GB437779A - Improvements in or relating to the method of dewaxing a wax-bearing oil, to a lubricating oil of low pour point, and method of preparing same - Google Patents

Abstract

Polymerized cyclic hydrocarbons, for use as dewaxing agents for petroleum oils, are made by heating naphthalene anthracene, fluorene, phenanthrene, benzene or homologues thereof with aluminium chloride or similar Friedel-Crafts reagent preferably p between 90 to 150 DEG C. Naphthalene is dissolved in kerosene and heated above 90 C. for 6 hours with an equal amount of aluminium chloride. The resulting product is distilled under reduced pressure to remove tetra methyl naphthalene, b -b -dinaphthyl and tetramethyl picene (crackene or naphanthracene derivative), leaving a tarry residue which may be dissolved in benzene and petroleum naphtha added to yield a precipitate of tetranaphythyl (C40H26). Aluminium chloride may be replaced by the halides of zinc, antimony, iron, cadmium, boron, manganese, nickel or tin.ALSO:Mineral oils are dewaxed by adding a condensation product of an aromatic hydrocarbon formed by heating with a Friedel-Crafts catalyst, chilling and separating the precipitated wax. Naphthalene, anthracene, fluorene, phenanthrene, benzene or homologues thereof are heated with aluminium chloride at 90--150 DEG C., and the condensed product is distilled to remove the lighter fractions up to 300 DEG C., which consist of tetra-methyl-naphthalene, b -b -di-naphthyl and tetramethyl picene, leaving a tarry residue which is used as the dewaxing agent. This tar may be dissolved in benzene and petroleum ether added, whereupon a precipitate of tetra naphthyl is formed, which after drying may be used as the dewaxing agent. Aluminium chloride may be replaced by the halides of zinc, antimony, iron, cadmium, boron, tin, manganese or nickel. The oil is diluted with solvents such as benzene, acetone, dichlorethylene, naphtha, methyl ethyl ketone, aliphatic alcohols or mixtures thereof, and a small amount of the tarry residue is added. The resulting solution is chilled and the wax separated in a centrifuge or filter. Filter acids as diatomaceous earth may be added before the chilling stage. Condensation products formed at a high temperature are particularly effective for heavy residual oils.