Qualitative analysis of Cu2+, Co2+, and Ni2+ cations using thin-layer chromatography.
The M(DEDTC)2 (M = Cu, Co, or Ni) and M(PyDTC)2 (M = Cu or Co) complexes prepared by reactions of sodium diethyldithiocarbamate and ammonium pyrollidinedithiocarbamate with metal (II) nitrates are examined for qualitative analysis and separation using thin-layer chromatography systems. These complexes and their mixtures are spotted to the activated thin layers of silica gel 60GF254 (Si-60GF254) with a 250-microm thickness. Pure toluene and a toluene-cyclohexane mixture (3:1, v/v) are used as mobile phases for running of the complexes. These chromatographic systems are successfully used for qualitative analysis of corresponding metal cations and separation of components in both M(DEDTC)2 and M(PyDTC)2 complex mixtures.
THIN-LAYER CHROMATOGRAPHY : FOUR SIMPLE ACTIVITIES FOR UNDERGRADUATE STUDENTS
To simplify the conventional thin-layer chromatography, four TLC exercises are described which are easy to perform in a high school or college laboratory. In the first exercise, in place of a conventional TLC plate, an ordinary glass test tube, coated with the adsorbent, was used. In the second, the solvent was fed through a glass capillary, fused in the center of a horizontal TLC plate. Third exercise involved a burette to apply the solvent in the center of a TLC plate. In fourth exercise, which resolved the mixture most rapidly, the TLC plate was rotated with the help of an electric motor and solvent was applied by a burette in the center. In order to compare the results a single set of adsorbent, samples and mobile phase was used throughout the work. The described TLC exercises are generally more simple, inexpensive, faster and reproducible than conventional ascending TLC. The purpose of this work was to simplify conventional TLC exercises so that this important analytical technique could be introduced...
Effect of spray nozzle design on liquid-solid contact in fluidized beds
Abstract In industrial fluid cokers the feedstock, consisting of heavy bituminous hydrocarbons, is atomized with steam and injected into a hot fluidized bed of coke. Good and uniform contact of the liquid droplets with the solid particles is required to provide heat for the cracking reactions while minimizing mass transfer effects. Experiments in a pilot plant coker have suggested that the initial particle/liquid mixing, in the spray jet, is rather poor. Experiments in a X-ray scanner showed that liquid droplets and entrained particles accumulate just below the tip of the jet plume to form agglomerates. An experimental technique was used to quantitatively determine the quality of mixing with a variety of nozzle configurations including several novel designs. By improving spray stability, redistributing liquid droplets to the solids-rich region of the jet and increasing the surface area of the gas–liquid jet-fluidized bed interface, liquid/solid contact is improved.