Thermal reactions between alkanes and H2S or thiols at high pressure

► Confined pyrolysis in gold cells of n-octane/H2S mixture is investigated at high pressure. ► The main products are thiophene, alkylthiophenes, octanethiols and alkyl-thiacycloalkanes. ► Reactivity of thiol is also studied at 350°C in pyrolysis of n-octane/thiol mixtures. ► The formation pathways of the main products, which are similar for both reactant mixtures, are proposed. Confined pyrolysis in gold cells of n-octane/H2S mixtures was carried out between 310°C and 350°C under 700bar for durations of 3–13 days. The main products were thiophene, alkylthiophenes, octanethiols and alkyl-thiacycloalkanes and their quantities were measured. Some experiments were also carried out at 350°C on n-octane/thiol mixtures and the results were compared to those obtained with H2S. The formation pathways of the main products, which are similar for both reactant mixtures, are proposed.