亲和膜手性拆分技术及手性拆分固膜

阐述了亲和膜拆分技术,包括亲和超滤、纳滤、电渗析、渗析及渗透汽化等在手性拆分领域的应用,对基于对映体间亲和性差异的手性选择膜及基于"形状记忆"的分子印迹拆分膜的最新进展进行了综述,并就今后的发展方向提出建议。     

氨基酸对映体的手性拆分

氨基酸对映体的分离是生命科学的基础,主要方法有高效毛细管电泳法、高效液相色谱法、薄层色谱法和气相色谱法等,高效液相色谱法是广泛应用的手性氨基酸拆分方法。本文介绍了间接法和直接法手性拆分的分离机理,并详细介绍了Pirkle手性固定相、胶束手性固定相、包合手性固定相、配体交换手性固定相、蛋白质手性 j固定相等5类手性固定相的应用。     

手性拆分液膜及固膜的研究进展

对外消旋体的手性拆分是获得单-对映体的有效途径,在诸多拆分方法中,膜拆分法以其能耗低、易连续操作,易工业放大的优点受到广泛关注,被认为是最有前途的方法.本文将膜技术分为液膜和固膜两部分,分别介绍了两者在手性物质拆分中的研究进展,并总结了各种方法的优缺点,在此基础上提出了存在的问题和今后的研究方向.     

手性拆分——化学拆分法的研究进展

综述了近年来化学拆分法的研究进展,重点分析了经典成盐拆分法、包结拆分法和组合拆分法三种拆分方法的研究进展以及各个拆分方法的优缺点。并对化学拆分法进行了总结和展望,在未来,随着高端化学品高纯度生产的需求,对于手性化合物的光学纯度要求也越来越高,化学拆分法由于操作简单、成本低、易于大规模生产等优势而广泛应用于对映异构体的拆分,在手性拆分领域将发挥重要、不可替代的作用。     

手性药物拆分新方法研究进展

手性是一种很普遍的自然现象,对生命体新陈代谢有着深远的影响.此外,手性还在医药、食品添加剂、杀虫剂、昆虫性信息索、香料和材料等领域有着深刻影响.特别是在医药行业,彼人体吸收的2个对映体在体内的作用不同,一般情况下其中一个单体有治疗作用,另一个具有毒性或者对病情无效.随着医药行业对手性单体需求量的增加和对药理的探究,如何...     

手性扁桃酸光学拆分研究进展

介绍了手性扁桃酸的各种拆分方法,讨论了各种方法的优缺点。以手性苯甘氨酸丁酯为拆分剂的方法操作简单、收率较高,适于工业化生产。     

超滤膜拆分手性化合物的研究进展

通过对手性化合物和超滤膜的介绍,综述了超滤膜在手性化合物拆分中的研究进展,并展望了超滤膜在膜拆分技术中的地位及其工业化发展前景。     

手性拆分膜的研究与应用新进展

手性拆分膜技术作为一种低能耗和易于工业放大的手性拆分技术,近年来随着单一手性物质需求的日益增长得到了广泛的关注。着重介绍了用于对映体分离的支撑液膜、乳化液膜、厚体液膜、扩散选择型手性固膜和吸附选择型手性固膜等膜分离技术的近期研究成果和应用开发现状,并总结了各种方法的优缺点。手性拆分液膜传输速度快,但稳定性较差;而稳定性好的手性拆分固膜,迄今尚难同时实现高选择性和高通量。因此,进一步研制一种既具有良好稳定性、又具有高精度和大通量的手性拆分膜具有重要的意义。     

手性化合物拆分方法的研究进展

光学活性物质的合成对生命科学具有重大意义。已在医药和农药工业中占有越来越重要的地位。本文介绍了几种主要的外消旋化合物的拆分方法。     

膜分离环烷酸工艺研究

研究利用无机陶瓷膜分离精制环烷酸的工艺。考察了操作方式、膜孔径、温度及压力等条件对工艺的影响。     

氨基酸的提取与精制

综合介绍了氨基酸提取过程中常用的分离技术以及近期的发展动态。如沉淀法、离子交换法、膜分离法和萃取法。并提出了氨基酸提纯精制的关键环节—结晶过程中应该注意的问题。     

Synthesis of Chiral Amino Acid Anilides by Ligand‐Free Copper‐Catalyzed Selective N‐Arylation of Amino Acid Amides

An atom‐economic, practical and cost‐effective protocol for synthesis of chiral amino acid anilides via ligand‐free copper‐catalyzed selective C N cross coupling of chiral amino acid amides and aryl halides, hetereoaryl halides and a vinyl bromide has been developed. No racemization occurred during the C N coupling. A plausible mechanism is proposed.     

膜分离技术制备高纯单宁酸的研究

工业单宁酸经改性活性炭预处理后,用超滤和纳滤技术纯化的方法制备高纯度单宁酸。重点考察了料液质量分数、操作压力差、料液温度对膜分离效果的影响。确定的最佳工艺条件是:料液质量分数 15%、截留相对分子质量为 6000 的超滤膜和截留相对分子质量为600的纳滤膜的操作压力差分别为 0.10 MPa 和 0.08 MPa、料液温度 40℃。同时探讨了颗粒活性炭通过硝酸氧化改性增强其吸附性能的方法。分析结果表明,膜分离技术有效地实现了不同分子质量的物料分级和截留,精品单宁酸的含量为 97.3%,收率为 84.7%。     

膜分离氨基酸的模型研究

以稳态条件下膜两侧氨基酸电离反应平衡和溶液电荷守恒为理论基础,推导了氨基酸总截留率与氨基酸分子（两性离子）截留率、氢离子截留率和溶质电离度之间的关系式以及氨基酸溶液中各种离子截留率的表达式,建立了一个膜分离氨基酸的唯象模型。利用该模型进行模拟计算,计算曲线与实验曲线基本吻合,所建立的模型为膜分离多元有机酸的截留规律研究提供了理论参考。     

Extraction of Amino-J Acid from Waste-water by Emulsion Liquid Membrane

The emulsion liquid membrane technique was used to extract amino-J acid from industrial dye waste-water. The effects of stirring speed, ratio of the emulsion to water (Rew), ratio of the oil to internal phase (Roi) and membrane phase components on the extraction rate were investigated and optimized. The results showed that the extraction rate of amino-J acid approached 97% when the stirring speed was 300 r/min, Rew 1:6, Roi 1:1, trioctylamine (TOA) 3 mL/100 mL kerosene, and methyl-didecyle-alcohol-acrylate (LMA-2) 3 g/100 mL kerosene, respectively. The extraction rate had not changed with the oil phase reused for times.     

Enantioseparation via EIC‐OSN: Process design and improvement of enantiomers resolvability and separation performance

This article presents a mathematical model to assess and optimize the separation performance of an enantioselective inclusion complexation‐organic solvent nanofiltration process. Enantiomer solubilities, feed concentrations, solvent compositions, permeate solvent volumes, and numbers of nanofiltrations were identified as key factors for process efficiency. The model was first tested by comparing calculated and experimental results for a nonoptimized process, and then, calculations were carried out to select the best operating conditions. An important finding was that the optimal configuration varied with the objective function selected, e.g., resolvability versus yield, with a boundary on product optical purity. The model also suggested that the process efficiency could benefit from diafiltration of the distomer and from the use of higher feed concentrations. However, the latter strategy would result in higher losses of eutomer. To address this drawback, a multistage process was evaluated using the verified process model. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

CO2 Capture Using Activated Amino Acid Salt Solutions in a Membrane Contactor

An activated solution based on amino acid salt was proposed as a CO₂ absorbent. Piperazine (PZ) was selected as an activating agent and added into the aqueous glycine salt to form the activated solution. A coupling process, which associated the activated solution with a PP hollow fiber membrane contactor, was set up. An experimental and theoretical analysis for CO₂ capture was performed. The performances of CO₂ capture by the coupling process were evaluated using the PZ activated solution and the non-activated glycine salt solution. A numerical model for the simulation of the hollow fiber membrane gas–liquid mass transfer was developed. Typical parameters such as outlet gas phase CO₂ concentration, capture efficiency, and mass transfer coefficient for the activated solution were determined experimentally. The effects of operation temperature and liquid CO₂-loading on mass transfer coefficient and capture efficiency were discussed in this work. Axial and radial concentration profiles of CO₂ in the fiber lumen and mass transfer flux were simulated by the model. Results show that the performances of the PZ activated glycine salt solution are evidently better than that of the non-activated glycine salt solution in the membrane contactor for CO₂ capture. Elevation of the operation temperatures can enhance the overall mass transfer coefficient. The activated solution can maintain higher capture efficiency especially in the case of high CO₂-loadings. The gas phase CO₂ concentration with the activated solution is lower than that with the non-activated solution whether along axial or radial distances in the fiber lumen. The model simulation is validated with experimental data.     

Optical Resolution of Racemic Mixtures of Amino Acids through Nanofiltration Membrane Process

Optical resolution of racemic mixtures of arginine and alanine was performed by chiral selective nanofiltration membrane. The chiral selective layer of the membrane was prepared by interfacial polymerization of metaphenylenediamine, trimesoyl chloride, and S (-)-2-acetoxypropionyl chloride (S-2-actoxpcl) in situ on the top of polysulfone ultrafiltration membrane. S-2-actoxpcl consists of a chiral carbon atom that has an induced chiral environment in the membrane. The membranes were characterized by FTIR, scanning electron microscopy, and atomic force microscopy to establish a structure-performance relationship. The optical resolution was performed on the membrane testing module and the effect of process parameters was determined. The results indicated that the incorporation of S-2-actoxpcl made membrane chiral selective hence membranes performed optical resolution. The resolution capacity increased by increasing S-2-actoxpcl in polymerizing solution up to 0.03% but any increase beyond 0.03% reduces the resolution capacity. More than 92% enantiomeric excess of D enantiomer was observed in the permeate of the membrane which was prepared from 0.07% trimesoyl chloride and 0.03% S-2-actoxpcl. The membrane prepared without the chain terminator exhibited less volumetric flux but more solute rejection compared to those prepared with the chain terminator. The flux of the membrane increases as the amount of the chain terminator in the reaction increases.     

用分子结构特征分析法研究氨基酸甜味产生原因

采用全略微分重叠法（ＣＮＤＯ法）对１３种呈味氨基酸的分子结构特征进行了计算，并对其与甜味间的关系进行了相关分析，结果表明：氨基酸α－Ｈ、羰基－Ｏ以及氨基上的一个氢原子与甜度极显著相关（Ｐ〈０．０１）。氨基酸可能以氢供给基（α－Ｈ）和氢接受基（羰基－Ｏ），与甜味接受体上的氢接受基（Ｂ）、氢供给基（ＡＨ）结合形成氢键；氨基上的一个氢原子与甜味接受体上第三点结合形成氢键，其强度决定甜味的强弱。