Characterization, Synthesis, and Application of Borate-selective Polymers

研究使用市售的线性葡聚糖和交联多元醇，如Sephadex凝胶、QAE-Sephadex阴离子交换葡聚糖凝胶和Amberlite IRA-743（一种具有n-甲基氨基葡萄糖官能团的硼选择性树脂）。结合硼酸盐在交联聚合物上的分布测量，采用^< 11b> B核磁共振波谱法阐明了硼酸盐与多元醇络合物形成的性质。结果如下：(1)交联右旋糖酐对硼酸盐的吸附。DELTAH值与硼酸盐与单糖络合物形成的值相当，硼吸附对硼酸盐浓度的依赖是交联右旋糖酐的一个特征性质。(2)固体凝胶和右旋糖酐溶液的核磁共振光谱分辨率均< 11b>b。在葡聚糖体系中，硼酸盐配合物与α， β -二醇和α， γ -二醇的糖苷残基存在。右旋糖酐的增加导致交联聚合物配体中α、β -二醇基团的有效浓度高于实际浓度，从而随着交联程度的增加，更有利于1:1的络合。(3)交联葡聚糖凝胶吸附硼的硼酸盐浓度依赖性可能是由于凝胶相中硼酸盐与硼酸盐配合物的固定阴离子位之间的静电斥力使硼酸盐阴离子被排除在凝胶相中所致。各配合物的稳定常数与Sephadex体系的稳定常数相似：固定阳离子基在QAE-Sephadex凝胶相中的存在并没有促进硼的吸附。(4)当平衡体溶液pH为6 ~ 11时，n -甲基氨基葡萄糖树脂相的pH值在10 ~ 11范围内保持不变。硼酸盐在较宽的pH范围内对树脂的强吸附是由于这种现象。从^<11 b> B的MAS-NMR测量中，树脂中的活性物质被证明是官能团中α， β -二醇的硼酸盐配合物。在此基础上，通过在氯甲基化聚苯乙烯中引入三（羟甲基）基团合成了一种新型的硼选择性聚合物。目前正在研究这种树脂的性能。少

Studies were done using commercially available linear dextran and crosslinked polyols such as Sephadex gel, QAE-Sephadex anion-exchange dextran gel, and Amberlite IRA-743, a boron-selective resin which has a functional group of N-methylglucamine. Together with the distribution measurements of borate on the crosslinked polymers, ^<11>B NMR spectroscopy was employed to elucidate the nature of the complex formation of borate with the polyols. The results obtained were as follows : (1) for the adsorption of borate on a crosslinked dextran. DELTAH values were comparable to those for the complex formation ob borate with monosaccharides and the borate concentration dependence of boron adsorption is a characteristic property of the crosslinked dextran. (2) Well-resolved ^<11>B NMR spectra for the solid gel as well as for a dextran solution were observed. In the dextran system, borate complexes both with alpha, beta-diols and alpha, gamma-diols of glucopyranoside residues were present. This cro … More sslinking of dextran caused the effective concentration of alpha, beta-diol moieties in the crosslinked polymer ligand to become higher than the practical concentrarion, so that the 1 : 2 complexation became more fovorable accoding to the increase in the degree of crosslinking. (3) The borate concentration dependence of boron adsorption on crosslinked dextran gel may be caused by the exclusion of borate anions from the gel phase due to electrostatic repulsion between borate and the fixed anion sites of borate complexes in the gel phase. The stability constant of each complex is similar to that for the Sephadex system : the presence of the fixed cation group in the QAE-Sephadex gel phase did not promote the boron adsorption. (4) The pH of the N-methylglucamine resin phase remains constant in the range of 10 to 11 when the equilibrated bulk solution is pH 6-11. The strong adsorbability of borate on the resin in a wide pH range is due to this phenomenon. From the ^<11>B MAS-NMR measurements, the active species in the resin were proved to be borate complexes of alpha, beta-diols in the functional groups.On the basis of the results obtained, a novel boron-selective polymer was synthesized by introducing tris (hydroxymethyl) groups into chloromethylated polystirene. The properties of this resin are now being investigated. Less