Synthesis of Ion-Exchange Membrane Containing Poly(carboxylic acid)-Supported Crown Ethers and Selective Transport of Metal Ions through the Membranes.

为了实现金属离子的选择性传输，将聚丙烯酰氧基苹果酸酐（AMA）、聚衣康酸酐（IA）、IA与丙烯腈的共聚物（IA-AN）与单氮杂冠醚反应，再与聚丙烯腈（PAN）按1：9 ~ 3：7的重量比共混，制备了聚羧酸支载单氮杂冠醚离子交换膜。已经进行了碱金属离子通过具有合适的共混物组成的膜从碱侧到酸侧的主动传输，以得到高的最大传输比和中等的传输速率。结果表明，疏水性的酸侧和亲水性的碱侧的膜适当地保持到运输系统。选择性通过两种碱金属离子的竞争性转运速率的比率来评价。AMA对照膜的<K^+> / <Na ^+>和<Na^+> / <Li^+>选择性分别为1.2和1.4，IA对照膜的选择性分别为1.6和1.4。对于（AMA）负载的单氮杂冠醚膜，<K^+> /<Na ^+>和<Na^+> / <Li^+>选择性增加到1.6 - 1.7和1.5 - 2.2，而对于（IA）负载的单氮杂冠醚膜，它们在1.0 - 1.8和1.3 - 1.8的范围内。N-羟乙基单氮杂冠醚对（AMA）选择性的取代基效应与单氮杂冠醚相似。酸性侧至中性缓冲液侧的转运系统发生变化，结果表明，（AMA）和（IA-AN）负载的N-羟乙基单氮杂冠醚膜的<K^+> / <Na^+>选择性在1.0 - 1.3之间，表明碱金属离子在含聚（AMA）和（IA-AN）负载的N-羟乙基单氮杂冠醚膜中的选择性较好（羧酸）负载的单氮杂冠醚没有通过含有单氮杂冠醚载体的液膜那么高。这种差异的原因可以用冠醚化合物的两种相反的作用来解释。

For the purpose of conducting selective transport of metal ions, ion-exchange membranes containing poly(carboxylic acid)-supported monoazacrown ethers were prepared by reactions of poly(acryloyloxymalic anhydride)(AMA), poly(itaconic anhydride)(IA), and copolymers of IA and acrylonitrile (IA-AN) with monoazacrown ethers, followed by blending with PAN by weight ratio of 1:9 - 3:7. Active transport of alkali metal ions from alkali side to acid side through the membrane having a suitable blend composition has been conducted to give high maximum transport ratio with moderate transport rate. The results suggest that a hydrophobic acid side and a hydrophilic alkali side of the membrane was suitably maintained to the transport system. Selectivity was evaluated by the ratio of competitive transport rates of two alkali metal ions. <K^+> / <Na^+> and <Na^+> / <Li^+> selectivities were 1.2 and 1.4 for (AMA) control membrane and 1.6 and 1.4 for (IA) control membrane, respectively. While <K^+> / <Na^+> and <Na^+> / <Li^+> selectivities increased to 1.6 - 1.7 and 1.5 - 2.2 for the membranes of (AMA)-supported monoazacrown ethers, they were in the range of 1.0 - 1.8 and 1.3 - 1.8 for the membranes of (IA)-supported monoazacrown ethers. Substituent effect of N-hydroxyethylmonoazacrown ether on the selectivity was almost similar to that of monoazacrown ether for (AMA). A change in the transport system of acid side to neutral buffer side, <K^+> / <Na^+> selectivity was in the range of 1.0 - 1.3 for the membranes of (AMA)- and (IA-AN)-supported N-hydroxyethylmonoazacrown ether.It is concluded that the selectivity of alkali metal ions in the active transport through the membranes containing poly(carboxylic acid)-supported monoazacrown ethers was not so high as through liquid membrane containing a carrier of monoazacrown ether. The reason for this difference may explain in terms of two opposite effects of crown ether compound.