Abstract: A method of inhibiting deposit formation in a jet fuel at temperatures above 150° C., whilst not substantially adversely affecting the water separability of the jet fuel. The method includes the step of adding at least one copolymer, terpolymer or polymer of an ester of acrylic acid or methacrylic acid or a derivative thereof to the jet fuel; wherein the copolymer, terpolymer or polymer of an ester of acrylic acid or methacrylic acid or derivative thereof is copolymerized with a nitrogen-containing, amine-containing or amide-containing monomer; or the copolymer, terpolymer or polymer of an ester of acrylic acid or methacrylic acid or derivative thereof includes nitrogen-containing, amine-containing or amide-containing branches.

Abstract: Concentrates for lubricating oil compositions are prepared by blending at elevated temperature: (A) at least one high molecular weight ashless dispersant; and (B) at least one oil-soluble metal detergent; in the presence of (C) at least one metal salt of a dihydrocarbylphosphorodithoic acid wherein the metal of the metal salt is an alkali metal, an alkaline earth metal, or zinc, aluminium, lead, tin, molybdenum, manganese, nickel or copper.