino)phosphoranylidenamino]-2-Lambda(5)，4-Lambda(5)-Catenadi(磷腈)，t-Bu-P-4考察了它们在甲基丙烯酸甲酯基团转移聚合反应中的催化活性。在所使用的超强碱中，TiBP和t-Bu-P-4有效地催化了聚合反应，得到了相对分子质量可控、多分散性较窄的聚甲基丙烯酸甲酯(PMMA)。由r-Bu-P-4催化的GTP得到的PMMA的相对分子质量高达109 600gmol(-1)。从TiBP和t-Bu-P-4催化的GTP得到的PMMA的MALDI-TOF MS谱中只有一系列峰，表明这两种聚合过程都没有任何副反应。后聚合实验进一步支持了TiBP和t-Bu-P-4催化的MMA GTP的活性。此外，通过测定得到的PMMA的立构规整度并获得了MTS与TiBP或t-Bu-P-4等摩尔混合物的一系列核磁共振谱，对TiBP和t-Bu-P-4催化的MMA GTPS进行了机理研究。
Organic superbases, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), proazaphosphatranes (P(RNCH2CH2)(3)-N: R = CH3, TMP; R = i-Bu, TiBP), and phosphazene bases (1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2 Lambda(5),4 Lambda(5)- catenadi(phosphazene), t-Bu-P-2; 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2 Lambda(5),4 Lambda(5)-catenadi(phosphazene), t-Bu-P-4) were employed to determine the catalytic activity in the group transfer polymerization (GTP) of methyl methacrylate (MMA). Among the superbases used, TiBP and t-Bu-P-4 effectively catalyzed the polymerization to afford poly(methyl methacrylate) (PMMA) with controlled molecular weight and narrow polydispersity. In particular, the molecular weight of the PMMA obtained from the r-Bu-P-4-catalyzed GTP was up to 109 600 g mol(-1). Only one series of peaks was observed in the MALDI-TOF MS spectra of the PMMAs obtained from the TiBP- and t-Bu-P-4-catalyzed GTPs, indicating that both polymerizations proceeded without any side reactions. A postpolymerization experiment further supported the living nature of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA. Furthermore, a mechanistic study of the TiBP- and t-Bu-P-4-catalyzed GTPs of MMA was attempted by determining the stereoregularity of the obtained PMMAs and obtaining a series of NMR spectra for the equimolar mixtures of MTS and TiBP or t-Bu-P-4.