The Preparation of Organo Colloidal Precious Metal Particles

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.

A method for the synthesis of spherical copper nanoparticles in the organic phase

“…The method of solvent-extraction reduction has been proposed for the preparation of the metal nanoparticles [17,18]. Many metal salts are soluble in water and they can be easily transferred into organic solvents with extractants by means of solvent extraction.…”

Morphological evolution of noble metal nanoparticles in chloroform: mechanism of switching on/off by protic species

“…All chloroformic solutions obtained from extraction processes, hereafter are referred to as “liquors”, were characterized by UV-Visible, IR, and Raman spectroscopy. With a procedure similar to those reported elsewhere 8,16 , 50 mL of chloroformic solution containing 1 mM of the extraction agent (CTAB or CTAN) was mixed with 50 mL of an aqueous solution containing the anionic complex (AuBr 4 − or Ag(SCN) 2 − ) in a concentration of 2 mM. The resulting aqueous/chloroformic emulsion was shaken during 15 minutes and both phases were separated after being at rest for one hour in a separating funnel.…”

Ligand-stabilized metal nanoparticles in organic solvent

“…Self-assembly of these nanoparticles by different techniques, either from the bottom-up techniques (assembling particles synthesized in solution) or from the top-down techniques (different lithographic methods), is being pursued. Methods such as solvent extraction/ reduction technique [122,123], gas evaporation technique [124], inorganic particle preparation in methanol or ethanol with the presence of polymeric stabilizer [125,126], reduction of an organometallic precursor dissolved in ethylene glycol [127], and phasetransfer methods [6,128] have been used by several groups in the past. Besides these, synthesis of metal organosol from direct reduction of metal salts containing long-chain amine [129], vapor deposition in methylacrylate [130], and reduction of covalent metal salts in long-chain amine or thiol environment have also been well established.…”