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Chemical engineering is an engineering branch that deals with the chemical production and manufacture of products that undergo chemical processes. This includes equipment design, creating systems and processes to refine raw material, as well as mixing, compounding, and processing chemicals to create products.

Chemistry and Chemical Engineering

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Homologous series of higher fatty acids, higher alcohols, and methyl esters of higher fatty acids have been separated by RPTLC. The values of R M and of the log P Rek partition coefficient from Rekker for the compounds of the homologous series could be correlated with numerical values of topological indexes based on the adjacency matrix (M, °χ, 1χ, °χν, 1χν ), and on the distance matrix (W, A, °B,1B). The most accurate prediction of the R M and log P Rek values of the compounds investigated was achieved by use of monoparametric equations containing one topological index based on the adjacency matrix.

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Two-dimensional thin layer chromatography of twelve flavonoids and three phenolic acids from Betula sp. leaves has been performed in normal-phase systems. Plots showing the dependence of RM on modifier concentration in some non-aqueous systems were used to optimize the chromatographic separation. RM values were correlated for all the chromatographic systems investigated and optimum pairs of systems were then selected for use in two-dimensional TLC separations. Complete separation of the compounds investigated was achieved by use of two optimum non-aqueous mobile phases on silica plates.

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The normal-phase (NP) and reversed-phase (RP) thin-layer chromatographic separations of aminoglycosides (streptomycin, kanamycin, gentamycin, and tobramycin) have been investigated on silica gel and C18 plates, respectively. The mobile phase acetone–2% sodium acetate–acetic acid–butanol, 7 + 6 + 4 + 1 (v/v) was successful for NPTLC and acetonitrile–5 mM sodium acetate buffer (pH 4.6) 4 + 18 (v/v) for RPTLC. The spots were located by use of iodine vapor. The minimum detection limits were in the range 0.4–0.6 μg. The method is a simple and direct approach for detection which does not require pre- or post-chromatographic derivatization.

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Complexes of hydroxy- and alkyloxytetraphenylporphyrins with Cu (II), Zn (II), and Ni (II) have been prepared and their chromatographic behavior in adsorption and partition thin-layer chromatography has been investigated. Gutman topological indexes, Mν, and the screening effect, SE, of the hydrocarbon chains on the electron pairs of the oxygen atoms of –OR groups have been calculated for the metalloporphyrin derivatives studied. The correlation between these and chromatographic retention, expressed as RM values, has been studied.

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Planar electrochromatography (PEC) is a mode of planar chromatography in which the mobile phase is driven by electroosmotic flow. The variables that affect the performance of PEC with an aqueous mobile phase on a bonded octadecylsilyl layer are discussed. These include the magnitude of the applied electric field, the concentration of the buffer salt, the pH of the mobile phase, and the concentration of acetonitrile used as the organic modifier. The effect of changing each of these variables is illustrated by model separations of a mixture of four compounds of diverse structure.

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Planar chromatographic methods thin-layer chromatography (TLC) and over-pressure thin-layer chromatography (OPLC) have been developed for the determination of pigments in plant leaves. Plants with variegated leaves, which sometimes contain both anthocyanins and chlorophyll, are a reasonable material for investigation. Multicolored Coleus, Prunus cerasifera, and Rhus hirta leaves were taken for quantitative determination of anthocyanins and chlorophyll. The separation of pigments from plant leaves, which depends on compound polarity was optimized by appropriate selection of mobile and stationary phases and chromatographic conditions.

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