醇/盐双水相体系中手性物质识别及包结作用的研究

【作者】 郭志峰；

【导师】 李芬芳；

【作者基本信息】 中南大学 ， 有机化学， 2011， 硕士

【摘要】 本文采用一种全新、环保、易于操作的生物提取分离技术——含手性识别剂的醇/盐双水相体系对扁桃酸(MA)、α-环己基扁桃酸(CHMA)对映体进行了手性识别研究。主要内容如下：首先,对环糊精类手性识别剂在醇/盐体系中手性识别能力进行了筛选研究。分别考查了环糊精类手性识别剂β-环糊精(β-CD)、羟丙基-β-环糊精(HP-β-CD)、羟丙基-α-环糊精(HP-α-CD)、磺化-β-环糊精(S-β-CD)、水溶性-β-环糊精聚合物(β-CDP)在乙醇/硫酸铵、乙醇/磷酸氢二钾、异丙醇/硫酸铵、异丙醇/磷酸氢二钾、正丙醇/硫酸铵、正丙醇/磷酸氢二钾体系中的手性识别效果。研究结果显示：在考察的几种环糊精类手性识别剂中只有β-CD,HP-β-CD对CHMA对映体有比较强的手性识别能力、S-β-CD对MA对映体有一定的手性识别能力。β-CD和HP-β-CD只有在乙醇/硫酸铵体系中对CHMA对映体才有比较强的手性识别能力,S-β-CD也只有在乙醇/硫酸铵体系中才对MA对映体表现出明显的手性识别能力。其次,考查了羟丙基-β-环糊精在乙醇/硫酸铵双水相体系中对α-环己基扁桃酸对映体的手性识别影响因素。分别考查了HP-p-CD浓度、CHMA浓度、乙醇和硫酸铵质量分数、体系温度和pH值等因素对CHMA对映体分配比(D)和分离因子(α)的影响。结果显示：体系中HP-β-CD浓度、乙醇质量分数、温度和pH值等因素对对映体的分离度影响较大；在体系温度为40℃,pH值为2,乙醇质量分数为30%,硫酸铵质量分数为15%,HP-β-CD的浓度为50g.L-1,CHMA浓度为0.5mmol.L-1时,手性识别分离效果最佳,一次萃取分离后,R和S对映体的分配比(DR和DS)分别为1.08和0.61,分离因子(α)达到了1.86。第三,研究了磺化-β-环糊精在乙醇/硫酸铵双水相体系中对扁桃酸对映体的手性识别影响因素。分别研究了S-β-CD的取代度、S-β-CD的浓度、醇和盐的浓度、温度、pH值等因素对手性识别效果的影响。结果显示,在含有手性识别剂S-β-CD(Ⅱ)的乙醇/硫酸铵双水相体系中,MA对映体的最大分离因子α可达到1.65,上相中对映体过量值e.e%可达到15.7%。第四,研究了β-环糊精双核铜络合物(Cu2-β-CD)在醇/盐体系中手性识别能力。首先在水溶液中制备了β-环糊精双核铜络合物,并采用红外、紫外光谱和X射线衍射对其进行了表征。将Cu2-β-CD作为手性识别剂添加到醇/盐双水相体系中,详细考察了Cu2-β-CD在乙醇/硫酸铵、乙醇/磷酸氢二钾、异丙醇/硫酸铵、异丙醇/磷酸氢二钾、正丙醇/硫酸铵、正丙醇/磷酸氢二钾六种醇/盐双水相体系中对CHMA对映体的手性识别能力。研究结果显示：Cu2-β-CD配合物在乙醇/硫酸铵体系和异丙醇/硫酸铵体系中对CHMA对映体表现出一定的手性识别能力,而在其它四种醇/盐体系中对CHMA对映体皆没有表现出明显的手性识别能力。然后选取乙醇/硫酸铵体系作为实验体系,详细考察了Cu2-β-CD的浓度、乙醇和硫酸铵质量分数、温度、pH值等因素对手性识别效果的影响。结果表明,在Cu2-β-CD配合物浓度为20 mmol.L-1,体系乙醇含量为35%,硫酸铵含量为15%,体系温度为30℃,pH值为6时,分离因子α达到最大值1.47。第五,利用红外光谱法分别研究了羟丙基-β-环糊精对α-环己基扁桃酸、磺化-β-环糊精对扁桃酸、β-环糊精双核铜络合物对α-环己基扁桃酸的包结作用。结果表明：HP-P-CD与CHMA形成包结物后改变了原有主一客体化合物固有的红外吸收峰的位置和形状,C=O伸缩振动吸收峰从1728cm-1处移动到1715cm-1处,而且峰形变宽；S-β-CD与MA形成包结物后,使得C=O伸缩振动吸收峰1716cm-1处微移到1720cm-1处,而且峰形变宽；Cu2-β-CD与CHMA形成包结物后,使得C=O伸缩振动吸收峰完全消失。上述红外光谱实验皆证实了HP-β-CD与CHMA、S-β-CD与MA、Cu2-β-CD与CHMA包结物的形成。更多还原

【Abstract】 In this paper, mandelic acid(MA) enantiomers andα-cyclohexyl-mandelic acid (CHMA) enantiomers were separated by a novel chiral separation extraction systems-Alcohol/salt-based aqueous two-phase systems(ATPSs). The main contents can be summarized as follows:The first,the screening study of chiral recognition ability for cyclodextrins group reagents in the alcohol/salt-based aqueous two-phase system:Chiral recognition of mandelic acid and a-cyclohexyl-mandelic acid by alcohol/salt-based aqueous two-phase systems(C2H5OH/(NH4)2SO4、C2H5OH/K2HPO4、n-C3H7OH/(NH4)2SO4、n-C3H7OH/K2HPO4、i-C3H7OH/(NH4)2SO4、i-C3H7OH/K2HPO4) containing chiral selector(P-cyclodextrin、hydroxypropyl-β-cyclodextrin、hydroxypropyl-a-cyclodextrin、sulfonated-β-cyclodextrin、water-soluble (3-cyclodextrin polymer). The experimental results indicate that only P-cyclodextrin and hydroxypropyl-β-cyclodextrin as chiral selector showed a good chiral recognition ability toward CHMA enantiomers. Sulfonated-β-cyclodextrin have a chiral recognition ability toward MA enantiomers. It was also found that β-cyclodextrin and hydroxypropyl-β-cyclodextrin only have a chiral recognition ability in the C2H5OH/(NH4)2SO4 system. Sulfonated-β-cyclodextrin also only have a chiral recognition ability in the C2H5OH/(NH4)2SO4 system.The second,the dependency of the distribution ratio (D) and the separation factors(α) on parameters, such as the concentration of HP-β-CD,the concentration of CHMA, the mass fractions of C2H5OH and (NH4)2SO4 respectively,temperature and pH have been investigated. It could be concluded that the enantioseparation strongly depended on the concentration of HP-β-CD,the mass fraction of C2H5OH,temperature and pH. The optimum conditions of enantioseparation were as follows:The temperature was 40℃,the pH was 2.0,the mass fraction of C2H5OH and (NH4)2SO4 was 30%and 15%, respectively,the concentration of HP-β-CD was 50 g.L-1 the concentration of CHMA was 0.5 mmol.L"1.Under these conditions the separation factor(a) reached at 1.86. The third,the dependency of the distribution ratio (D) and the separation factors(a) on parameters such as the concentration of S-β-CD,the concentration of CHMA, the mass fractions of C2H5OH and (NH4)2SO4respectively,temperature and pH have been investigated. The maximum enantioselectivity(a=1.65, e.eup=15.7%) was reached by employing S-P-CD(Ⅱ) as chiral selector in the ethanol/ammonium sulfate system.The forth,the study of chiral recognition ability for Cu2-β-CD in the alcohol/salt-based aqueous two-phase system:Firstly,The dinuclear Cu2-β-CD complex was synthesized and characterized by IR、UV、XRD. The chiral recognition system was established by adding Cu2-β-CD into the alcohol/salt-based aqueous two-phase system. The experimental results show that the C2H5OH/(NH4)2SO4 and i-C3H7OH/(NH4)2SO4 aqueous two phase extraction system containing Cu2-β-CD has well chiral recognition ability toward CHMA enantiomers.Then,the dependency of the distribution ratio (D) and the separation factors(a) on parameters such as the concentration of Cu2-β-CD, the mass fractions of C2H5OH and (NH4)2SO4 respectively,temperature and pH were investigated. The experimental results indicate that the optimum conditions of enantioseparation were as follows:The temperature, was 30℃,the pH was 6.0,the mass fraction of C2H5OH and (NH4)SO4 was 35% and 15%, respectively,the concentration of Cu2-β-CD was 20 mmol.L-1,the concentration of CHMA was 0.5mmol.L-1.Under these conditions the separation factor(a) reached at 1.47.The fifth,the inclusion behavior between HP-β-CD and CHMA、S-β-CD and MA、Cu2-p-CD and CHMA was studied by infrared spectroscopy.The results indicate that the characteristic peak of-C=O group of CHMA in its inclusion compound of HP-β-CD/CHMA shifted from 1728 cm-1 to 1715 cm-1,the characteristic peak of-C=O group of CHMA disappeared in the infrared spectra of the inclusion compound of Cu2-β-CD/CHMA, the characteristic peak of-C=O group of MA in its inclusion compound of S-β-CD-MA shifted from 1728cm-1 to 1715 cm-1.The infrared spectra indicate that HP-P-CD and CHMA, S-β-CD and MA、Cu2-β-CD and CHMA all form the inclusion compound.更多还原