Hydroquinone derivatives are studied as inhibitors of microbiological corrosion and hydrogen absorption by mild steel in water salt media that supports development of sulfate reducing bacteria (SRB). The chosen composition of the media is close to sea water containing biogenic H2S. Н2S content, bacterial titer in corrosive media, its pH, Redox potential Eh, and φ of steel together with the quantity of hydrogen absorbed by surface steel sub-layers, were measured. Protective action against corrosion achieved by the best compounds studied, reached the values of 65…84%, while against hydrogen absorption by steel samples − 60…72%. The presence of the studied derivatives of hydroquinone at concentration C= 5 mMoldm–3 resulted in the decrease of SRB cell count at the rate of 48…84%, the suppression rate being at the values of 29…57%.

The results of study of the derivatives of 1,4-hydroquinone as inhibitors ofmicrobiological corrosion and hydrogen absorption of mild steel in a water-saltmedia supporting the development of sulphate reducing bacteria (SRB) andclose by its composition to the sea water containing biogenic hydrogen sulphide.Content of H2S, bacterial titre in the corrosive meas well as its pH, Eh andpotential of steel '; were determined together with the quantity of hydrogenabsorbed by surface layers of steel. Protective efficiency of the best studiedspecies from corrosion reaches 65...84 %, as for their action against hydrogenabsorption by steel specimen 60...72 %. The decrease of the number of SRBcells due to the action of the derivatives of 1,4-hydroquinone was found to be48...84 %, while the suppression degree 29...57 % (at the concentration of5 mMol/L).Key words:

Analysis of publications is presented on studies of organic steel corrosion inhibitors in environments with hydrogen sulfide with the participation of microorganisms. A relationship is identified between the structure of organic compounds and the composition of their molecules and their efficiency in inhibition of steel corrosion. The effect of organic compounds (phenols, ketones, and quinones) on the metal corrosion process is discussed. A decrease in the rate of cathodic or anodic processes is studied, as dependent on the structure of molecules of organic compounds and pH of the medium. The choice of inhibitors for suppression of corrosion with participation of microorganisms is considered with account for the specificity of their action on a given microorganism and duration of their inhibiting properties: they must not be activated by other substances in the medium, the microorganism must not develop resistance. The mechanism of action of the inhibitor depends on the composition of its molecules, the nature of the corrosive medium and metal. The general stage is the adsorption of its molecules on the metal, depending, in the first instance, on its electronic structure that determines the possibility of chemisorption on the metal surface, as well as on the charge of the metal surface and particles of organic compounds acting as corrosion inhibitors.

The results of quantum chemical computations of isolated molecules(derivatives of 1,4-quinone) performed by using restricted Hartree-Fock (RHF)method with the aid of Gaussian94 software in 3-21G basis set, are reported.Correlation coefficients between quantum chemical characteristics (QCC) of themolecules of inhibitors of corrosion and hydrogen absorption of steel St3 andexperimentally measured efficiencies of such species as the inhibitors in SRBcontaining media, have been calculated.