Solubilization of platinum in KOH-B2O3 molten medium

• Water-soluble platinum compounds are synthesized in a molten KOH-B 2 O 3 medium. • The solubilization efficiency is enhanced by controlling heating temperature. • Size and shape of alumina reaction containers also affect the efficiency. • Presence of Al-O-Al linkages in the compounds inhibits the solubilization. • Fluoride addition to the medium reduce the inhibitory effect. Platinum (Pt) was converted into water-soluble compounds in a KOH-B 2 O 3 molten medium. By controlling the heating temperature and shape of the alumina reaction container, the Pt compounds were synthesized efficiently. The reaction with the alumina container generates Al–O–Al linkages in the compound, resulting in the formation of an insoluble Pt compound. Fluoride addition to the medium prevented insolubilization of the compounds.