GB767587A - Improved process for refining petroleum fractions - Google Patents

Abstract

Petroleum fractions are sweetened by oxidation of mercaptans contained therein by the action of oxygen or a gas containing oxygen in the presence of an iminophenol and a Group VIII metal compound to thereby form in situ in the product a chelate compound of the iminophenol and the metal. Iminophenols referred to are those formed by the reaction of a hydroxy benzaldehyde or hydroxy naphthaldehyde, e.g. ortho-hydroxy benzaldehyde, with an aliphatic, aromatic or hydroaromatic diamine, e.g. ethylene and propylene diamines, diaminodimethylamine and diaminodipropylamine; specific iminophenols mentioned are disalicylal ethylene, disalicylal propylene, disalicylal cyclohexylene, disalicylal napthylene, disalicylal dipropylamino and disalicylal phenylene diimnes. The Group VIII metal compound may be a metal salt, e.g. a fatty acid salt such as cobalt acetate, stearate, oleate and ricinoleate, or may be cobalt naphthenate, alcoholate, enolate, phenolate, alkyl phenolate, amino phenolate, alkylphthalate, or acetyl acetonate. Alternatively, the petroleum fraction and the iminophenol may be circulated through a bed of activated carbon charged with cobalt nitrate. The iminophenol and metal compound may be added to the petroleum fraction as a solution in a solvent. Solvents referred to for the iminophenol are an alcohol, e.g. methanol, and toluene; and for the metal compound, alcohol, methanol, phenol, cresol, an alkyl phenol and kerosene. The sweetening process may be accelerated by adding alkali, such as sodium or potassium hydroxide, e.g. in an aqueous solution of methanol or ethanol. A trace of free sulphur or a labile sulphur compound such as an alkaline sulphide may also be present. The process may be washed with water or dilute alkali or filtered through decolourizing clay. Petroleum fractions specified are natural or cracked fractions such as gasoline, kerosine or white spirits. Specification 701,443 is referred to.