摘要:

A universal separation index, the extent of separation, is proposed and mathematically described. This index is easily calculated, normalized, invariant to a permutation in indices, and conceptually similar to the De Donder extent of reaction. It applies to any type of separation system, any initial or final level of component purity, any concentration profile (if one exists), any initial amount of components, multicomponent systems, and both separation and mixing processes. The index is employed to characterize one of the simplest of all separation systems—the single equilibrium stage.

ISSN:0037-2366    

DOI:10.1080/01496396808052211

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

It is proven that, given a constant flow rate throughout the system, the (2n) possible arrangements (including 180° rotation of any column along the long axis) ofnchromatography columns arranged in tandem yield identical elution curves (and therefore identical values of mean residence time and variance). The columns must be of the same cross-sectional area but each can be of arbitrary length. The proof is independent of the nature of the packing material in each column and holds for any given input distribution in time and/or constitution.

ISSN:0037-2366    

DOI:10.1080/01496396808052212

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

From certain organic solvents containing organic phosphorus compounds such as trioctylphosphine oxide (TOPO), bis(2-ethylhexyl)orthophosphoric acid (HDEHP), or tri-n-butylphosphate (TBP) and hydrochloric acid, scandium is much less retained on the strongly acidic cation-exchange resin Dowex 50 than are all other members of the rare-earth group. Thus on this resin in a medium which is 95% tetrahydrofuran, 5% 6 M hydrochloric acid, and 0.1 M TOPO, the separation factor for scandium-rare earths is greater than 4 × 103(corresponding to distribution coefficients of < 1 for scandium and >4 × 103for all the other rare-earth elements). By the use of this system a complete and highly effective separation of tracer and macro quantities of scandium from the rare earths can be achieved on a column of this exchanger. Among the organic solvents investigated, tetrahydrofuran gives the best results. The effectiveness of the organic extractants increases in the order TBP < HDEHP < TOPO

ISSN:0037-2366    

DOI:10.1080/01496396808052213

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

An instrument is described for the continuous separation of particles by means of electrophoresis. The effect of field strength, electrolyte flow rate, and sample flow rate on migration distance and particle band width were investigated. The interrelationships between the various operational parameters and particle band resolution are discussed.

ISSN:0037-2366    

DOI:10.1080/01496396808052214

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Utilizing the Karl Fischer titration technique for the quantitative determination of water, the number of water molecules associated with a molecule of chelate when extracted from water into chloroform was determined for five chelates in the acetylacetone and dimethylglyoxime types. In this investigation no increase in the number of associated water molecules was observed as the bulkiness of the ligand was increased by the substitution of electron-withdrawing groups for methyl groups on the ligand, nor was any increase noted when the metal ion in the chelate was less sterically hindered to the approach of water molecules than in the phenanthroline chelates. The fact that the chelate contains hydrogen-bonded sites does not appear to affect the number of water molecules associated with the chelates investigated here.

ISSN:0037-2366    

DOI:10.1080/01496396808052215

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

An equation of the formy=ABecxndescribes the effect of associated water on the distribution ratio of this nonaqueous extraction. It was also determined that there are 9.6 ± 1.5 molecules of water associated per molecule of the chelate when extracted from water into nitromethane or 1-decanol.

ISSN:0037-2366    

DOI:10.1080/01496396808052216

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

An experimental technique has been developed to determine the effect of solvent polarity on the removal of associated water molecules from metal chelates during extraction. It was found that tris(4,7-diphenyl-1,10-phenanthroline)iron(II) perchlorate had two spheres of water associated with it—one that could be displaced by organic solvent and one that could not.

ISSN:0037-2366    

DOI:10.1080/01496396808052217

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The number of molecules of water associated with the bis(l,10-phenan-throline)Cu(I) perchlorate extracted into nitrobenzene was found to be 12 ± 3 and for the bis(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)Cu(I) perchlorate in chloroform, 0 ± 3.

ISSN:0037-2366    

DOI:10.1080/01496396808052218

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

A study was undertaken to determine the relative ease of formation and stability of straight-chain primary and secondary alkanols capable of forming urea inclusion compounds. The compounds studied were 1-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-heptanol, 1-octanol, 3-octanol, 4-octanol, 1-nonanol, 4-nonanol, 5-nonanol, 1-decanol, 1-undecanol, and 1-dodecanol. 1-Heptanol was the shortest alcohol that formed an inclusion compound by the procedure employed. The ease of formation of a straight-chain alcohol was proportional to the number of uninterrupted methylene groups (—CH2—) present. The ease of urea inclusion compound formation generally decreases as the functional group approaches the center of the chain. These conclusions were based on X-ray powder diffraction measurements and the weight of recovered products under equilibrium conditions.

ISSN:0037-2366    

DOI:10.1080/01496396808052219

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

A combination of fractional distillation and normal freezing was used to purify 1,3-dimethyl-5-t-butylbenzene. Analysis by gas chromatography indicates that the final product was > 99.999% pure. A number of physical constants are given of the pure material.

ISSN:0037-2366    

DOI:10.1080/01496396808052220

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor