Platinum Metals Review - Volume 43, Issue 4, 1999

The Heck reaction for the construction of carbon-carbon bonds, using palladium catalysts, is one of the most valuable strategies in organic chemistry and appears frequently in the literature, usually as homogeneous catalysis. In this review the progress made to date with this reaction is examined, together with the most discussed aspects of the Heck reaction, including a description of its mechanism and the conditions required for success. Some limitations to the homogeneous reaction are mentioned with reasons for proceeding with heterogeneous catalysts, in particular with palladium/carbon. Examples of various heterogeneous Heck reactions are presented and work that we are undertaking to develop methods for the production of cinnamic acids, useful as substrates for the synthesis of “unnatural” amino acids, is discussed. Finally, we present some results from our work using palladium/carbon catalysts for heterogeneous Heck reactions.

The Merensky Reef is a thin layer of igneous rock in the Bushveld Complex in South Africa, which, with an underlying layer, the Upper Group 2 chromitite, contains 75 per cent of the world’s known platinum resources. It was discovered in September 1924 by Hans Merensky, and by early 1926 had been traced for about 150 km. However, large-scale mining of the reef did not develop until a proliferation of uses for the platinum group metals in the 1950s increased demand and price. Successful extraction of metal from the Upper Group 2 chromitite had to wait until the 1970s for metallurgical developments.

The latest in this well-established series of conferences on the chemistry of the platinum group metals, organised by the Dalton Division of the Royal Society of Chemistry, was held at the University of Nottingham, U.K., from 25th to 30th July, 1999. Approximately 250 delegates from around the world heard 46 plenary and invited lectures and viewed 120 posters illustrating a few of the many topics being researched in the platinum metals.

A quarter of a century ago the first autocatalysts were manufactured on a commercial scale by Johnson Matthey at Royston, near Cambridge, in England. This article looks at the background to this major contribution towards cleaning urban air and briefly traces the progress of car catalyst technology since the work of the early autocatalyst pioneers.