The content of extractive substances in the products of destruction of bark-woods wastes generated during long-term storage, taking into account the vertical gradient
K.G. Ufimtsev, I.V. Beshley, T.I. Shirshova
Section: Ecologization of industry
The content of extractive substances in the products of the destruction of bark-wood waste (BWW) from the bark dump of JSC Syktyvkar LDK, located in the microdistrict Lesozavod of the Syktyvkar was determined. The chemical composition of the phenolic complex isolated from ethyl acetate extract after removal of resinous substances when infused with hexane was studied. Using the methods of thin-layer and reverse-phase high-performance liquid chromatography, the change in the content and component composition of phenolic compounds depending on the depth of occurrence was traced.
Samples were taken from different depths of the BWW dumps, the thickness of which is 20 m (borehole 1) and 27 m (borehole 2). Extractive substances were extracted from crushed samples by extraction with ethyl acetate at the boiling point of the solvent for four hours. Resinous substances were isolated from the dry residue obtained after distillation of ethyl acetate by infusion with hexane for three days. Quantitative indicators of the content of extractive substances extracted by ethyl acetate from BWW, depending on the depth of occurrence, lie mainly in the range of 1.8–2.9% of dry matter (borehole 1) and 1.4–4.4% (borehole 2). The content of phenolic compounds in ethyl acetate extract after removal of resinous substances mainly lies in the range of 49–64 (borehole 1) and 45–57% (borehole 2).
The phenolic fraction (6–7 m, dump 2) containing the maximum amount of the substance was separated on a column with silica gel using a mixture of chloroform-acetone as an eluent with an increase in the proportion of the latter (from 0 to 100%).
Based on the data of thin-layer and high-performance liquid chromatography, it was found that the composition of the phenolic fraction includes 4 to 8 compounds, one of which is identified by chromatographic and spectral characteristics as dihydroquercetin, considered as a reference antioxidant, and four compounds are classified as hydroxycinnamic and phenolic acids.