PROCEEDINGS

of the Tomsk Polytechnic Institute named after S. M. Kirov,
holder of the Order of the October Revolution and the Order of the Red Banner of Labor

Vol. 257　　　　　　　　　　　　　　　　　　　　　　　　　1973

USE OF CHROMATOGRAPHY AND SPECTROSCOPY TO STUDY PEAT RESINS

G. I. Kravtsova, K. K. Stramkovskaya, S. I. Smolyaninov

(Presented by the scientific-methodological seminar of the organic departments of the Chemical-Technological Faculty, TPI)

Peat resin, unlike resins from the pyrolysis of other solid fuels, has been studied least of all. The available works [1–5] were carried out mainly using chemical methods of analysis and, in some cases, adsorption chromatography.

In the present work, two samples of peat resins were investigated—resin obtained in the pyrolysis of peat-ore materials (experimental resin) and resin from the semicoking of peat—using methods of chromatography, infrared, and ultraviolet spectroscopy.

The resins obtained, the phenols and neutral oils isolated from them, and also fractions of these products were characterized by physicochemical indices and by fractional, group, and elemental compositions. Light fractions of the neutral oils and phenols were studied by gas–liquid chromatography. Neutral oils isolated directly from the resins were studied by methods of adsorption chromatography, infrared, and ultraviolet spectroscopy.

To investigate the individual composition of the neutral oils (distillates up to 135°C, 5-degree fractions), two methods were applied. The first was based on using, as the liquid phase, Apiezon L applied to Inza brick of grade INZ-600 in an amount of 15%. The analysis was carried out on an KhL-4 chromatograph using a packed column 7.2 m/6 mm, at a thermostat temperature of 220°C and a carrier-gas (helium) flow rate of 100 ml/min. According to the second method, vacuum oil VM-4 was used as the liquid phase (15% solution in benzene), preliminarily thermostated at 270°C for a period of

6 hours, and a copper capillary column, 100 m/0.5 mm. The analysis was carried out on a “Khrom-2” chromatograph at a column temperature of \(95^\circ\mathrm{C}\) and a carrier-gas (nitrogen) pressure at the column inlet of \(5.88 \cdot 10^4\ \mathrm{N/m^2}\) \((0.6\ \mathrm{kgf/cm^2})\).

The results of these investigations are given in the summary table, from which it is evident that the fraction of neutral oils with initial b.p. \(135^\circ\mathrm{C}\) has a very complex composition (42 components) and is represented mainly by aromatic compounds of the benzene series.

Table I

Content of individual substances in the neutral
oils of the resins studied, wt. %

Identification and quantitative determination of low-boiling phenols (up to \(230^\circ\mathrm{C}\)) were carried out on a “Khrom-2” chromatograph with a capillary column \(50\ \mathrm{m}/0.5\ \mathrm{mm}\) at a thermostat temperature of \(152^\circ\mathrm{C}\). Tricresyl phosphate (10%) with the addition of phosphoric acid (5%) was used as the phase. The conditions developed provided a fairly clear separation of the components under study; in this fraction, 25 compounds were found.

The isolation of neutral oils and their adsorption separation was carried out according to the following scheme. The adopted method of adsorption separation made it possible to isolate methane–naphthene hydrocarbons, four groups of aromatic compounds, and oxygen-containing compounds; for these, physicochemical characteristics were determined, empirical and homologous formulas were calculated, and, as indicated above, IR and UV spectra were recorded.

The combined use of the above-mentioned analytical methods made it possible to establish that the paraffin–naphthene hydrocarbons are represented by paraffins and olefins of normal structure with a number of carbon atoms from 6 to 26–31. Among the aromatic hydrocarbons, the first group consists of alkylated monocyclic compounds; the second, predominantly of bicyclic compounds; in the subsequent groups, tri- and polycyclic aromatic hydrocarbons predominate. The oxygen-containing compounds are condensed aromatic structures with the presence of carbonyl and hydroxyl groups.

Conclusions

1. A study was carried out on two samples of peat resins using methods of chromatography, infrared spectroscopy, and ultraviolet spectroscopy.

2. By the method of gas–liquid chromatography, the light fractions of neutral oils and phenols were investigated. It was shown that they have a complex composition.

3. By the method of adsorption chromatography in combination with IR and UV spectroscopy, the neutral oils isolated directly from the resins were studied.

4. It was shown that the composition of the neutral oils includes paraffin–naphthene hydrocarbons, aromatic compounds, and oxygen-containing compounds.

Literature

1. V. E. Rakovskii. General Chemical Technology of Peat. Moscow–Leningrad, Gosenergoizdat, 1949.

2. S. V. Kashirina, V. E. Rakovskii. Proceedings of the Academy of Sciences of the BSSR, Series of Chemical Sciences, 3, 1965, 81–85.

3. K. V. Grigor’eva, N. M. Karavaeva. Proceedings of the Academy of Sciences of the USSR. Division of Technical Sciences. Metallurgy and Fuel, 4, 1961, 166–170.

4. L. P. Malashenko, E. A. Papatina, N. D. Edemskaia, M. A. Orlova. In: Energy-Technological Utilization of Fuel. Moscow, Publishing House of the Academy of Sciences of the USSR, issue 4, 1963, 91–98.

5. N. F. Budnik. In: Energy-Technological Utilization of Fuel. Moscow, Publishing House of the Academy of Sciences of the USSR, issue 1, 1960, 139–149.