Non-aq. metal or cpd. dispersion prodn. - by transfer from aq. dispersion in presence of surfactant and salt, useful for prepg. e.g. magnetic or optical material

摘要

Prodn. of non-aq. dispersions (I) of metal particles (IIA) and/or metal cpd. particles (IIB) involves (a) contacting an aq. (II) dispersion (III) with a water-immiscible, non-aq. liq. (IV) in the presence of a surfactant (V) and opt. water-soluble salt(s) (VI) of inorganic and/or organic acids which have no surface activity; (b) adding (VI) after contact if it is not added in stage (a), so that (II) migrate from the aq. dispersion into (IV), forming a 2-phase mixt. of a non-aq. dispersion phase with dispersed (II) and an aq. phase free from (II); and (c isolating (I) from the 2-phase mixt. The (IV)/(III) vol. ratio is 0.01-50:1, pref. less than 1:1; and the amts. of additives 0.01-5 wt.% (V) and 0.005-30 vol.% (VI) w.r.t. water in (III). (III) may be treated with (pt. of) (V), pref. 0.001-2 wt.% (V), before contact with (IV). (III) contains an organic polymer as protective colloid. (IV) may also contain (II) particles, the particle size of which may be the same as those in (III) or different. Contact involves mixing (III) and (IV) by stirring. USE/ADVANTAGE - The technique is useful e.g. for prepg. dispersions of Au, Ag, Pt, Rh, Pd, Ru, Ir and Os and borides, sulphides and (hydr)oxides of Fe, Ni, Co, Cd, Cu, Ba, Al, In, Sn, Ti, Ta, Si and Zr in CHCl3, cyclohexane, benzene, diethyl ether, MIBK, CCl4, CH2Cl2, ethyl acetate, petroleum ether and silicone oil. (I) are useful in the prodn. of electronic, magnetic, optical, gas-sensor, catalytic and sintered materials, magnetic recording materials etc. The process needs no special equipment, saves energy and provides a simple method of producing large amts. of (I)