Abstract: An antioxidant composition suitable for ester fluid lubricants is the reaction product of diphenylamine and N-aryl naphthylamine in the presence of an organic peroxide. The mole ratio of diphenylamine:N-aryl naphthylamine is about 1:1 to about 10:1. This results in more oligomeric reaction products and significantly less unreacted monomeric residual reactants. The resultant product composition comprises DPA homo-oligomers and DPA-NPA cross oligomers. The diphenylamine and N-aryl naphthylamine are desirably substituted with alkyl groups having from 1 to 20 carbon atoms or styryl groups. The reaction temperature is preferably about 130° to about 150° C. Controlled reaction conditions allow the use of solvents with extractable hydrogen atoms without producing significant amounts of dehydrocondensation between the solvent and the diamines.

Abstract: Apparatus including an elongate pipe (1) for use in the transfer of fluids susceptible to form deposits on cooling such as wax deposits in oil, and a container (12) having a reusable heat source including a supercooled solution, e.g., of aqueous sodium acetate. The container (12) is in heat conducting contact with a surface of the pipe (1), preferably on at least one surface of the container. The deposit may be removed from inside the pipe (1) by locating in heat conducting relation to the pipe a reusable heat source including a supercooled solution, and activating crystallization in the solution liberating heat which causes at least some of the deposit to melt and/or dissolve.

Abstract: An environmentally acceptable, thermally insulating annular fluid comprised of a liquid which is non-aqueous, non-corrosive, and thermally insulating, a clay gellant, and a clay dispersant. A preferred packer fluid includes an ester originated from a vegetable or animal oil as at least a major portion of the liquid phase.