Abstract The effect of ozonation and dewaxing of Mongolian high-wax oils on the hydrocarbon type composition of petroleum fractions has been studied. The evolution of composition and properties of straight-run petroleum fractions (IBP 180 o C) during reforming on a zeolite catalyst has been examined. It has been demonstrated that after ozonation followed by oil thermolysis the petroleum fractions are enriched with aromatic hydrocarbons while the content of naphthenic ones diminishes. Dewaxing of high-wax oil with liquefied gas has been shown to remove predominantly normal alkanes from petroleum fractions. It has been demonstrated that on catalytic thermal refining of straight-run petroleum fractions the products obtained are depleted of normal paraffin and naphthenic hydrocarbons by 2-5 times, enriched with aromatics by 2-4 times, octane rating of gasoline is enhanced by 18-40 points
