PROCESS OF PRODUCTION OF MAGNETIC FLUID ON FLUORIDE-ORGANIC BASE Russian patent published in 1994 - IPC

FIELD: magneto-liquid seals of stirring gears of chemical reactors. SUBSTANCE: for stabilization of dispersions of magnetite produced by coprecipitation of salts of bivalent-trivalent iron with alkali with sizes of particles not less than 10 nm in perfluoridepolyethers method of interphase transfer with the aid of double surface-active agent is used. First surface-active agent (water solved complex BHX-40B) is produced by simple condensation of phenol, diethylamine, fatty acids of fraction C₁₀-C₁₆ and formaldehyde taken in molar proportion 1:2:1:1.5 and is sorbed on particles of aqueous magnetite to make its surface lyophilic. This makes it possible to conduct extraction of their magnetite from aqueous phase to solution of second surface-active agent (amidperfluorideexalkilcarbolic acid) in liquid medium (perfluoride- polyethers). Aqueous solution of first surface-active agent is separated in this case. EFFECT: produced magnetic fluid has magnetization of 15-45 KA/m, is stable in inhomogeneous magnetic fields and is inert to corrosive chemical media.