Platinum Metals Rev., 1963, 7, (4), 133
New Homogeneous Catalysts for Hydrogenation
Platinum-Tin Chloride Complexes
None of the noble metal complexes previously found active for homogeneous hydrogenations has efficiently catalysed the hydrogenation of ethylene and acetylene, but it has recently been reported by workers at du Pont in a letter to the American Chemical Society (1) that the complex compound formed by interacting chloroplatinic acid with stannous chloride dihydrate in methanol in the absence of air will catalyse these reactions at room temperature and atmospheric pressure. Acetylene yields a mixture of about 25 per cent ethylene and 75 per cent ethane.
The role of the stannous chloride is to accelerate the rate at which the unsaturated hydrocarbon becomes co-ordinated to the platinum, and also to stabilise the platinum compound against reduction by hydrogen. The mechanism of the catalysis is not discussed, but complex anions derivated from stannous chloride and chloroplatinic acid in which the platinum is in the +2 oxidation state were characterised as their triphenyl-methylphosphonium salts.
In a second communication, from Professor Wilkinson and his co-workers in the Inorganic Chemistry Research Laboratories of Imperial College (2), the preparation of analogous Rh(I), Ru(II) and Ir(II) complex anions having the formulae [RuCl2(SnCl3)2]2− and [IrCl2(SnCl3)2]2− is also described; these were isolated as their tetra-alkylammonium salts.
- 1 R. D. Cramer,, E. L. Jenner,, R. V. Lindsey and V. G. Stolberg, J. Am. Chem. Soc, 1963, 85, ( 11 ), 1691
- 2 A. G. Davies,, G. Wilkinson and J. F. Young, ibid., 1692