Platinum Metals Review - Volume 34, Issue 1, 1990

Phase transfer catalysis is an elegant method for ameliorating the reaction conditions of many organic reactions and improving yields and selectivities. A review is presented of the role and scope of the compounds of the platinum group metals as cocatalysts under phase transfer conditions. The most useful improvements have been found in reactions involving the formation of carbon-carbon bonds such as in carbonylations and vinylations, and in reductions with formate.

Stringent standards controlling the emission of exhaust pollutants from gasoline-fuelled spark ignition engines have necessitated studies of many factors that influence the efficiency of the catalysts used for the destruction of carbon monoxide, unburnt hydrocarbons and nitrogen oxides. This review of the literature considers the effects on the catalyst of lead, manganese and phosphorus, which may be present as additives in fuel or lubricating oils. The first two elements can be detrimental to catalytic activity, and also to the environment, so must be minimised. The deactivation caused by phosphorus can be avoided by the use of catalysts designed to be compatable with the specified lubricants. Catalysts containing platinum group metals remain the preferred means of controlling the three designated exhaust gases.

Writing in this Journal over a quarter of a century ago, the late Dr. L. B. Hunt suggested that a number of different types of fuel cell would be required in the future to meet the varied requirements of auxiliary power sources, communications, specialised military applications and vehicular propulsion, and that it would be further into the future before fuel cells would be used as a means of primary power generation. Since that time several papers and conference reports on this application of the platinum metals have been printed here, and a significant number of abstracts of work that has appeared elsewhere, have been published. An increasing awareness of the environmental costs resulting from the use of fossil fuels has reinforced efforts to use such fuels in more effective and less polluting ways. This review summarises the present situation world-wide regarding developments in fuel cell technology, current and proposed applications and commercialisation.