MILESTONES IN CHEMISTRY Oliver Briel The impact of precious metals chemistry in the evolution of modern societies ALREADY PRINTED IN Focus on Milestones in Chemistry OLIVER BRIEL supplement to chimica oggi/Chemistry Today Umicore n. 5 September/October 2011 Member of chimica oggi/Chemistry Today’s Scientific advisory board he “2011: International Year of Chemistry” allows me and polyethylene production involving early transition and my colleagues from the scientific advisory board metals (4), as well as the Monsanto process using a T of Chimica Oggi/Chemistry Today to reflect on the Rhodiumcarbonyl catalyst for Acetic Acid production (5), influence of advances in chemistry research during the or, manufacture of oxo-alcohols by use of Cobalt and past 109 years by looking at who was awarded with the Rhodium complexes as hydroformylation catalysts (6) or Nobel Prize in Chemistry and which socio-economic impact the Wacker Process for the direct oxidation of ethylene did the research contributions of the Laureates have. to name the most significant ones. Far more than 10 Mio As a representative of a precious metals company I will tons of these products are synthesized annually, involving logically take a look at it in the perspective of precious Precious Metals complexes acting as catalysts. metals chemistry. Just recently, in the May issue of 2011 my We should not forget to mention one of the more recent colleague Ian C. Lennon did a formidable job highlighting Laureates, Gerhard Ertl, who was awarded the Nobel the impact of Nobel Prize in Chemistry on fine chemicals (1). Prize in 2007 for “his studies of chemical processes on solid Amongst others he mentioned three recent important Nobel surfaces” (7). Starting already in the 1960s his fundamental Prizes which for sure are still in everybody’s mind: 2010 Nobel work towards understanding thermodynamics and kinetics Prize was jointly awarded to Richard F. Heck, Eichi Negichi on solid surfaces heavily influenced development and 9 and Akira Suzuki for their contributions to developing the design of heterogeneous Platinum Group Metals (PGM) technology of Palladium catalysed coupling reactions. catalysts. Besides synthesis of petrochemicals and fine 2005 prize was awarded to Yves Chauvin, Robert H. Grubbs chemicals making use of catalysts such as Pt/Al2O3 or Pd/C and Richard R. Schrock for their contributions in the field of the most important application involving a heterogeneous olefin metathesis and in 2001 it was awarded to William S. Precious Metals catalyst is certainly emission control for Knowles, Ryoji Noyori and K. Barry Sharpless for their work in combustion engines. Today, almost every vehicle carries a developing methodologies to catalytically and selectively catalytic converter reacting harmful mixtures of off gases build up chiral centres in organic molecules. Note that into nearly clean air. The constant tightening of emission almost all of these methodologies make use of precious regulations requires substantial efforts in the continuous metals underlining their importance in new synthetic improvement of catalyst design. methods for manufacturing fine chemicals. It is also worth Statistics say that there are some 600 Mio motor vehicles mentioning that these recent Laureates were honoured for operating in the world today. Assuming each car is their contributions to modern synthetic methods employing equipped with an exhaust catalyst with an average of 5g homogeneous catalysis. PGM loading, it totals to the astonishing number of 3.000t Some thirty years earlier, in 1973 Ernst Otto Fischer and PGM’s (mainly Platinum, Palladium and Rhodium) that are Sir Geoffrey Wilkinson were awarded the Nobel Prize "for driving around on our earth. Having in mind PGM’s being their pioneering work, performed independently, on the scarce and very costly to extract from ores it is obvious that chemistry of the organometallic, so called sandwich powerful recycling and recovery processes are needed compounds”. Both chemists had significantly contributed when it comes to the end of life of a vehicle. to develop the field of transition metals complex In fact, Precious Metals and their chemistries have an chemistry (2, 3), laying the foundation of a rather outstanding importance towards the development new field in catalysis, homogeneous catalysis. of modern civilizations and a long Soon after their initial discoveries in 1952 history. Starting already during first industrial processes appeared, the antiquity the use of Gold namely the Ziegler-Natta and the and Silver as monetary Philips process for polypropylene metals was dominating MILESTONES IN CHEMISTRY besides jewellery and art. The ever since increasing demand of century, Wilhelm Ostwald was awarded the Nobel Prize of these metals had already made necessary then to develop and Chemistry in 1909 “in recognition of his work on catalysis improve processes for their production and further processing (8). and for his investigations into the fundamental principles Although Platinum was already known from the pre-Columbian governing chemical equilibria and rates of reaction" (9). South American civilisations, the Platinum Group Metals, Wilhelm Ostwald is known for the Ostwald Process which consisting of Platinum, Palladium, Rhodium, Iridium, Ruthenium gave the chemical industry large scale access to nitric acid. and Osmium, have only been discovered and explored much In turn with the development of the Haber-Bosch process in later in Europe, in the 16th century and thereafter. The catalytic 1908 (10) which was giving the industry access to ammonia activity of Platinum was described by J.W. Dobereiner as early as (bound nitrogen), the feedstock for the Ostwald process, the 1823 – which was then regarded more as a lab curiosity. Towards availability of nitrates, indispensable components of synthetic the end of the 19th century main use of Platinum has been in fertilizers, was no longer an issue for the increase of agricultural dental, electric and jewellery applications. From then on the production. To a large extent the industrial implementation picture changed rapidly – meanwhile industrial processes are of these inventions was also driven by the possibility to use producing millions of tons of chemical products making use of the synthetic nitrates and nitric acid for production of explosives outstanding catalytic properties of the Platinum Group Metals. - hence allowing Germany to become independent from With the first Nobel Prize related to precious metals and natural nitrate deposits in Chile that were under British control maybe for one of the most important inventions of the 20th at that time. This example shows us that technology can act both as boon and bane – it depends on us humans to make best use of it. REFERENCES AND NOTES 1. I.Lennon, Chimica Oggi/ Chemistry Today, 29(3), pp. 2-3 (2011). 2. G. Wilkinson, J. Organometal. Chem., 100, p. 273 (1975). 3. E.O. Fischer, W. Pfab, Zeitschrift f. Naturforschung, 7b, pp. 377-379 (1952). 4. K. Ziegler and G.Natta were awarded the Nobel Prize in 1963. 5. R.T. Eby, T.C. Singleton, Appl. Ind. Catal., 1, pp. 275-299 (1983). 6. G. Duembgen, D. Neubauer, Chemie Ingenieur Technik, 41, pp. 974-980 (1969). 7. http://nobelprize.org/ nobel_prizes/chemistry/ laureates/2007/ertl.html# 8. Günter Beck Ed., Edelmetall- Taschenuch, Hüthig GmbH, pp. 1-13 (1995). 9. The Nobel Prize in Chemistry 1909, Nobelprize.org. 24 May 2011. http://nobelprize. org/nobel_prizes/chemistry/ laureates/1909/ 10. Fritz Haber received the Nobel Prize for his work in 1918, see The Nobel Prize in Chemistry 1918, Nobelprize.org. 24 May 2011 http://nobelprize.org/ nobel_prizes/chemistry/ laureates/1918/ 11. Carl Bosch received together with Friedrich Bergius the Nobel Prize for their work on high pressure processes in 1931, see The Nobel Prize in Chemistry 1931, Nobelprize.org. 24 May 2011 http://nobelprize. org/nobel_prizes/chemistry/ laureates/1931/ chimica oggi/Chemistry Today - vol. 29 n. 6 November/December 2011.