GB599214A - Process for separating liquid hydrocarbons from waxes - Google Patents

Abstract

In the separation of liquid hydrocarbons from waxes a sufficient quantity of an organo-silicon compound is added to the mixture to cause the wax dissolved in the oil to crystallise out on cooling so that the wax may be separated by filtration &c. The oil may then be freed from the organo-silicon compound by distillation. When the mixture of oil and wax is so rich in the latter that the mixture is solid at ordinary temperatures, it is melted before adding the organo-silicon compound. The organo-silicon compounds used are selected from the class of organic silicanes and their hydrolysis products and polymers. They have the formula Ry Si Xz in which R is a saturated or unsaturated hydrocarbon radical, X is a halogen, another p hydrocarbon radical or an -OR group, Y has a value 1, 2 or 3 and Z has a value of 1, 2 or 3; when Y + Z is less than 4, the remaining silicon valencies may be occupied by hydrogen. The hydrolysis products and polymers of these silicanes may also be used and are preferred. In an example a wax distillate from petroleum is cooled to freeze out the major portion of the wax, the oil drained off, 15 per cent. by weight of monoamyldiethoxy-silicane added, the mixture cooled further to freeze out the remaining wax, and the mixture filtered. In a second example, 25 per cent. by weight of a monomethyl diethoxysilicane is added to the molten wax obtained from the above filtration and the solution cooled, causing the wax to crystallize out, leaving a small quantity of oil (containing silicane) as an upper layer which may be removed by decantation &c. In the dewaxing of lubricating oils the silicane may be allowed to remain in the oil, the pour point and viscosity index of the latter being thereby improved. The process is applicable to animal and vegetable waxes as well as to hydrocarbon waxes.