(650b) Removal of Alkanethiols from a Hydrocarbon Mixture by Heterogeneous Reaction with Metal Oxides

Thiols can be selectively removed and recovered from a hydrocarbon stream by heterogeneous reaction with oxides and hydroxides of Pb, Hg(II), and Ba. Alkanethiols of lengths n-C6, n-C8, and n-C12 were found to react with powdered metal oxides to form stable thiolates that are solid at room temperature and insoluble in aqueous and organic solvents. The thiolates can be removed from the feed stream by filtration. Once separated, the metal and the original thiols can be recovered by extraction with a dilute acid yielding a metal salt in the aqueous phase and a hydrophobic layer of thiol. The choice of reactive metal oxides may be predicted from simple thermodynamic considerations.