A process for the preparation of a colloidal carbon and optionally a colloidal metal oxide organosol so containing

摘要

The invention comprises organosols containing colloidal carbon and optionally a colloidal metal oxide, the colloidal particles having a surface coating of an organic carboxylic acid containing at least 5 carbon atoms. The sol may be prepared by preparing a dispersion in a mixture of an organic liquid and water of colloidal carbon or of colloidal carbon and a colloidal metal oxide in which the colloidal particles are coated with the organic carboxylic acid in an amount of from 2.5/R to 5.6/R moles per mole of colloidal material, where R is the average radius of the colloidal particles in millimicrons; and removing water from the dispersion. The dispersion can be prepared by mixing an organic liquid with a mixture prepared by mixing the organic carboxylic acid with an aqueous dispersion of colloidal carbon or of colloidal carbon and a colloidal metal oxide, or alternatively a carbon organosol prepared by the above method may be mixed with a mixture prepared by mixing an aquasol of a colloidal metal oxide with the organic carboxylic acid. The dispersion may contain colloidal particles of actinide metal oxides e.g. urania and thoria or zirconia, alumina or rare earth metal oxides. If the metal oxide is an antinide metal oxide the colloidal particles may be of a size from 20-50 millimicrons and the amount of acid may be from 0.12-0.28 moles/mole of colloidal material present. The carboxylic acid is preferably benzoic acid but may also be straight chain fatty acids such as caproic, heptanoic, caprylic or decanoic acid, branched chain fatty acids such as isovaleric or isocaproic acid or phenyl derivatives of fatty acids such as a phenyl propionic acid. The organic liquid may be benzyl alcohol, carbon tetrachloride, furfural, tetrachloroethane, primary or secondary monohydric alcohols containing at least four carbon atoms, for example n-butanol, n-amylalcohol, n-hexanol, n-heptanol or n-octanol, branched chain alcohols such as 2-butanol, 2-pentanol or 2-octanol, benzene, ethers such as isopropyl ether and esters such as ethyl acetate.