Catalytic methods of synthesis of thiophenes from hydrocarbons and hydrogen sulfide

The synthesis of thiophene and alkylthiophenes by the reaction of acetylene, C₄ -C₈ alkanes, and C₄ -C₆ alkenes and alkadienes with hydrogen sulfide in the presence of metal oxides and sulfides as well as their mixtures is examined. The conditions for the testing of catalysts in flow type apparatus in stationary and fluidised catalyst beds are presented. The calculated equilibrium yields of thiophenes from C₄ -C₆ hydrocarbons and hydrogen sulfide are compared with experimental data. Together with the heterocyclisation reaction, the interaction of C₆ -C₈ hydrocarbons with hydrogen sulfide involves dehydrocyclisation with formation of aromatic hydrocarbons. The mechanism of the interaction of C₄ -C₅ hydrocarbons with hydrogen sulfide, investigated by the isotope-kinetic method, is discussed. Certain physicochemical properties of active chromium-containing oxide heterocyclisation catalysts and industrial methods of synthesis of thiophene are described. The bibliography includes 63 references.