Full Text for July 2011, Volume 55, Number 3

 

Articles in This Issue:

Palladium/Carbon Nanotube Catalysts for Hydrogenation Reactions
Rachel Oosthuizen and Vincent Nyamori of the University of KwaZulu-Natal, Durban, South Africa, review the benefits of using carbon nanotubes (CNTs) as a support for palladium catalysts. In the past, various carbon supports for platinum group metal (pgm) catalysts have been tried and tested. The remarkable properties of CNTs, such as being relatively light in weight and strong in nature, make them worthwhile to investigate as supports for palladium metal catalysts. Research into carbonaceous supports such as CNTs, carbon allotropes and shaped carbon nanomaterials (SCNMs) for the pgm catalyst for hydrogenation reactions is reviewed. The recovery and recycling of precious metals and the use of modified CNTs as supports is also explained.

 

Investigating the Rhenium-Rhodium System for Metallic Phase Behaviour
Rhenium-rhodium solid solutions are used in high-temperature thermocouples, as coatings with high thermal, mechanical and chemical stability and in applications where high hardness is required. An accurate equilibrium phase diagram would lay the foundation for further research into their chemical, physical and material properties and this may allow for further applications of the rhenium-rhodium system. Kirill Yusenko of solid-chem GmbH, Germany, reviews the research conducted in this system and proposes a phase diagram for the rhenium-rhodium system which can serve as a reliable model for representing the experimental data which are available to date.

 

Smithson Tennant; Discoverer of Iridium and Osmium
David Lewis of Groundwork North Yorkshire, UK, investigates the early life of Smithson Tennant, who discovered both iridium and osmium in 1804. This article summarises Tennant’s family roots, education, academic successes and the journey that led to his discoveries. Smithson Tennant was born in Selby, North Yorkshire and had researched the nature of diamond and carbon dioxide and also qualified as a medical doctor prior to the isolation of the two pgms. The 250th anniversary of Tennant's birth falls on 30th November 2011.

 

Can Gold Substitute for Palladium in Cross-Coupling Reactions?
In this issue's Final Analysis, Antonio Echavarren with researchers from the Institute of Chemical Research of Catalonia and Universidad de Valladolid, Spain, reviews and debates the role of gold in cross-coupling reactions. Traditionally, palladium complexes are used to catalyse cross-coupling reactions such as the Sonogashira coupling reaction. The main argument for the use of gold catalysts was that both Au(I) and Pd(0) have identical d¹⁰ configuration. Echavarren and his team discusses the catalytic cycle and behaviour of gold and palladium and also look at homogenous and heterogeneous catalysis. They conclude that, while gold nanoparticles may play a role, homogenous gold(I) catalysts are unlikely to be active when palladium is not present.

Conference Reviews:
The 6th International Conference on Environmental Catalysis was held in Beijing, China, in September 2010. Although this conference covered areas such as clean air and water; clean energy, reducing greenhouse gases, and green chemistry, this review focuses mainly on automotive exhaust catalysis: particulate matter control, three-way catalysts, ammonia-selective catalytic reduction and lean NOx traps.

 

The 9th International Frumkin Symposium was held in Moscow, Russia, in October 2010. The pgms are used extensively as electrode materials for studies of adsorption, nucleation, electrodeposition, electrocatalytic reactions and many other electrochemical processes used in applications such as fuel cells. This review by Alexey Danilov of the A. N. Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences highlights a selection of the work presented, such as the electrochemistry of pgm single crystals and pgm electrocatalysts.

 

Book Reviews:
The current state of the art on the 'heterogenisation' of homogeneous catalysts for fine chemicals production, low to medium volume high-value products, is discussed in "Heterogenized Homogeneous Catalysts for Fine Chemicals Production: Materials and Processes", edited by Pierluigi Barbaro and Francesca Liguori (Istituto di Chimica dei Composti Organo Metallici, Firenze, Italy) and reviewed by Raghunath Chaudhari of the University of Kansas, Lawerence, USA. The pgms catalysts play a huge role in wide ranging applications in fine chemicals and emerging technologies.

 

Professor Peter Maitlis of the University of Sheffield, UK, reviews Professor Bill Griffith's book "Ruthenium Oxidation Complexes: Their Uses as Homogenous Organic Catalysts". A brief history of the discovery and development of ruthenium chemistry is described at the beginning of the book. The main emphasis of the book is on the many different oxidations of organic compounds that are catalysed, mostly by higher oxidation state ruthenium compounds, in solution. The uses and properties of these compounds are also explained.

 

Also included in this issue is a summary of Johnson Matthey's latest market survey of the pgms, "Platinum 2011", which was released on 16th May 2011. In addition to its coverage of supply and demand, it includes special features on fuel cells and the use of pgms in glass manufacturing.

 

Contact
The Editor, Platinum Metals Review, Johnson Matthey Plc, Orchard Road, Royston, Hertfordshire SG8 5HE, United Kingdom; Fax +44 (0) 1763 256359; Email jmpmr@matthey.com

Please click below for PDF file of: