Chemical Composition of Phenolic Fraction of Wood Ablative Pyrolysis Resin

Abstract

The results of chemical analysis of resin phenolic fraction of ablative pyrolysis birch wood are presented. The phenolic fraction was isolated by extraction with 10 % aqueous sodium hydroxide solution. The total yield of the phenolic fraction of ablative pyrolysis resin was 5.3 % per total condensate. The isolated alkaline extract was studied by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS). The data of ¹H NMR spectroscopy were used for quantitative analysis of inputs of definite groups of protons to the total spectrum. Therefore, ¹Н NMR spectrum was divided into seven regions, which corresponds to the following types of protons: aromatic (δ = 6.5–9.0); phenolic OH (δ = 5.0–6.5); Ar–CH₂–Ar (δ = 3.3–4.5); α-CH₃, СН₂, and СН (δ = 2.0–3.3); β-СН₂ and СН (δ = 1.6–2.0); β-CH₃, СН₂, and γ-СН (δ = 1.0–1.6); γ-CH₃ (δ = 0.5–1.0). Proton integral intensity was determined and its input on a proton intensities sum of all distinguished regions of ¹H NMR-spectra were calculated for each region. It has been found that phenolic fraction of ablation pyrolysis resin contains more aliphatic groups in comparison with phenolic fraction of conventional pyrolysis resin, while resin extract contains more aromatic groups. The GC–MS data had shown that the following phenols make the greatest contribution to the formation of ablation pyrolysis resin: 1,2-dihydroxybenzene, 4-methyl-2,6-dimethoxyphenol and 2,6-dimethoxyphenol. Insignificant formation of guaiacol is explained by deciduous wood taken for pyrolysis. IR spectroscopy had shown that pyrolysis resins contain phenolic, alcohol, and carbonyl functional groups and aromatic compounds. The fraction isolated by alkaline extraction contains a significant amount of phenols, which allows its modification for the purposes of obtaining marketable products.

For citation: Mikulintseva M.Yu., Ponomarev D.A., Grachev A.N., Pokryshkin S.A., Kosyakov D.S. Chemical Composition of Phenolic Fraction of Wood Ablative Pyrolysis Resin. Lesnoy Zhurnal [Forestry Journal], 2019, no. 3, pp. 132–142. DOI: 10.17238/issn0536-1036.2019.3.132

The research was carried out using the equipment of the Shared Use Equipment Center “Arktika” of the Northern (Arctic) Federal University named after M.V. Lomonosov.