Synthesis of sulfides of iron triad elements in n-alkanes

PWIETQ

Abstract

Metal sulfides have a wide range of applications: from refractories and solid lubricants to semiconductors and detectors in radio engineering. The paper presents a critical analysis of methods for producing metal sulfides. Synthesis from simple substances requires significant energy costs for heating mixtures to 1000 °C and long-term homogenization of the product for many hours in an inert gas environment. When conducting out self-propagating high-temperature synthesis (SHS), which has a number of significant advantages, special preparation of the starting materials and repeated grinding of the resulting sinter; the resulting products are in many cases multiphase, the surface of the particles of the metal sulfides formed is covered with a layer of oxysulfides. Synthesis in solution with pumping hydrogen sulfide gas is environmentally unsafe. Among those considered, the synthesis of metal sulfides from non-aqueous solutions was noted. The advantages are shown and its problems are outlined. The conclusions are confirmed by examples of non-aqueous synthesis of sulfides of iron triad elements. Sulfides of iron, cobalt and nickel are synthesized in the medium of liquid saturated hydrocarbons. The method used for producing sulfides is based on combining the process of hydrogen sulfide formation with the main synthesis of sulfides in one reactor. Hydroxides and acetates of the corresponding elements were used as the initial metal-containing compounds. The synthesis was carried out at the boiling point of liquid saturated hydrocarbon (n-undecane, n-dodecane) for eight hours. As a result of the synthesis, crystalline sulfides of iron (II), cobalt (II) and nickel (II) were formed. The method used in the work meets environmental safety requirements (hydrogen sulfide content in the reactor does not exceed 0.8 mg/m³) and is characterized by simple equipment design and low energy consumption. The resulting sulfides were identified methods of X-ray phase and chemical analysis.