The separation of glycerides by liquid-liquid column partition chromatography

A liquid-liquid partition chromatography method was developed to separate triglycerides. The solvent was a two phase mixture of acetone, heptane, and water supported on silane treated celite. A study was made of the best means for equilibrating the solvents and support, packing the column, and introducing the sample. The effect of various operating variables such as flow rate, sample size, column length, and solvent compositions was studied using trilaurin and trimyristin as model glycerides. Under the best conditions achieved, it was calculated that glycerides differing by two carbon atoms or one double bond would not separate completely, but glycerides differing by two double bonds or four carbon atoms would be separated. Cocoa butter, a relatively simple triglyceride, was fractionated, and the fatty acid composition of each fraction was determined by gas chromatography. The glyceride composition was calculated and compared with theoretical compositions. The results indicate that useful glyceride separation can be obtained with this system. Probably even more useful separations could be obtained if a more sensitive device were used to detect the triglycerides in the effluent. This would allow the use of solvent compositions which give larger retention volumes and more plate efficiency. Journal Paper No. J-4517 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa, Project No. 1517. Presented at the AOCS meeting in Toronto, Canada, 1962. Based on a thesis presented by B. C. Black in partial fulfillment of the requirements for a master’s degree.     

Extraction of carboxylic acids with neutral extractants

Theoretical Foundations of Chemical Engineering - In the review, the features of the interphase distribution of weak acids (K а < 10–2) in the systems containing neutral...     

液液萃取-毛细管气相色谱法同时测定水中11种氯代苯类化合物

建立了采用液液萃取-毛细管气相色谱法测定水中11种氯代苯类化合物的方法。采用石油醚作为溶剂,萃取水中11种氯代苯类化合物,各类氯代苯类化合物工作曲线回归方程的相关系数均能达到0.995以上;其相对标准偏差均小于5%;其检出限均小于GB 3838—2002和GB5749—2006的限值,能够满足水中氯代苯类化合物检测的需要。     

Application of ion-exclusion chromatography to alkaline pulping liquors; separation of hydroxy carboxylic acids from inorganic solids

Hydroxy carboxylic acids were separated from inorganic solids on a pilot-plant scale by using columns containing a strongly acidic polystyrene cation exchange resin with bed volumes of about 1000 and 200 dm³. The liquor samples were obtained from soda–anthraquinone pulping of pine wood and they were first acidified with sulfuric acid to precipitate most of the lignin and to liberate the hydroxy acids. Under appropriate conditions, using warm water (65°C) as eluent, the liquor sample could be resolved into two distinct fractions consisting mainly of hydroxy acids and sodium sulfate, respectively. This separation method seems promising as a complementary technique in connection with the recovery of aliphatic carboxylic acids from kraft black liquors, although further studies are required to optimize the conditions.     

Preparation of highly purified fatty acids via liquid-liquid partition chromatography

The application of reversed-phase, liquid-liquid partition chromatography to the preparation of highly purified methyl esters of fatty acids is described. The parameters of fractionation of methyl esters by this method are demonstrated with model mixtures of these compounds. Model mixtures are also used to demonstrate the use of adsorption chromatography on columns of silicic acid, impregnated with silver nitrate, in conjunction with liquid-liquid partition chromatography to eliminate fractional distillation in the preparation of polyunsaturated methyl esters. The formation of artefacts of 4, 5 and 6 double bond methyl esters during fractional distillation and their fractionation is described. The use of liquid-liquid partition chromatography for preparative purposes on a large laboratory scale is demonstrated by the preparation of pure methyl linolenate from linseed oil esters. Methyl arachidonate, eicosapentaenoate, docosapentaenoate and docosahexaenoate are also prepared in high purity. Supported in part by the U. S. Public Health Service, NIH grant A-5018, and in part by a contract with the U. S. Dept. of Interior, Fish and Wildlife Service, Bureau of Commercial Fisheries. Presented at the AOCS Meeting in Toronto, Canada, 1962.     

Extraction of copper from aqueous solutions with carboxylic acids

The distribution equilibrium data at 25°C for the extraction of copper from aqueous solutions, containing sodium nitrate or sodium sulphate, by carboxylic acids using toluene, benzene and carbon tetrachloride as diluents have been measured. The carboxylic acids used are n-myristic, n-lauric and n-capric. The results obtained led to the conclusion that the composition of the extracted species corresponds to (CuR₂.HR)₂, being irrespective of both the nature of organic phase and the aqueous phase. The addition of sodium sulphate, instead of sodium nitrate, decreases the extraction efficiency due to the formation a CuSO₄ ion-pair into the aqueous phase. The diluent effect has been related to the activity of the dimerised carboxylic acid in the diluent.     

Efficient separation of phenols from coal tar with aqueous solution of amines by liquid-liquid extraction

In this paper,a method of extracting phenols from coal tar by amines aqueous solution was proposed.The effects of various amines on the extraction properties of phenols in coal tar were researched from the views of molecular structure.The parameters such as molar ratio,concentration,extraction time and temperature for the extraction of coal tar by the monoethanolamine and ethylenediamine aqueous solu-tion were examined.The results show that the organic amine with more amino groups,hydroxyl struc-ture and strong electronegativity exhibited better extraction performance.Under the optimal conditions,the extraction yields of phenols in coal tar by the monoethanolamine or ethylenediamine aqueous solu-tion are above 80％,and the recovery yields of amines reach 99％.Furthermore,the probable geometries of complexes formed by the combination of phenols and organic amines were calculated by density func-tion theory.In addition,several thermodynamic models were evaluated through comparing the relative deviation of simulation results by ASPEN PLUS to the experimental ones,which provide feasibility ther-modynamic models for the simulation of extraction process.The present work affords a mild,efficient and green approach for the extraction of phenols from coal tar by an aqueous solution of amines in indus-try application.     

Solid-liquid separation after liquid-liquid extraction. Spectrophotometric determination of cobalt by extraction of its thioxanthate complex with molten naphthalene

Optimum conditions have been developed for the extraction of cobalt thioxanthate by solid-liquid separation after liquid-liquid extraction.     

溶剂萃取法从RT培司副产废料中提取分离吩嗪

依据吩嗪与RT培司副产废料中其他组分溶解度差异,采用乙醇萃取法,按照废料/乙醇1∶4 g/mL的比例,将废料中易溶部分杂质分离;进一步用乙醇按萃余物/乙醇1∶12 g/mL的比例,将吩嗪、萃余色素加热溶解,同时添加与萃余物质量比为6%的活性炭,在82℃条件下脱色32 min,趁热过滤,除去活性炭及不溶性杂质。产品收率达55%,色泽明亮,纯度达98.5%以上。     

Potential-controlled chromatography for the separation of amino acids and peptides

Potential-controlled chromatography is introduced as a new technique for the separation of amino acids and peptides. The principle of potential-controlled chromatography depends on the use of electrically conductive material as the stationary phase of the chromatographic column. Thus from an electrochemical point of view the packed column can be regarded as a packed-bed electrode. The electrical potential of this stationary phase can be controlled by a potentiostat. The separation of amino acid and peptide molecules during their migration through the column depends on their own electric charge on the one hand and on the electrical potential of the stationary phase on the other. The chromatographic separation of some amino acids could be demonstrated.     

Linoleic acid from safflower oil by liquid-liquid extraction

Summary Tests conducted on a pilot-plant scale have demonstrated that linoleic acid of about 95% purity may be produced from safflower fatty acids containing about 75% linoleic acid, by a liquid-liquid extraction process. Furfural was employed as the selective solvent, hexane as a secondary solvent, and the fractionation was made in a Podbielniak “double-pup” centrifugal extractor. Best results were obtained when the proc This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

液液小体积萃取-气相色谱质谱法测定地表水中2,4-二硝基甲苯和2,4-二硝基氯苯

本文建立了一种液液小体积萃取结合气相色谱质谱法测定地表水中2,4-二硝基甲苯和2,4-二硝基氯苯的方法.实验结果表明,2,4-二硝基甲苯和2,4-二硝基氯苯在10.0～ 160μg·L-1浓度范围内线性关系良好,加标回收均在92.8％～ 103.5％之间,精密度测试结果范围在1.43％～4.05％之间,符合分析测试的要...     

氨基酸分离提纯的研究进展

本文对氨基酸分离提纯常用的沉淀法、离子交换法、萃取法、吸附法等方法的原理及研究进展状况作了较全面的总结。     

液液萃取-液相色谱法测废水中的氯酚

建立液液萃取-液相色谱法测废水中2,4-二氯酚、2,4,6-三氯酚、五氯酚的方法。对废水样品用硫酸酸化至pH值为2³,用二氯甲烷20 mL分2次萃取,合并有机相,再用10 mL浓度为0.5 mol/L K2CO3分2次萃取,定容后,采用可变波长紫外检测器进行定量分析。结果表明,3种氯酚的最低检出质量浓度为2.63,用二氯甲烷20 mL分2次萃取,合并有机相,再用10 mL浓度为0.5 mol/L K2CO3分2次萃取,定容后,采用可变波长紫外检测器进行定量分析。结果表明,3种氯酚的最低检出质量浓度为2.6³.7μg/L,回收率为88.4%3.7μg/L,回收率为88.4%¹06%,测定结果的相对标准偏差为2.67%106%,测定结果的相对标准偏差为2.67%⁴.55%,R2为0.999 74.55%,R2为0.999 7⁰.999 9。该方法所需前处理设备少,操作简单,具有较好的准确度和精密度,适用于废水中2,4-二氯酚、2,4,6-三氯酚、五氯酚的检测。     

乌桕脂脂肪酸提取和分离的研究

由油脂精细化工的理论和实践,提出乌桕脂脂肪酸提取和分离的清洁工艺,并与现有工艺比较,说明该工艺的优越性     

Fractionation of castor oil methyl esters by liquid-liquid extraction

Conclusion The phase equilibrium data are presented for methyl esters-furfural-hexane and methyl esters-nitromethane-hexane at 30°C. The hydroxyl values of ester samples obtained from the furfural and nitromethane phases indicate that furfural and nitromethane can be used as solvents for fractionating hydroxy esters from the mixed esters obtained by the methanolysis of castor oil.     

多级逆流液液萃取法浓缩糠醛的研究

分别选择1,1,1-三氯乙烷和四氯化碳为萃取溶剂,研究液液萃取法浓缩糠醛过程,以UNIQUAC方程为平衡模型,建立逆流模拟计算框图,计算结果表明1,1,1-三氯乙烷和四氯化碳是糠醛浓缩的有效溶剂,在N=4时,分离后糠醛质量分数达99.3%以上,萃余液中糠醛质量分数可降至0.07%以下,以1,1,1-三氯乙烷为萃取剂,分离后糠醛质量分数达99.9%以上,收率达到98.5%以上;在模拟计算的基础上,建立液液萃取装置并进行试验,试验和模拟结果基本一致,研究结果为进一步放大试验研究提供了有效的依据。     

Fractionation of castor oil methyl esters by liquid-liquid extraction

Summary and Conclusions A solubility diagram has been constructed for methanol-castor oil methyl esters-heptane at 8.4°C. and 24°C. A selectivity diagram has been prepared for methanol-castor oil methyl esters-heptane at 8.4°C. and 24°C. Castor oil methyl esters have been fractionated by continuous countercurrent liquid-liquid extraction at 3°C. and at 6°C. with methanol-heptane and heptane-methanol as solvents, using an extraction column containing four equilibrium stages. The methyl ricinoleate fraction produced compared favorably with pure methyl ricinoleate with respect to hydroxyl value and optical activity. It should be noted that there were undoubtedly some mono- and diglycerides in the castor oil methyl esters used in this study. These go along with the methyl ricinoleate and cause discrepancies between hydroxyl value and optical activity (2). The column feeds ranged from 2.9 to 10.3% methyl esters by weight in methanol-heptane. Solvent-feed ratios were from 0.49 to 1.21 lb. per pound. The flow rates were from 706 to 1,020 lb. per hour per square foot of column cross section (based on the cross section of the empty column).     

手性萃取剂与液-液萃取拆分对映体技术研究进展

手性对映体的拆分是当前备受关注的一个研究领域。手性对映体的拆分方法有多种, 手性液-液萃取拆分法是其中有较好发展前景的一种手性对映体拆分技术。本文概述了手性液-液萃取技术的基本原理, 并进一步对酒石酸类手性萃取剂、环糊精类手性萃取剂、冠醚类手性萃取剂、金属络合物类手性萃取剂等不同种类手性萃取剂及其研究进展进行了综述。分析表明, 手性液-液萃取拆分技术对外消旋体特别是药物外消旋体的拆分有较好的效果, 随着对手性萃取剂研究的进一步深入, 手性液-液萃取有望成为一种手性化合物拆分的重要方式。