ESTIMATION OF SOLUBILITY OF MODEL FREE-RADICAL FRAGMENTS OF PETROLEUM RESINS

The objects of the study are oil resins from various fields: Maly Balyk, Ombinskoye and Danilovskoye (western Siberia) and Kiengop (Udmurtia). The molecular and electronic structures of oil resins have been studied. The experimental part includes separation of resins by eluent method and registration of electronic and IR spectra. The electronic absorption spectra of oil tar solutions from these fields were obtained. Effective ionisation and electron affinity potentials were determined by the method of electronic phenomenological spectroscopy. Experimental values of effective ionisation potentials are in the range from 6,49 to 6,64 eV, electron affinity - from 1.20 to 1,30 eV, values of forbidden zone width from 5,19 to 5,44 eV. The structural parameters were calculated by DFT/B3LYP molecular mechanics methods with the basis set 6-31G* using the GAUSSIAN software package. The obtained calculated data are in good agreement with the experiment. The results show that the molecular fragments of oil resins have PI values ranging from 7,60 to 8,15 eV (free-radicals - from 5,83 to 6,22 eV), the SE values of molecular fragments - from 0,21 to 0,89 eV (free-radicals - from 2,30 to 2,65 eV). The solubility of oil resins in various solvents has been evaluated. The studies have shown that the maximum solubility is possessed by free-radical fragments of oil resins with high effective electron affinity. Insignificant change of electron affinity for free-radical fragments by 0,29 eV causes a significant increase of solubility in toluene: by 9,82 %.