III International Conference

PP-II-115THE MECHANISM OF PHENOL OXIDATION BY OXYGEN AT THE PRESENCEOF NITROGEN OXIDES AND COBALT COMPLEXES FIXED ON HUMIC ACIDShakieva T.V., Elubaj M.A.Scientific research institute of New chemical technologies and materials of Kazakh NationalUniversity, Almaty, KazakhstanE-mail: rinctm@kazsu.kzThe results of research of kinetic of phenol oxidation by oxygen at 333К in the presenceof nitrogen oxides and complexes of cobalt fixed on humic acid are submitted in article. It isestablished, that in the presence of complexes of cobalt fixed on humic acid and nitrogenoxides it is possible to carry out oxidation of phenol in soft conditions. Fixing of mononuclearcomplexes on humic acid promotes destruction of an aromatic ring, reception of aliphaticaldehydes and cetones while process of oxidation at the presence of binuclear complexes ofcobalt fixed on humic acid runs in formation of benzoquinone. The given system worksstably. Results of this work was obtained in the frames of project NATO SfP 981438"Phenols of industrial wastewaters:detection, conversion, degradation".Phenolic compounds take the third place after heavy metals and mineral oil on occurrencein biosphere and ecological danger and are the basic toxic component of sewage of somemanufactures.It is found by us, that phenol in a water solution is stably oxidized in soft conditions inthe presence of cobalt complexes fixed on humic acid and nitrogen oxides. Conditions atwhich nitrogen oxides are not come out from catalytic cycle are optimized.Injection of sodium nitrite in a solution Co(NО 3 ) 2 – HA – HСlO 4 – С 6 Н 5 ОН – Н 2 О leadsto increasing of redox-potential up to 100-150 mV, increasing of the rate of oxidation ofphenol. The increasing of intensity of bands in IR-spectra, characteristic for NO 2 anddecreasing of intensity of bands NO corresponds to increasing of the rate of absorption ofoxygen and increasing of redox-potential in a solution. The given fact also confirms theassumption that autocatalytic character of oxidation is caused by generation of NO 2 as a resultof reaction (1).2HNO2 + O2→ 2NO2+ H2O(1)The basic part of process occurs at constant containing of NO 2 in a gas and liquid phasethat allows to assume that catalysis of phenol oxidation is concerned with this compound.In whole researched intervals of С Со(NO 3 ) 2 the quantity of the absorbed oxygen does notchange, the degree of transformation of phenol changes within the interval from 99,0 up to87,0 %. The maximal degree of transformation of С 6 Н 5 ОН is observed at the minimal375