Study of potassium O,O'-Dibutyldithiophosphate combining DFT, 31P CP/MAS NMR and infrared spectroscopy.

Dithiophosphates are used in many different industrial applications. To explain their functions and properties in these applications, a fundamental understanding on a molecular level is needed. Potassium O, O'-Dibutyldithiophosphate and its anion have been investigated by means of a combination of DFT and (31)P CP/MAS NMR and infrared spectroscopy. Several low-energy conformations were studied by DFT. Three different conformations with significantly different torsion angles of the O-C bond relative to the O-P-O plane were selected for further studies of infrared frequencies and (31)P NMR chemical-shift tensors. A good agreement between theoretical and experimental results was obtained, especially when the IR spectra or (31)P chemical shift tensor parameters of all three conformations were added, indicating that, because of the low energy difference between the conformations, the molecules are rapidly fluctuating between them.

A theoretical and experimental study of vibrational properties of alkyl xanthates.

Geometrical structure and vibrational modes of potassium and sodium ethyl/heptyl xanthates were studied, using both theoretical and experimental methods. Both Hartree-Fock and density functional theory were used. The experimental method used was infrared absorption spectroscopy (FTIR). Our work showed that vibrational frequencies calculated with density functional theory, using the local density approximation, are in very good agreement with experiments. The results were not improved by using the more sophisticated and computationally demanding B3LYP functional.

n-Heptyl xanthate adsorption on a ZnS layer synthesized on germanium: an in situ attenuated total reflection IR study.

Adsorption of n-heptyl xanthate on synthesized zinc sulfide was followed in situ by monitoring the methylene absorption band at 2925 cm(-1). The zinc sulfide surface used in the adsorption experiments was synthesized on a germanium internal reflection element using the chemical bath deposition method. Characterization of the adsorbent surface was performed by X-ray photoelectron spectroscopy. The time needed to reach adsorption equilibrium varied with the initial concentration of the aqueous potassium heptyl xanthate solution. The amount of adsorbed xanthate ions increased with the concentration of the solution within the range studied (10 microM-50 mM). The experimental data are reasonably well described by the Langmuir adsorption isotherm. Polarized infrared attenuated total reflection (ATR) was used to determine the average orientation of the heptyl chains by measuring the absorbance of the infrared beam polarized perpendicularly and parallely to the plane of incidence. Measured absorbances were corrected for contribution from heptyl xanthate in bulk solution.