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，这是一种具有N-甲基葡聚糖胺官能团的硼选择树脂。结合硼酸根在聚合物表面的分布测量，用核磁共振波谱研究了硼酸根与多元醇形成络合物的性质。研究结果如下：(1)研究了交联葡聚糖对硼酸盐的吸附作用。DELTAH值与单糖形成的硼酸盐络合物的DELTAH值相当，硼的浓度依赖于对硼的吸附是交联葡聚糖的一个特征。(2)观察到了固体凝胶和葡聚糖溶液的高分辨核磁共振波谱。在葡聚糖体系中，存在与α，β-二醇和α，γ-吡喃葡萄糖苷残基的硼酸盐络合物。这个Cro…葡聚糖交联度越高，交联聚合物配体中α，β-二醇部分的有效浓度越高，1：2络合反应随着交联度的增加而变得更易发生。(3)交联葡聚糖凝胶对硼的吸附具有浓度依赖性，这可能是由于硼酸盐与凝胶相中的固定阴离子位置之间的静电斥力而将硼酸盐阴离子排除在凝胶相之外。各络合物的稳定常数与Sephadex体系相似：QAE-Sephadex凝胶相中固定阳离子基团的存在对硼的吸附没有促进作用。(4)当平衡的本体溶液的pH值为6-11时，N-甲基葡萄糖胺树脂相的pH在10-11范围内保持恒定。在较宽的pH范围内，树脂对硼酸盐有很强的吸附能力，这就是该现象的原因。通过~&lt；11&gt；B的MAS-核磁共振测试，证实了树脂中的活性物种是功能团中的α，β-二醇的硼酸盐络合物。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，合成了一种新型的选择性硼聚合物。这种树脂的性能现在正在研究中。较少

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