以胺基聚合物为萃取介质分离生育酚同系物

发布时间：2018-04-15 22:29

本文选题：生育酚同系混合物 + 聚合物萃取剂　；参考：《浙江大学》2015年硕士论文

【摘要】：天然产物中的同系物因具有高度相似的结构和性质,其分离极具挑战。生育酚作为最有代表性的天然产物之一,含有α-、β-、γ-和6-生育酚四种同系物,它们的生物活性为δ-γ-β-α-生育酚,因此,从生育酚的同系混合物中分离α-生育酚具有重要的经济价值。鉴于现有生育酚同系混合物萃取分离溶剂体系的低分离效率和选择性,考虑到其同系物酸性的差异,我们首次提出以含有胺基的聚合物为萃取介质,用于生育酚同系混合物的萃取分离。为此,我们制备了三种不同分子量的甲基丙烯酸二甲氨基乙酯的均聚物(PDMAEMA),与乙腈(ACN)组成萃取剂体系,与用纯ACN作为萃取剂相比,生育酚在PDMAEMA萃取剂体系中的分配系数和选择性系数都明显提高。PDMAEMA30-ACN(ω(PDMAEMA)=38.9%)为萃取剂时,6-生育酚的分配系数是ACN作萃取剂时的4.4倍,6-对a-生育酚的选择性系数是ACN作萃取剂时的1.6倍。我们进一步以支化聚乙烯亚胺(PEI)为萃取介质,分别考察了助溶剂的种类、PEI分子量和浓度对萃取的影响。当以PEI-ACN为萃取剂体系时,生育酚表现出良好的分配和选择性。PEI上胺基与ACN的摩尔比为0.485时,δ-生育酚的分配系数为7.05,相应δ-对α-生育酚的选择性系数为5.92。同时,研究发现PEI对C02刺激有很好的响应能力,可用于萃取相中生育酚的快速回收：萃取相中通CO2,仅需正己烷3次反萃就可回收生育酚超过90%；而不使用COz,理论上需要正己烷反萃12次,生育酚的回收率才能达到90%。经回收生育酚后的PEI萃取相通过加热和通N2,可释放出CO2重新作为萃取剂使用,经循环使用3次测试,生育酚的分配系数仅下降约10%,选择性系数几乎不变。由于PEI对生育酚具有良好的萃取选择性,我们进一步以二氧化硅负载的PEI为吸附剂,研究了采用吸附法从生育酚同系混合物中分离α-生育酚,同样获得了很高的生育酚吸附率和分离因子。吸附剂的质量与生育酚同系混合物溶液的体积之比为0.4g/mL时,δ-生育酚的吸附率为96.1%,δ-和α-生育酚的分离因子可达12.1。吸附生育酚后的二氧化硅负载的PEI可在ACN或者乙醇中高效脱附。
[Abstract]:The separation of homologues in natural products is challenging due to their highly similar structures and properties.As one of the most representative natural products, tocopherol contains four homologues of 伪 -, 尾 -, 纬-and 6-tocopherol. Their biological activity is 未-纬-尾-伪 -tocopherol. Therefore, the separation of 伪 -tocopherol from tocopherol mixture has important economic value.In view of the low separation efficiency and selectivity of the existing extraction and separation solvent systems for tocopherol mixtures and considering the difference in the acidity of their homologues, we proposed for the first time that polymers containing amino groups should be used as the extraction medium.It is used for extraction and separation of tocopherol homologous mixture.For this reason, we have prepared three kinds of homopolymer of dimethylaminoethyl methacrylate with different molecular weight, PDMAEMAN and acetonitrile (acetonitrile) as extractant system, compared with pure ACN as extractant.The partition coefficient and selectivity coefficient of tocopherol in PDMAEMA extractant system were obviously increased. The partition coefficient of tocopherol was 4.4 times as high as that of ACN as extractant, and the selectivity coefficient to a- tocopherol was 1.6 times higher than that of ACN as extractant.We further investigated the effects of molecular weight and concentration of PEI on the extraction with branched polyethyleneimide (PEI) as the extraction medium.When PEI-ACN was used as extractant, tocopherol showed good distribution and selectivity. The molar ratio of amino group to ACN was 0.485, the partition coefficient of 未 -tocopherol was 7.05, and the selectivity coefficient of 未-to 伪 -tocopherol was 5.92.At the same time, the study found that PEI has a good response to CO2 stimulation,It can be used for quick recovery of tocopherol in extraction phase. In extraction phase, the recovery rate of tocopherol can be more than 90 by only 3 times stripping of n-hexane, but without using COz. in theory it needs 12 times of n-hexane to recover tocopherol, and the recovery rate of tocopherol can reach 90%.After the recovery of tocopherol, the PEI extraction phase can release CO2 to be used as extractant by heating and passing through N _ 2. The distribution coefficient of tocopherol is only decreased by about 10% and the selectivity coefficient is almost unchanged after three times of recycling test.Because PEI has good selectivity for extraction of tocopherol, we further studied the separation of 伪 -tocopherol from tocopherol homologous mixture by using silica supported PEI as adsorbent.The high adsorption rate and separation factor of tocopherol were also obtained.When the mass ratio of adsorbent to the volume of tocopherol homologous solution is 0.4g/mL, the adsorption rate of 未 -tocopherol is 96.1, and the separation factor of 未-and 伪 -tocopherol is 12.1.PEI supported on silica after adsorption of tocopherol can be desorbed efficiently in ACN or ethanol.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ028;TQ28

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