Preparation of Ni—W aromatic hydrocarbon hydrogenation catalysts by breaking reverse emulsions or suspensions of a precursor in hydrocarbon feedstock

Abstract

Reverse emulsions (hydrocarbon feedstock)/(aqueous precursor solution) for synthesizing aromatic hydrocarbon hydrogenation catalysts have been prepared using the water-soluble salts (NH₄)₂WS₄ and Ni(NO₃)₂ · 6 H₂O as precursors. It has been found that the optimum stabilizer for the emulsions is the nonionic surfactant SPAN-80. The resulting emulsions exhibit low catalytic activity in the hydrogenation of aromatic hydrocarbons; it has been shown that the activity of the systems in hydrodearomatization reactions is adversely affected by the presence of water. A procedure for preparing suspensions of solid precursor particles in a hydrocarbon feedstock by the removal of water from the resulting reverse emulsions has been developed. The catalytic activity of the resulting suspensions in the hydrogenation of aromatic hydrocarbons has been studied using naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as examples. It has been shown that the catalytic activity of the suspensions is higher than that of the reverse emulsions of the same composition. It has been found that the feedstock should be subjected to additional sulfurization with elemental sulfur for further sulfiding the surface of the nickel—tungsten catalyst. The W: Ni molar ratio of 1 : 1 has been found to be optimum.