Platinum Metals Review - Volume 51, Issue 4, 2007

Part I of this article (1), which appeared in the July 2007 issue of Platinum Metals Review, described the substantial cost and technical benefits brought to the hydroformylation of propylene with carbon monoxide and hydrogen (an ‘oxo’reaction) by replacing the previous high-pressure cobalt-catalysed technology with a low-pressure rhodium-based catalyst system (the LP Oxo^SMProcess). The background to the rhodium process and its development to the point of first commercialisation were reviewed. This article (Part II) covers some of the improvements made to the LP Oxo^SMProcess after the early plants started operation, and its uses in non-propylene applications.

In industrial applications, platinum is often used in the form of the nominally pure metal, since impurities and alloying elements may adversely affect both its working characteristics and its stability against corrosion, at both ambient and high temperatures. Low strength, typical of a metal of this purity, is accepted in industrial products despite being a significant disadvantage. To optimise the technical parameters for the thermal and mechanical processing of platinum, knowledge is required of its rheological characteristics, including deformation resistance.

Work is being done at Mintek, the University of Leeds and the University of Bayreuth to build up a platinum-aluminium-chromium-ruthenium (Pt-Al-Cr-Ru) database for the prediction of phase diagrams for further alloy development by obtaining good thermodynamic descriptions of all of the possible phases in the system. Binary descriptions were combined, allowing extrapolation into the ternary systems, and experimental phase equilibrium data were compared with calculated results. Very good agreement was obtained for the Pt-Al-Ru system, as described in Part I of this series of papers (1). This paper (Part II) addresses the Pt-Cr-Ru system, with equally encouraging results. The final paper in the series (Part III, to be published in a future issue of Platinum Metals Review) will deal with work on the platinum-aluminium-chromium-nickel (Pt-Al-Cr-Ni) database at the University of Bayreuth. The Pt-Al-Cr-Ru and Pt-Al-Cr-Ni databases will eventually be merged.