Synthesis of End-Reactive Monodisperse Polyamides by Living Anionic Polymerization of beta-Lactams

在25 ℃，含5wt%氯化锂的N，N-二甲基乙酰胺中，实现了3，3-二甲基-和4，4-二甲基-2-氮杂环丁酮两种甲基取代β-内酰胺的活性阴离子聚合，并在均相中定量进行。从凝胶渗透色谱法发现所得聚酰胺具有窄的分子量分布。根据1H-NMR谱中的峰强度估计的数均分子量几乎等于根据消耗的内酰胺与用作活化剂的相应N-苯甲酰基衍生物的摩尔比计算的数均分子量。此外，聚合后，通过与苄胺的反应，酰基内酰胺型增长链端被定量地修饰。为了实现内酰胺的活性阴离子聚合，除了氮原子上没有活性氢的高活性内酰胺应该在温和的条件下聚合。在目前的调查中，我们尝试了 ...更多信息 三种β-内酰胺，即3，3-二甲基-、4，4-二甲基-和3-甲基-2-氮杂环丁酮（分别为1、2和3）的活性阴离子聚合，得到单分散聚酰胺。它们的聚合分别使用相应的N-苯甲酰基内酰胺和吡咯烷酮钾作为活化剂和催化剂，在25 ℃下，N-二甲基乙酰胺（DMAc）与氯化锂（LiCl）在均相中进行反应。用含LiCl的DMAc作洗脱剂，用GPC测定了由1和2得到的聚酰胺的分子量分布（Mw/Mn <1.1）。由3制备的聚酰胺的M_W/M_n值为1.2-1.3，但聚合过程中没有观察到终止。从相应的酰基内酰胺的氨解的动力学分析的结果，加宽被推测主要是由引发反应常数的比率在3的阴离子聚合中的传播一个低值引起的。少

Living anionic polymerization of two kinds of methyl-substituted beta-lactams, 3, 3-dimethyl-, and 4, 4-dimethyl-2azetidinones, was attained at 25ﾟC in N, N-dimethylacetamide containing 5 wt% of lithium chloride and proceeded in a homogeneous phase quantitatively. The resulting polyamides were found to have a narrow molecular weight distribution from the gel permeation chromatography. The number average molecular weights estimated from the peak intensities in the ^1H-NMR spectra were almost equal to those calculated from the mole ratio of the consumed lactam to the corresponding N-benzoyl derivative used as an activator. In addition, the acyllactam-type growing chain ends were modified quantitatively by the reaction with benzylamine after the polymerization.In order to attain the living anionic polymerization of lactams, highly reactive lactams having no active hydrogen except on the nitrogen atoms should be polymerized under mild conditions. In the present investigation, we tried the … More living anionic polymerization of three beta-lactams, 3, 3-dimethyl-, 4, 4-dimethyl-, and 3-methyl-2-azetidinones (1, 2, and 3, respectively) to give monodisperse polyamides. Their polymerization using the corresponding N-benzoyl lactams and potassium pyrrolidonate as activators and a catalyst, respectively, in the mixture of N, N-dimethylacetamide (DMAc) with lithiium chloride (LiCl) proceeded in a homogeneous phase at 25ﾟC.The polyamides obtained from 1 and 2 were found to have a narrow molecular weight distribution (M_W/M_n<1.1) from GPC measurement using DMAc containing LiCl as an eluent. On the other hand, the value of M_W/M_n for the polyamide prepared from 3 was 1.2-1.3, although no termination was observed during the polymerization. From the results of the kinetic analysis of the aminolysis of the corresponding acyllactams, the broadening was speculated to be caused mainly by a low value of the ratio of the initiation reaction constant to the propagation one in the anionic polymerization of 3. Less