摘要:

The effects on the Kovats and McReynolds indices for a modified set of Rohrschneider solutes have been examined using two different batches of a commercial polysiloxane stationary phase, Dow-Corning DC-710, and five pure oligomers isolated from the mixture. The significant differences that were found between batches appear to be due primarily to changes in the percentage of one oligomer, the cyclic pentamer. This finding emphasizes the desirability of using a pure stationary phase as well as carefully specifying the column temperature in order to improve intra and interlaboratory comparisons of retention indices.

ISSN:0037-2366    

DOI:10.1080/00372367708058062

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The theory of temperature programming has been reexamined. It is shown that a linear program leads to an explicit relation for the retention temperature in terms of the inverse exponential integral. Numerical examples are solved using a straight line plot of the exponential integral together with a plot based on the equivalent temperature concept. A simple explicit expression in terms of common functions for the retention temperature during linear temperature programming was deduced. This was made possible using the inverse log nonlinear program which can be made to approximate quite closely a linear program. This expression was used to explain the constancy of intervals and other phenomena encountered during the linear temperature programming of homologous series.

ISSN:0037-2366    

DOI:10.1080/00372367708058063

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A new and general method of inducing a precipitation from homogeneous solution has been applied to the separation of barium and strontium. The precipitation of barium bromate, a water-soluble compound, is brought about by a gradual change in the composition of the solvent media. An organic compound, such as methanol or tetrahydrofuran, is allowed to diffuse into the original water solution, thus slowly converting the solution into a water-organic mixture. Strontium bromate is about 40 times more soluble in water than barium bromate. The increased solubility plus the greater stability of the strontium MEDTA chelate tend to hold the strontium in solution. The chief advantage of this method over the precipitation of barium chromate is in the preparation of barium compounds. Usually barium must be separated from the chromate before proceeding. However, barium bromate can be easily converted to the oxide, eliminating this separation step.

ISSN:0037-2366    

DOI:10.1080/00372367708058064

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A single-stage flotation process was developed in whichcoalwas floated out and pyrite was depressed. Up to 90% of the pyritic sulfur content of bituminous coal could be removed at 75% coal recovery. The process was applied to three Canadian and two United States coals. Higher coal recoveries were obtained for low sulfur coals; up to 94.4% coal recovery was possible with 18.2% pyritic sulfur removal. Sulfate sulfur, trace elements, and ash were also removed.

ISSN:0037-2366    

DOI:10.1080/00372367708058065

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

When solutions of cupric perchlorate (10−6to 10−2M) are mixed with solutions containing nonequivalent quantities (concentrations) of xanthate (O-alkyl-dithiocarbonate) ions, clear solutions containing soluble nonionic and ionic complexes are obtained, despite the fact that the solubility product for a given metal xanthate salt may be exceeded by several orders of magnitude. Ultraviolet and visible (UV and VIS) spectroscopy, and dc and ac differential polarography have been employed to study these complex species.

ISSN:0037-2366    

DOI:10.1080/00372367708058066

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0037-2366    

DOI:10.1080/00372367708058061

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor