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
1Davy Faraday Research Laboratory, The Royal Institution
of Great Britain, 21 Albemarle Street, London W1S 4BS, UK; 2Department
of Materials Science & Metallurgy, University of Cambridge, Cambridge
CB2 3QZ, UK; 3Department of Chemistry, University of Cambridge, Lensfield
Road, Cambridge CB2 1EW, UK; 4Department 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.
*Lecture presented at the 38th IUPAC Congress/World
Chemistry Congress 2001, Brisbane, Australia, 1-6 July 2001. Other presentations
are published in this issue, pp.1033-1145.
**Corresponding author.
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