GB491962A - Improvements relating to the treatment of mineral oils - Google Patents

Abstract

Hydrocarbon oils are refined, to produce stable lubricating or medicinal oils, by subjecting the oil for 2 1/2 to 4 hours to the action of air, or a gaseous mixture of free oxygen with inert gases containing approximately 21 per cent of oxygen, at a temperature between 400 and 500 DEG F., in an amount equivalent to 5 to 7 cubic feet of air per hour for every 300 grams of the oil, treating the resulting oxidized oil with sulphuric acid, and separating the resulting acid sludge. The oxidation may be carried out in the presence of copper naphthenate, manganese stearate or other heavy metal soap catalyst, and the oxidized oil may be clay filtered after the treatment with sulphuric acid, either before or after the separation of the acid sludge. Prior to oxidation, the oil may be treated with propane to remove asphaltic constituents, and with acid or selective solvents to remove aromatic and unsaturated compounds. The oxidized oil may be treated with selective solvents to extract undesirable constituents formed during the oxidation process. In examples, lubricating oil distillates are treated with 5 to 7 cubic feet of air per hour per 300 grams of oil (1) for 3 to 4 hours at a temperature of 450 DEG F. in the presence or absence of a small quantity of copper naphthenate, the product being treated with concentrated sulphuric acid, separated from the sludge, and filtered through clay, (2) for 2 1/2 to 4 hours at a temperature of 400 to 450 DEG F., the product being treated with fuming sulphuric acid, separated from the sludge, neutralized, washed with alcohol and filtered through clay, and (3) for 4 hours at a temperature of 450 DEG F., the product being treated with fuming sulphuric acid, neutralized, washed with alcohol and filtered through clay.