Dmitry Kultin

Surface state of sacrificial copper electrode by electropolishing in hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

Anodic dissolution of natural surface-oxidized, air-annealed, cathodically reduced, and cathodically deposited copper in hydrophobic ionic liquid 1-buthyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide under galvanostatic conditions by means of gravimetric measurements was studied. The resulting samples were mirror-like oxide-free copper pattern. The mechanism of the electropolishing of oxidized copper surface was considered. The consequent anodic reactions Cu2O - 1e = Cu(+) + CuO, CuO - 2e = Cu(2+) + O, and Cu - 1e = Cu(+) take place. The electropolishing itself occurs over oxygen-free copper surface due to competitive residual water discharge in the pits and copper dissolution on the roughness.

Ionic liquids based on imidazolium tetrafluoroborate for the removal of aromatic sulfur-containing compounds from hydrocarbon mixtures

Two ionic liquids 1-methyl-3-butylimidazolium (BMImBF4) tetrafluoroborate and 1-methyl-3-octylimidazolium (OMImBF4) tetrafluoroborate were studied from the viewpoint of removing aromatic sulfur-containing compounds from hydrocarbon mixtures using transition metal ions as complexing centers. The values of distribution coefficients (D) indicate that OMImBF4 absorbs benzothiophene (BT) and dibenzothiophene (DBT) better than BMImBF4, which corresponds to the increasing absorption ability of the IL due to the presence of a longer hydrocarbon (octyl) chain in the third position of the imidazolium ring. The influence of additives of various complexes of cobalt(II) on the extraction of BT and DBT was studied in the system OMImBF4–heptane. The planar complex of the Na-salt of 4,5-dicarboxyphthalocyanine of cobalt was found to be the most efficient for the extraction of both substances. The electrochemical approach enables one to purify the IL from BT and DBT by electrochemical oxidation or reduction. This result can be used for searching ways to increase the degree of extraction of BT and DBT in hydrocarbon–IL systems.