Centre for Sustainable Chemical Technologies

Green Oxidation Catalysts

Wednesday 19 September 2012

Time: 13.00–14.00
Location: University of Bath, Building 1 South, Room 0.01 (maps)

New Fe-TAML complexAbstract: Oxidation chemistry plays a central role in many large industrial processes. In situations where chlorine-based oxidants are used in conjunction with organic compounds the formation of potentially harmful organo-chlorine compounds is often an inevitable side reaction. Inexpensive, alternative oxidants that do not pose this problem include oxygen and hydrogen peroxide, and accordingly these are often referred to as “green oxidants”. However, reactions of these reagents with organic materials are usually very slow. There is therefore an important need to develop suitable catalysts that will improve the efficiency and effectiveness of these green oxidants. Prof. Collins and his group at Carnegie Mellon University, USA, have developed a class of iron complexes known as TAMLs® that catalyse oxidations with hydrogen peroxide [1]. These catalysts are water soluble and are highly effective at very low concentrations. In a collaborative research programme we have studied the possibility of using the TAML®/hydrogen peroxide oxidation system to replace the use of chlorine-based bleaches in the pulp and paper industry and also as a remediation treatment for waste-water streams [2]. An important aspect of the tetra-amido macrocyclic ligands that are at the heart of the TAML® catalysts is that they are amenable to chemical modification. We have explored a number of these modifications and have recently developed a new type of TAML® complex (see Figure) that has quite different but complimentary properties to the original class of TAMLs®. In this lecture the use of TAML®/hydrogen peroxide as a green oxidation system will be discussed and our new developments in the synthesis and study of modified TAMLs® will be presented.

[1] T. J. Collins, Acc. Chem. Res. 2002, 35, 782-790

[2] C. P. Horwitz, T. J. Collins, J. Spatz, H. J. Smith, L. J. Wright, T. R. Stuthridge, K. G. Wingate, K. McGrouther. “Iron-TAML Catalysts in the pulp and paper industry.” ACS Symposium Series, (2006) 921 (Feedstocks for the Future) Renewables for the Production of Chemicals and Materials, Edited by Joseph J. Bozell and Martin K. Patel 0841239347, hardback (400 pages), pp156-169.

Brief Biography: L. James Wright completed his PhD degree at the University of Auckland in 1980 under the supervision of Professor W. R. Roper (FRS). After working at the New Zealand Government Research Laboratory (DSIR) for two years, he joined the research group of Professor J. P. Collman at Stanford University as a post-doctoral research fellow. In 1984 he took up a lectureship at the University of Auckland where he is currently an Associate Professor in Chemistry. His current research interests include Green Chemistry applications of metal catalysed oxidation chemistry, new ligand design for homogeneous catalysts, catalytic asymmetric synthesis, organometallic chemistry, and compounds with bonds between transition metals and silicon, germanium, tin or boron.