A new process for the preparation of ultrafine polymetallic particles

摘要

The use of an alkali or alkaline earth hydride to reduce a solution of mixed metallic salts in an organic solvent.- DETAILED DESCRIPTION - A process for preparing ultrafine polymetallic particles comprises reduction of an organic solution of metal salts , at least one metal salt having a standard oxidation potential , Eo Mn+/M (25oC.), greater than -1.18V, in the presence of an alkali or alkaline earth metal hydride. The process is operated at a temperature lower then or equal to the solvent reflux temperature.- INDEPENDENT CLAIMS are also included for the nanometric polymetallic particles thus obtained and their use as catalysts in olefin hydrogenation and aromatic coupling reactions.TF - TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred components: The metal salts are alkoxides organic acid salts, preferably acetates or acetylacetonates, or halides. Also present in the reaction mixture is an alkoxide or aminoalcoholate of an alkali(ne earth) or transition metal. At least one salt has an oxidation potential Eo Mn+/M (25oC.) lower than -1.2V and is a salt of V, Zr, Ce, Ti, Hf and Al ; and the salts of oxidation potential greater than -1.18V contain Ni, Co, Fe, Cu, Zn, Cd, Cr, Mn, Pd, Ag, Pt, Au, Bi and/or Sb. The nanometric particles obtained have an average crystallite dimension less than 4 nm and a close association of the metals internally within the grains.- ORGANIC CHEMISTRY - The organic acid salt is the acetate or acetylacetonate. The alkoxide can be formed in situ by action of the hydride on an alcohol preferably tert-butanol, 2-methyl-2-pentanol, phenol, monoethylether diethylene glycol, neopentane, cyclohexanol, ethanol or isopropanol. The reaction mixture may also include a nitro or phospho ligand , chosen from bipyridines and terpyridines or triphenylphosphine, 1,2-bis(diphenylphosphino)ethane, alkylphosphines and arylphosphines