The Preparation of Organo Colloidal Precious Metal Particles

Abstract

Abstract Platinum particles were prepared by reducing the hydrogen hexachloroplatinate extracted in organic solvents from an aqueous solution by these extractants:dioctadecyldimethylammonium chloride(DDAC), trioctylmethylammonium chloride(TMAC), and trioctylphosphine oxide(TOPO). The extraction ratio of platinum(IV) increased in chloroform, isobutyl methyl ketone, and cyclohexane with an increase in the concentrations of the extractants, and then approached a constant state. The extracts were reduced by formaldehyde or benzaldehyde in the presence of water and a base (sodium hydroxide or triethylamine) for several hours at 65 °C. The platinum particles obtained in chloroform and isobutyl methyl ketone were very stable; their diameters were 15–25 Å.