Return to Japanese Patent Table of Contents JP7138579 Abstract The daylight stability, foaming characteristics, colour, engine performance test behaviour, oxygenates content, and thermal stability of wax isomerate oils and/or hydrocarbon synthesis liquid products are improved by a method comprising contacting the aforesaid wax isomerate oil and/or hydrocarbon synthesis liquid products with a silica adsorbent, said silica adsorbent being characterized by possessing a pore size of at least about 100 ANGSTROM (10 nm), preferably at least about 125 ANGSTROM (12.5 nm), most preferably at least about 150 ANGSTROM (15 nm), an alkali/alkaline earth ion concentration, excluding sodium, of greater than about 125 ppm, an iron content of less than about 40 ppm and a zirconium content of less than about 130 ppm. PURPOSE: To improve various characteristics meeting performance guidelines by bringing a wax isomerate oil and/or a hydrocarbon synthesis liquid product, used as a base oil or additive oil of a lubricating oil or special oil, into contact with a specific type of silica absorbent. CONSTITUTION: A hydrocarbon oil selected from a wax isomerate oil, a hydrocarbon synthesis liquid product and a mixture thereof is contacted, in a batchwise manner or continuously, with a silica adsorbent under conditions of a silica loading of about 1 ml/g, a temperature of about 20 to 100°C, a pressure of an atmospheric pressure to about 30 atm., and a time of about 2 to 2 hours. The silica adsorbent has a pore size of at least 100 Å, an alkali/alkaline ion concentration, excluding sodium, of less than about 125 ppm, an iron content of less than about 40 ppm, and a zirconium content of less than about 130 ppm. The hydrocarbon oil collected after the contact with the silica adsorbent is useful as a base oil or additive oil for the preparation of a lubricating oil or special oil as being adapted to a performance guide line with respect to the color, daylight stability, oxygenate content, engine performance test, foaming property, thermal stability and the like. |