Development of chiral stationary phases consisting of low-molecular-weight cellulose derivatives covalently bonded to silica gel
Development of chiral stationary phases consisting of low-molecular-weight cellulose derivatives covalently bonded to silica gel
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DOI：
10.1023/a:1021188610098
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发表时间：
2002-01-01
期刊：
影响因子：
5.7
通讯作者：
Ohnishi, A
中科院分区：
文献类型：
--
作者：
Kasuya, N;Kusaka, Y;Ohnishi, A
我们制备了手性载体，其手性固定相（CSP）由低分子量纤维素衍生物（聚合度：15）组成，与硅胶共价键合。在偶联反应之前，用磷酸预水解用作CSP的基础材料的纤维素，以使纤维素中的还原末端与硅烷化二氧化硅表面上的氨基丙基结合。在用3，5-二氯苯基异氰酸酯或苯基异氰酸酯取代纤维素中的羟基后，我们测试了由此获得的CSP的手性识别性能，发现其具有广泛的手性识别能力。我们还证实了可以实现使用“强”溶剂作为移动的相的洗脱，这对于包被型CSP是困难的，因为移动的相可能溶解CSP.然而，当在包被型CSP上洗脱时，更多的对映体混合物显示出比在共价键合的CSP上更大的选择性因子（α）。作为对照CSP样品制备的由低分子量纤维素苯基氨基甲酸酯组成的涂层型CSP显示出与商业涂层型柱相当的性能（CHIRALCEL（R）OC），因此，化学键合的CSP的性能稍差可以通过由CSP组成的聚合物由于固定到硅胶。低聚合度可具有额外的效果。
We prepared chiral supports whose chiral stationary phase (CSP), consisting of a low- molecular- weight cellulose derivative (degree of polymerization: 15), is covalently bonded to silica gel. The cellulose used as the base material of the CSP was pre- hydrolysed with phosphoric acid before the coupling reaction to unite a reducing terminal in the cellulose and an aminopropyl group on the surface of silanized silica. After substituting hydroxyl groups in cellulose by using 3,5- dichlorophenyl isocyanate or phenyl isocyanate, we tested the CSP thus obtained for its performance in chiral recognition and found a wide range of chiral discrimination ability. We also confirmed that an elution using `strong' solvents as a mobile phase could be achieved, which is difficult for the coated- type CSPs because the mobile phase may dissolve the CSP. However, more enantiomeric mixtures showed larger selectivity factors ( alpha) when eluted on the coated- type CSPs than on the covalently bonded CSPs. A coated-type CSP consisting of the low- molecular- weight cellulose phenylcarbamate, prepared as a control CSP sample, showed comparable performance with the commercial coated- type column (CHIRALCEL(R) OC), so the slightly poorer performance of the chemically bonded CSPs may be explained by the difficulty of the polymer consisting of the CSPs in taking an optimal supermolecular structure required for chiral recognition due to the fixation to the silica gel. The low degree of polymerization may have an additional effect.