Enantioselective extraction of mandelic acid enantiomers based on chiral ligand exchange

Based on the chiral ligand exchange, the distribution behavior of mandelic acid enantiomers, and the partition of Cu^2 at different pH values were studied in a water/alcohol two-phase system containing Cu^2 and N-ndodecyl-L-proline(A). The influences of the solvent sort, the pH value, the concentrations of Cu^2 and chiral ligand on the partition coefficient(K) and separation factor(α) were discussed. The experimental results show that the A formed has more stable ternary complex with D-mandelic acid enantiomer than with L-mandelic acid enantiomer. There is an important influence of the pH value on K and a. When the pH values are less than 3.5, the formation of binary complexes is thermodynamically unfavourable. K and a become maximum when pH values are above 3.5 and the molar ratio of the chiral ligand to Cu^2 is 2:1.     

Chiral extraction of ketoprofen enantiomers with chiral selector tartaric esters

Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-tartaric esters and methanol aqueous, kind of organic solvent on partition ratio and separation factors was investigated. The results show that L-tartaric and D-tartaric esters have different chiral recognition abilities. S-ketoprofen is easily extracted by L-tartaric esters, and R-ketoprofen is easily extracted by D-tartaric esters. L-tartaric esters form more stable diastereomeric complexes with S-enantiomer than that with R-enantiomer. This distribution behavior is consistent with chiral recognition mechanism. With the increase of the concentration of tartaric ester from 0 to 0.3 molL, partition coefficient K and separation factor α increase. Also, the kind of organic solvent and the concentration of the methanol aqueous have significant influence on K and α.     

超临界CO2萃取生物油脂成份的GC—MS分析

生物油脂经超临界CO2萃取提纯，再经甲酯化处理后，用气相色谱-质谱联用分离技术对其各组份进行定性分析．实验结果表明：该方法对样品分离效果良好．所测样品主要成分及含量分别为12-碳烯-十八酸42．70％、花生四烯酸14．92％、5-甲基-十七酸10．33％、8，11，14-二十碳三烯酸6．31％。     

盐析-萃取法处理精苯废酸的中试研究

在中试规模上采用盐析-萃取法处理精苯废酸。结果表明,当物料配比m（废酸）：m（母液）：m（粗酚）=1：0．3：0．4时,COD的脱除率最高达到95．3％,且萃取剂粗酚可以循环使用,不影响萃取效果;净化酸可再利用生产硫酸铵,其各项质量指标均不低于用新鲜硫酸生产的硫酸铵;萃取剂再生残渣（焦油渣）用于配煤炼焦可改善焦炭质量。     

利用酒石酸土柱淋洗法修复重金属污染土壤

通过室内模拟试验,采用土柱淋洗方法,研究酒石酸溶液两种不同添加方式对冶炼厂土壤中重金属离子去除率的影响,采用连续分级方法研究了淋洗前后冶炼厂土壤中重金属形态的变化.结果表明,2.5 L酒石酸5次加样的淋洗效果明显好于10次加样的淋洗效果,其中5次加样淋洗能去除91.3%的Cd,11.1%的Pb,39.2%的Zn,11.1%的Cu;淋洗过程中铅的穿透曲线明显滞后于镉、铜和锌3种重金属离子.形态分级结果表明,酒石酸5次加样淋洗能有效去除污染土壤中交换态和碳酸盐结合态部分重金属离子,明显降低氧化物结合态部分重金属离子,而对有机态和残余态部分重金属离子作用效果不明显.可见用酒石酸土柱淋洗法修复重金属污染的土壤是可行的.     

酸法提取斑点叉尾鮰鱼皮胶原工艺的条件优化

采用酸法从人工养殖的鮰鱼皮中提取胶原,并研究了酸的种类、酸的浓度、料液比、提取时间和提取温度对胶原提取率的影响.正交实验研究结果表明,最适提取工艺条件为：乙酸浓度1.0 mol/L,固液比1∶30,提取时间72 h,在5℃下提取得率为33.79%,提取胶原的最大紫外吸收波长为236 nm,和标准品紫外吸收波长基本一致.     

HPLC手性流动相添加剂法拆分巴氯芬对映体

建立了以羧甲基-β-环糊精为手性流动相添加剂,在反相液谱条件下拆分巴氯芬对映体的方法。研究了手性添加剂的种类及浓度、流动相组成、pH值及流速等尉崇对拆分的影响。流动千H为甲醇、乙腈、水,体积比为90：5：5,其中含2．00g／LCM-β-CD,pH值5．95,流速0．60mL／min,检测波长231nm,分离度为1．31。该方法简便、快速、相对偏差小。     

Preparation of long alumina fibers by sol-gel method using tartaric acid

Long alumina fibers were prepared by sol-gel method.The spinning sol was obtained by mixing aluminum nitrate,tartaric acid,and polyvinylpyrrolidone with a mass ratio of 10∶3∶1.5.Thermogravimetry-differential scanning calorimetry (TG-DSC),Fourier transform infrared (FT-IR) spectra,X-ray diffraction (XRD),and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibers.A little of α-Al2O3 phase is observed in the alumina precursor gel fibers sintered at 1273 K.The ...     

手性氨基酸拆分研究进展

氨基酸是组成蛋白质的基本单元,在人体及动物生命活动中起着举足轻重的作用.光学纯氨基酸是合成多肽和内酰胺类抗生素等药物的重要中间体,在药物合成、新材料合成、食品添加剂和精细化学品的开发等方面都具有巨大的应用价值.然而,人工合成的氨基酸大多是外消旋体.外消旋氨基酸的两个异构体在多数情况下具有不同的生理作用,有时甚至药性完全相反.对外消旋氨基酸进行拆分是获得手性氨基酸的重要方法.综述了近年来国内外氨基酸拆分的一些研究进展.     

金银花提取物中绿原酸的HPLC测定

建立了一种金银花提取物中绿原酸的高效液相色谱测定方法。具体方法为:采用Kromasil C18柱(250mm×4.6mm,5μm)、CH3CN-0.3%H3PO4的溶液(10∶90,V/V)作为流动相,检测波长为327nm,进样量20μL。结果表明绿原酸和金银花中其它成分能获得良好的分离,绿原酸在0.0256~0.0896 mg.mL内线性关系良好,平均回收率97.58%。该法简便、快速、准确,适于金银花提取物中绿原酸的测定。     

高位阻叔胺(N_(3418))自盐酸溶液中萃取钯的研究

以高位阻叔胺萃取剂Ｎ３４１８自盐酸溶液中对Ｐｄ（Ⅱ）进行了萃取研究．对萃取时间、水相的酸度、水相ｐＨ值、萃取剂的浓度、稀释剂等影响因素进行了较全面的分析；用硫脲作反萃剂对反萃率进行了探讨．应用连续变换法、饱和法、斜率法确定了配合物的组成为１∶４，并用红外光谱对萃合机理进行了初步讨论．     

Nickel extraction from low grade laterite by agitation leaching at atmospheric pressure

This research work deals with the extraction of nickel from a low grade nickel laterite ore, taken from a deposit located in southwestern of Iran, through agitation leaching at atmospheric pressure. The assaying and mineralogical studies carried out on the nickel laterite sample, showed the 0.88% Ni, and principally consisted of oxide and silicate crystalline phases i.e. dolomite, quartz, magnetite, and goethite. Among numerous factors affecting such process, four major parameters i.e. temperature, agitator speed (r/min), leaching agents and their concentration were considered in a two-level full factorial experimental design. The agitation leach tests showed that the ore could be leached at atmospheric pressure with sulfuric acid while citric acid was almost unpromising. Analysis of variance (ANOVA) using DX7 software was employed to identify effective parameters. Sulfuric acid concentration and temperature were the most effective parameters on Ni extraction. Furthermore, the factorial models for experiment responses were developed. The results showed 83% Ni extraction after 4 h leaching, under optimized conditions i.e. temperature at 95 °C, acid concentration at 5 N and agitator speed at 1000 r/min. This study revealed that factorial experimental design can be implemented to identify effective parameters on the agitation leaching process of nickel laterite.     

超声辅助乙醇提取龙葵生物总碱的研究

通过正交试验确定传统乙醇溶液提取龙葵生物总碱的最佳提取条件,在此基础上,研究超声辅助乙醇提取龙葵生物总碱的工艺条件,并对提取物龙葵生物总碱进行了定性、定量分析.实验表明:超声辅助乙醇提取龙葵生物总碱,提取率略高于传统提取技术,可节省提取时间和外加能源.     

The synergistic mechanism of solvent extraction of gold in HCI media with TOA and TOPO

The mechanism of synergistic extraction of gold in HCl media was researched with tri-n-octyl amine(TOA) and tri-n-octyl phospine oxide(TOPO). It was determined that the composition of synergistic extract is (TOAHTOPO) AuCl₄; the constant of synergistic extracting equilibrium is 10^9.20; and the synergistic reaction is exothermic with − 17.187 kJ/K· mol of ΔH ₂₉₈. The extraction mechanism was also studied by the IR-spectra and UV-spectra. It is found that the extraction mechanism belongs to ion-association type. Synopsis of the first author Yang Tianzu, professor, born in April 1958, majoring in the metallurgy of precious metals and coordination chemistry in hydrometallurgy.     

Organic acids and inorganic anions in Bayer liquors by ion chromatography after solid-phase extraction

A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS 11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.     

TMK小体积萃取法测定痕量金

介绍了TMK-TBP（硫代米蚩铜-膦酸三丁酯）小体积萃取法测定痕量金,该方法简便快速,所需设备简单,可用于实际样品中痕量金的测定,其最低检测限为1.5ng/ml.方法的精密度为5.24%。     

Extraction of vanadium from vanadium slag by high pressure oxidative acid leaching

To extract vanadium in an environment friendly manner, this study focuses on the process of leaching vanadium from vanadium slag by high pressure oxidative acid leaching. Characterizations of the raw s...     

固相萃取-分光光度法测定痕量苯酚

在pH9．8的NH3－NH4Cl缓冲溶液中,苯酚与4-氨基安替比林和铁氰化钾反应生成红色的显色产物,该显色产物用Water Sep Park－C18固相萃取小柱萃取富集,乙醇洗脱后用分光光度测定。方法的测定范围为0．05－1．2mg／L．方法用于水中痕量苯酚的测定．结果满意。     

利用二次回归正交旋转组合设计优化鸡蛋壳膜唾液酸提取工艺

为研究水解鸡蛋壳膜制备唾液酸的工艺,在单因素试验的基础上,采用二次回归正交旋转组合设计,以水解温度、水解时间、pH值、料液比为考察因素,优选了水解鸡蛋壳膜制备唾液酸的最佳工艺。结果表明:各因素对提取率的影响由大到小依次为:水解温度、水解时间、pH值、料液比。最佳工艺条件为:水解温度为83℃,水解时间为2.1h,pH值为1.4,料液比为101mL/g。在该工艺条件下,唾液酸的得率为85%,工艺稳定,提取率较高,实验验证结果与模型预测值相符合。