N-甲酰吗啉作为芳烃萃取剂的萃取原理探究

N-甲酰吗啉作为芳烃的优良萃取剂,在国内已被十几家粗苯加氢企业使用。N-甲酰吗啉对芳烃具有较高的溶解度和选择性,但若控制不当效果仍然不够理想。本文从机理上对N-甲酰吗啉萃取过程给出解释以此来指导实际生产显的尤为重要。     

西藏红景天超临界流体萃取及萃取物的GC-MS分析

探讨了西藏红景天的超临界流体萃取工艺,应用GC-MS方法对萃取物成分进行了分析.结果表明,最佳提取工艺条件为:夹带剂乙醇的体积分数为85%,萃取温度为55℃,萃取压力为30 MPa,萃取时间为2 h.此条件下红景天萃取物得率为5.65%.GC-MS分析鉴定出32种组分,主要为醇类、酯类、烷烃、烯烃等化合物,并应用峰面积归一化法测定了其相对含量.     

Extraction with long-chain amines-VIII Extraction of the chromium-DCTA complex and its colorimetric determination

Chromium(III) is extracted as the DCTA complex by ion-association with trioctylmethylammonium chloride (Aliquat 336-S), into chloroform, and stripped into 1M potassium nitrate for spectrophotometric measurement at 540 nm. Iron(III) copper(II) are removed beforehand by extraction whith phenylacetic acid. High concentrations of nickel or cobalt prevent complete extraction.     

Extraction based on the flow-injection principle : Part I. Description of the Extraction System

An extraction system has been developed, essentially consisting of a pump, a rotary valve and a spectrophotometer. The sample, 12–25 μl, is introduced via the rotary valve into an aqueous stream (flow injection). The aqueous stream, containing the sample plug, is divided into small segments by an organic phase and led into a Teflon coil so that a regular pattern of the two phases is obtained. No air bubbles should be present. Separation of the two phases is achieved in a specially constructed fitting and the absorbance of the organic phase is measured. The construction and performance of the system are illustrated by analysis of caffeine samples. Up to 100 samples/h can be analysed with a relative precision of better than 1%.     

新型的萃取技术——双水相萃取

本文介绍了双水相萃取技术的原理与特点及近年来该技术在生命科学,复杂中药体系的分离以及抗生素药物提取等方面的研究进展。并探讨了其今后的发展趋势。     

Optimization of Soxtec Extraction for the Determination of Polychlorinated Biphenyls (PCBs) in Mussel and Comparison with Soxhlet Extraction,Accelerated Solvent Extraction,and Microwave Assisted Extraction

An on-line Soxtec extraction and cleanup method is optimized for PCBs determination in mussel samples. Soxtec extraction conditions have been optimized using two factorial designs. Optimized extraction parameters were sample weight, anhydrous sodium sulfate weight, solvent volume, alumina weight, and boiling and rinsing times. The results suggest that all PCBs congeners extracted by Soxtec appeared statistically affected by solvent volume. Soxtec quantitative recoveries (8– ?115%) were achieved for all PCBs and method precision (RSD <12%) was satisfactory. The optimized method is compared with three different applied extraction methods, Soxhlet, accelerated solvent extraction, and microwave-assisted extraction. This latter presents the cleanup step on column or assisted by polypropylene membranes. The extraction effectiveness of the four different applied extraction methods for the determination of PCBs in mussel was similar.     

Extraction based on the flow-injection principle: Part 4. Determination of Extraction Constants

A new approach to the determination of extraction constants is described. The aqueous and organic phases, the former containing the counter ion, are pumped continuously as small segments through an extraction coil. The sample ion is introduced into the aqueous phase before it enters the coil, where the ion-pair extraction takes place (during 20 s). After leaving the extraction coil, a certain fraction of the organic phase is pumped through the flow-cell of the spectrophotometer. The extraction constants are calculated by slope analysis from the experimental data (absorbance and counter ion concentration). The constants usually agreed within ±0.1 (log units) with values obtained from batch experiments.     

Effect of Chaotropes on Lipase Back Extraction Recovery in the Process of Reverse Micellar Extraction

Chaotropes could significantly enhance lipase activity recovery in reverse micellar back extraction. However, the mechanism of chaotropes promoting the release of enzyme from reverse micelles was not clear. In this study, chaotropes were added in the process of lipase reverse micellar extraction, and back extraction recovery was improved. In back extraction, at 0.6 M urea in stripping solution, 94.60 % total extraction recovery was obtained. Meanwhile at 0.3 M guanidine hydrochloride, nearly 65 % lipases were released into the stripping solution. DLS and Karl Fischer method results showed that the presence of urea in stripping solution could weaken the electrostatic interaction between lipase and cetyltrimethylammonium bromide molecules, promoting lipase release from reverse micelles, and guanidine hydrochloride could stimulate lipase and free water molecules enwrapped in reverse micelle release into the stripping solution. These experimental results provide a clue for understanding the mechanism of chaotropes influencing on protein recovery in reverse micelle back extraction.     

固相萃取分离铀

铀是重要的核工业原料,也是一种有较强化学和生物毒性的重金属。从各类含铀水体系中分离和回收铀对缓解铀资源短缺,保护人类健康和生态环境安全都具有重要的科学和实际意义。本文简要回顾和评述了近15年来具有代表性的新型固相萃取材料及其在铀分离方面的应用研究,并对相关材料在铀分离领域的应用前景进行了分析和展望。     

研究报告(191~196)基于微波技术的翻白草多糖提取工艺研究

采用醇沉水提工艺,使用微波技术提取翻白草中多糖.先通过单因素分析法对提取工艺进行优选,并选取4个因素进行正交实验.得到翻白草中多糖的最优提取工艺为:先使用料液比为1∶30的乙醇进行醇沉20 min,再以液固比为70∶1的水(p H为7.0)作为提取剂,在60℃下微波提取10 min.在最优提取工艺下对翻白草不同部位(根、茎、叶)的多糖含量进行分析,发现翻白草的茎部多糖的含量最高,其次为根部和叶部.     

Study on the Solvent Extraction with Radio-Tracers. I. Extraction Study on Protactinium-233 with the Noyltrifluoroacetone

Protactinium-233, separated from the irradiated thorium, was used as a tracer for the extraction study with thenoyItrifluoroacetone. From the results obtained by the variation of acidities of HCl with the constant concentration of TTA in benzene, a slope of ?2 was obtained by plotting the distribution coefficients against acidities. With a definite acid concentration of HCl in the aquous solution and by the variation of TTA concentration, a slope of 4 was obtained by plotting the distribution coefficients against the concentration of β-diketone. With these results, species extracted by the organic layer was assumed to be Pa[TTA]₂[HTTA]₂. If the composition of the organic layer was changed by the addition of the following solvents into the TTA in benzene solution, the order of the extraction was found as follows: n-amyl alcohol > cyclohexane > chloroform > n-hexane > carbon tetrachloride > benzene > nitrobenzene > hexone > cyclohexanone > n-butyl alcohol.     

Extraction of novocaine from the aqueous phase

The distribution ratios of novocaine and p-aminobenzoic acid between water and 12 organic solvents were correlated with linear multiparameter equations.     

金属萃取平衡与软-硬酸碱规则

软硬酸碱规则从宏观角度描述化合物的形成及性质,在配合物稳定性的判断方面有广泛应用.前文^[1]报道了萃取速率常数与金属离子的软硬酸碱强度的关系,本文研究了萃取平衡常数与金属离子的软硬酸碱强度的关系.     

胶质液态泡沫的萃取性能

制备了包含萃取剂的胶质液态泡沫（ＣＬＡ）,测定了包含Ｎ１９２３或ＴＢＰ的ＣＬＡ萃取醋酸的性能,以及包含Ｐ５０７的ＣＬＡ萃取稀土离子时稀土在ＣＬＡ水质滑腻壳层中的渗透系数．结果表明将萃取剂包含于ＣＬＡ中,对其粒径、粘度及稳定性等不产生明显影响,但对萃取分配及传质十分有利．     

Microcalorimetric Study of the Oscillating Extraction System

The power–time curves of the oscillating extraction system were determined at different temperatures for the extraction of hydrochloric acid and acetic acid with primary amine N₁₉₂₃ (R–CH(NH₂)–R¹), R, R ¹ represent alkyl of C_9–11 in chloroform using the titration microcalorimetric method. The apparent activation energy was calculated from the induction period (t _in), the first oscillation period (t ^p.1) and the second oscillation period (t _p.2). This revised version was published online in August 2006 with corrections to the Cover Date.     

Extraction chromatography in the TBP-HNO3 system

As an application of a TBP/XAD-4 column for the analytical separation of uranium, neptunium, plutonium and americium, the elution behavior of these elements as a function of their redox reactions has been studied. Subsequently, two effective procedures to carry out a quantitative separation of the actinide elements from each other were established by combining extraction chromatography in the TBP-HNO₃ system and the redox reactions of the actinide elements.     

花生油提取工艺研究

以花生为原料,研究回流法,索式提取法和超声波辅助提取花生粗油脂的工艺条件,结果显示超声波提取在低温短时间内提取率有优势。通过单因素试验和正交试验优化了超声波辅助提取花生粗油脂的工艺条件。结果表明：超声波辅助提取花生粗油脂工艺的最佳条件是：石油醚作为溶剂,料液比1：12（g/mL）,提取温度35℃,提取时间25min,超...