Hydroconversion of Thiophene Derivatives over Dispersed Ni–Mo Sulfide Catalysts

Abstract

The activity of unsupported Ni–Mo sulfide catalysts is studied in the hydroconversion of benzothiophene and dibenzothiophenes in the temperature range of 340–380°С and at an increased H₂ pressure and in the СО/H₂О system. The structure of dispersed catalysts formed by the in situ high-temperature decomposition of oil-soluble precursors (molybdenum hexacarbonyl, nickel naphthenate) is investigated by TEM. Effects of СО/H₂О molar ratio, water mass content in the system, and CO pressure on the activity of the catalysts and yields of the products are explored. It is shown that, in the СО/H₂О system, the highest conversion of benzothiophene and dibenzothiophene is attained at a temperature of 380°С, a СО pressure of 5 MPa, and a СО/H₂О molar ratio of 2. The introduction of alkyl substituents into a dibenzothiophene molecule causes a reduction in the rate of reaction that predominantly occurs via the hydrogenation of aromatic rings. The catalyst activities in hydrogenation under H₂ pressure and in the СО/H₂О system are comparable.