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The chemical modification of tar with formaldehyde as 37% aqueous solutionhas been studied in the presence of the catalysts. Hydrochloric acid, sulfuric acid, sodium hydroxide and acid tar were used as the catalysts. The effect of the catalyst nature and amount, as well as temperature, process time and initial components ratio on the softening point, penetration, brittle point and adhesion to crushed stone has been determined. The structure of the modified tars was confirmed by IR spectroscopy. The structural-group composition was determined. Arene-formaldehyde resins have been synthesized on the basis of toluene and modified tars using hydrochloric acid as a catalyst. The synthesized resins were characterized using IR spectroscopy. The chemistry of the tar modification with formaldehyde has been proposed.

The possibility of petroleum residues (tar and oxidized bitumen) modification with formaldehyde (37 % aqueous solution) has been studied at the temperature of 393±3 K for 3 h in the presence of organic solvent and using hydrochloric acid as a catalyst. Toluene, p-xylene, naphta solvent and n-octane were used as the solvents in the amount of 0–40 wt % relative to the initial material. By means of IR spectroscopy the resin-like compounds affecting the operational properties of petroleum residues have been detected. These compounds are formed as a result of formaldehyde reaction with residue components and solvent molecules.

The possibility of modification of BND 60/90 bitumen produced at JSC Ukrtatnafta (Kremenchuk, Ukraine) with maleic anhydride has been considered. The effect of maleic anhydride amount, process time and temperature on the operating characteristics of modified bitumen has been studied.

Abstract. 1 The effect of oxidant relative flow rate on the sulfur removal degree and conversion level of coal organic matter has been determined. Sulfur content, as well as ash content and volatiles yield depend on the mentioned values. The optimal oxidant relative flow rate to realize the oxidative desulfurization process has been found with the aim of obtaining raw material for pulverized coal production.