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Pure Appl. Chem., 2001, Vol. 73, No. 7, pp. 1087-1101

http://dx.doi.org/10.1351/pac200173071087

Benign by design. New catalysts for an environmentally conscious age

John Meurig Thomas1,2*, Robert Raja1,3, Gopinathan Sankar1, Robert G. Bell1 and Dewi W. Lewis4

1 Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS, UK
2 Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB2 3QZ, UK
3 Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
4 Department of Chemistry, University College London, 20 Gordon Street, London WC1 0AJ, UK

Abstract: There is a pressing need for: (i) cleaner fuels (free of aromatics and of minimal sulfur content) or ones that convert chemical energy directly to electricity, silently and without production of noxious oxides and particulates; (ii) chemical, petrochemical, and pharmaceutical processes that may be conducted in a one-step, solvent-free manner, and that use air as the preferred oxidant; and (iii) industrial processes that minimize consumption of energy, production of waste or the use of corrosive, explosive, volatile and nonbiodegradable materials. All these needs and other desiderata, such as the in situ production and containment of aggressive and hazardous reagents, and the avoidance of use of ecologically harmful elements, may be achieved by designing the appropriate heterogeneous inorganic catalyst, which, ideally should be cheap, readily preparable, and fully characterizable, preferably under in situ reaction conditions. A range of nanoporous and nanoparticle catalysts, designed, synthesized, characterized, and tested by the authors and their colleagues, that meet most of the stringent demands of sustainable development and responsible (clean) technology is described. Specific examples that are highlighted include: (a) the production of adipic acid (precursor of polyamides and urethanes) without the use of concentrated nitric acid or the production of greenhouse gases such as nitrous oxide; (b) the production of caprolactam (precursor of nylon) without the use of oleum and hydroxylamine sulfate; and (c) the terminal oxyfunctionalization of linear alkanes in air. The topic of biocatalysis and sustainable development is also briefly discussed, and a cautionary note is sounded concerning fast screening methods for the discovery of new inorganic catalysts.