共查询到20条相似文献,搜索用时 62 毫秒
1.
总结了近期提取和分离纯化方法在天然植物中生物碱类有效成分研究中的应用,特别是对于吸附树脂法在生物碱纯化中的应用进行了系统综述,归纳了具有不同结构的大孔吸附树脂、凝胶型离子交换树脂和大孔型离子交换树脂对生物碱纯化效果的影响规律,进而为高效、高选择性纯化生物碱的专用吸附树脂结构设计和应用提供了可借鉴的研究思路. 相似文献
2.
基于高交联聚苯乙烯树脂骨架上悬挂双键的二次引发,设计合成了一类弱极性酯基功能基含量较高且兼具高比表面积的新型大孔吸附树脂,在吸附分离中表现出偶极-疏水协同作用机制,用于甜菊糖中结构相近的单体糖苷Rebaudioside D (简称RD)的分离纯化,克服了传统吸附树脂的选择性和吸附容量不能兼顾的缺点,对甜菊糖粗提物纯化后,RD苷的纯度由7.1%提高到51.2%。 相似文献
3.
研究了含吡啶功能基大孔吸附树脂对甜菊糖的吸附量与吸附选择性作用 .分析了树脂极性及不同骨架结构对吸附选择性的影响 .并分别通过甲醇或乙醇的选择性洗脱及树脂动态吸附分离两种方法研究树脂对甜菊糖中莱鲍迪甙A的富集作用 .结果表明 ,树脂动态分离法可以有效地从高甜菊甙甜菊糖中分离富集出高莱鲍迪甙A产品 ,该方法具有一定的工业应用前景 . 相似文献
4.
该项研究发现了大孔交联聚苯乙烯型离子交换树脂的合成方法,研究了惰性溶剂的性质与树脂的孔结构、树脂的孔结构与树脂的性能、树脂的特性与用途等方面的关系。在此基础上,研制出高强度、抗辐射、动力学性能优越的大孔型离子交换树脂,使其不仅能更好地应用于无机离子的交换,还开拓了在有机合成、制药等领域的催化、脱色、提纯等多方面的广泛应用。在多孔性离子交换树脂的基础上,还研制出系列吸附树脂。此类提取、分离材料,可以有不同的结构和不同的吸附性能,在天然产物的提取分离、抗菌素的提取、纯化、医疗、环境保护等领域有实际用途。上述两类功能高分子材料在多家企业实现了产业化,为化工、制药、环保、医疗、分析等诸多行业提供了必要的材料,在国民经济的发展中发挥了重要作用。 相似文献
5.
针对黄酮分子的酚羟基结构特点,有目的地选择了4种结构不同的商品化树脂,考察了它们对沙棘叶中黄酮类有效成分的吸附能力和吸附选择性.在此基础上优化了树脂结构设计方案,合成了具有氨基功能基、可形成氢键作用、疏水性可调变的大孔吸附树脂.以沙棘叶粗提物为原料,考察了树脂骨架疏水性、功能基间隔臂长短等对树脂纯化效果的影响规律.研究结果表明,当吸附发生在水体系中,一定强度的疏水性作用是树脂与吸附质之间形成氢键的必要条件,对于尺寸较大的黄酮分子,氢键功能基的间隔臂长短也显著影响了树脂对它的吸附能力.最后,我们选择了疏水性和氢键功能基间隔臂长短适宜的XM20-2树脂,对吸附和洗脱条件进行了优化,将其用于沙棘叶粗提物中黄酮类有效成分的进一步纯化,可将黄酮纯度从粗提物中的10.4%提高到50%以上,且树脂具有很好的重复使用性. 相似文献
6.
大孔吸附树脂(macroprous adsorption resin, MAR)是近几十年发展起来的一种具有多孔立体结构、人工合成的有机高分子聚合物。由于其特殊的理化性质和吸附性能,已被广泛应用于化学、医药、环保和食品等领域。本文介绍了近年来国内外对大孔吸附树脂在吸附机理研究方面的进展,重点介绍了不同温度条件下大孔吸附树脂对靶标分子的吸附热力学行为模式,靶标分子在大孔吸附树脂表面及孔内的吸附扩散行为模式。此外,大孔吸附树脂性能参数和靶标分子结构参数之间构效关系也对其吸附选择性规律具有重要的影响。因此,大孔吸附树脂与底物间构效关系的匹配程度及其对选择性的影响是大孔吸附树脂分离理论研究的核心。本文最后介绍了可以准确客观描述吸附过程并具有一定使用范围的大孔吸附树脂吸附模型的建立和评价。 相似文献
7.
以具有高比表面积的后交联大孔共聚物为基础,进一步和三甲胺、二甲胺、α-甲基吡啶等有机胺类进行胺化反应,引入功能基,从而制得一类带有离子交换功能的大孔吸附树脂.其物理和化学结构测定证实这类树脂既具有高比表面,又带有一定数量的交换基团.并研究了它们对苯酚和Au(l)的吸附一脱附性能. 相似文献
8.
超高交联吸附树脂对多种芳香有机化合物较高的吸附容量主要源于其密集的微孔和双峰孔分布.对大孔吸附树脂及超高交联吸附树脂采用不同极性功能基团进行化学修饰可以制得系列离子交换与吸附双重功能吸附树脂,该类树脂对亲水性有机污染物同时具有疏水、静电、络合等多重作用.丙烯酸酯类吸附树脂在吸附芳香磺酸盐时,树脂的骨架和功能基团对吸附过程都有重要的贡献. 相似文献
9.
设计并合成了一系列疏水性 (包括非极性和不同极性 )和亲水性大孔吸附树脂 ,研究它们对甜叶菊糖甙的吸附性能与吸附机理 .紫外光谱与HPLC研究表明 ,吸附剂的骨架结构和极性对总甙吸附量及其对甜菊甙和莱鲍迪甙A的吸附选择性有显著影响 .并利用树脂对不同极性糖甙吸附的弱选择性作用成功地分离出莱鲍迪甙A产品 . 相似文献
10.
本文报告了用非极性大孔吸附树脂法从复方中药中提取分离有效成分的研究。结果表明,正确地选择大孔吸附树脂及吸附和解吸条件,可得到高纯度的有效组分,其粘度低,有利于制剂。 相似文献
11.
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
13.
由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
14.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献
15.
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
16.
The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness. 相似文献
17.
实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。 相似文献
18.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins of Abies alba M., Larix decidua M., and Picea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins of Abies alba, Picea excelsa, and Picea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while in Larix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
20.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
|