摘要:

The surface areas of a series of pretreated silica gels were measured by a frontal-analysis chromatographic technique using benzene for which the cross-sectional area had been obtained by adsorption measurements on a sample of Sterling MT carbon black as a standard. Much smaller surface areas were found than when nitrogen was used. The chromatographic equilibrium constants for aromatic adsorbates, calculated using the surface areas measured with benzene, point to a change in the adsorption mechanism which was not apparent when nitrogen surface areas were used.

ISSN:0037-2366    

DOI:10.1080/01496396808053463

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Water adducts of 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, tris(4,7-diphenyl-1,10-phenanthroline) Fe(II) perchlorate, tris(4,7-diphenyl-1,10-phenanthroline) Ru(II) chloride, tris(1,10-phenanthroline) Fe(II) perchlorate, and bis(2,9-dimethyl-1,10-phenanthroline) Cu(I) perchlorate had 5.1 ± 0.9, 0 ± 1.3, 6.8 ± 0.6, 5.6 ± 1.5, 4.8 ± 0.7, 6.3 ± 0.6, and 6.5 ± 1.0 molecules of H2O, respectively, associated with them when they were extracted into nitromethane. All deviations are at the 95% C.I.

ISSN:0037-2366    

DOI:10.1080/01496396808053464

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 tris(1, 10-phenanthroline) iron(II) perchlorate ion association chelate was found to be 14 ± 4 when this chelate was extracted into nitrobenzene.

ISSN:0037-2366    

DOI:10.1080/01496396808053465

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Parallelism ofRMvs. composition and logCsvs. composition relationships has been found (Cs=solubility, moles per liter), in spite of the strong molecular interactions involved, for three alkaloids chromatographed in solvent systems of the type (m-xylene +n-pentanol)/buffer solution and (tetralin + cyclohexanone)/buffer solution. Some correlation has also been found between the solubility of two naphthols in nonpolar and weakly polar solvents (hydrocarbons, chlorinated hydrocarbons) and theRMvalues in the corresponding solvent systems of the type organic solvent-formamide. The differences ofRMcoefficients and logCsvalues were found to be individual for a given solute and solvent system, even for closely related solutes (e.g., 1-naphthol and 2-naphthol) for which the ΔRMvalues and Δ logCsvalues tend to be constant for various systems (in other words, ΔRM≠ Δ logCs).

ISSN:0037-2366    

DOI:10.1080/01496396808053466

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Microcrystalline cellulose as an adsorbent in inorganic thin-layer chromatography has been successfully applied to the separation of several cobalt complexes in a variety of solvent systems. The analogy between paper, ion-exchange, and silica-gel chromatographic separations is discussed.

ISSN:0037-2366    

DOI:10.1080/01496396808053467

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The gas-liquid chromatographic behavior of a group of zearalenones has been investigated through the use of both selective and nonselective stationary phases. Separation of these compounds can be effected using conditions similar to those employed for steroid work, differentiation being accomplished on the basis of molecular weight, unsaturation, functional groups, and stereochemistry. Functional group alteration has been employed to improve separations and the quantitative aspects of analysis. Separation of a pair of epimeric alcohols proved to be especially difficult, requiring the use of several approaches. The contribution of the phenolic group at the 2 position to retention behavior is considerably smaller than that of the 4-phenol, a difference ascribed to the ability of the former to intramolecularly hydrogen bond to the carbonyl group of the lactone. These methods have been employed to identify the major urinary metabolite of one of the compounds of this series in the sheep.

ISSN:0037-2366    

DOI:10.1080/01496396808053468

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

In this paper gas-chromatographic techniques are described for the determination of silicon in nickel, copper, and aluminum alloys. The methods are similar to that developed earlier for silicon analysis in iron and steel, comprising essentially a conversion of the alloy with gaseous chlorine followed by gas-chromatographic analysis of the volatile chlorides formed.

ISSN:0037-2366    

DOI:10.1080/01496396808053469

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

An experimental investigation is presented of the foam separation of cyanide, complexed with ferrous iron, using a cationic surfactant, ethylhexa-decyldimethylammonium bromide (EHDA-Br). The effects of pH over the range 5.8–11.4, of iron concentration, and of surfactant and cyanide concentrations on the separation of noncomplexed and complexed cyanide are established. Prior to surfactant addition and foaming, variation of the iron-to-cyanide ratio in the initial solutions produced different species of complexed cyanide, ranging from [Fe(CN)6]4-to polynucleated [FeFe(CN)6]2-, which, in turn, brought about markedly different solution characteristics. Initial solutions containing 0.206 and 0.351 moles of iron per mole of cyanide exhibited contrasting foam separation behavior, at pH 7 and below, but not at pH 8 and above.

ISSN:0037-2366    

DOI:10.1080/01496396808053470

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

A Monte Carlo method is used to study diffusion through packed beds. It is found that the distribution remains approximately Gaussian and can be well represented by a multiplicative factor γ on the free-space diffusion coefficient. For cubically packed beds, γ is given to good approximation by the Giddings theory.

ISSN:0037-2366    

DOI:10.1080/01496396808053471

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The possibility of adapting the well-known mixing device shown in Fig. 1 for production of density gradients with retained hydrostatic equilibrium is investigated. It is shown that a specific form of the unstirred container can be found that gives a strictly linear density course. Instead of specifically shaped containers, specific plungers can be used in cylindrical containers. All pertinent equations arc given. The modified arrangement is useful for falling as well as for rising densities by use of exchangeable plungers.

ISSN:0037-2366    

DOI:10.1080/01496396808053472

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor